Pelvic injuries account for 3% of all skeletal fractures.¹ Injury to the sacroiliac (SI) joint is frequently associated with unstable pelvic ring fractures, which are potentially life-threatening injuries. Surgical fixation of these injuries is preferred to nonoperative treatment given the potential for improved reduction and early mobilization and weight-bearing, thereby decreasing perioperative morbidity and improving functional outcome.²

The classic method of surgical fixation of the SI joint consisted of open reduction and internal fixation. This method carried a substantial risk for large dissection, iatrogenic nerve injury, and increased blood loss to the already traumatized patient.³ Percutaneous fixation allows for a shorter operating time, decreased soft-tissue stripping, and decreased blood loss compared with a traditional open procedure.⁴ However, posterior pelvic anatomy is complex and variable, and reports have found screw misplacements as high as 24%⁵ and neurologic complication rates up to 18%.^6-9 

Various imaging modalities, including fluoroscopy,⁵ computed tomography (CT),^6-7 fluoroscopic CT, and computer-assisted techniques^5,9 have been used to achieve proper screw placement. Conventional fluoroscopy is the standard for intraoperative screw placement. However, acceptable reduction of the SI joint and proper implantation of the screws without perforation of the neural foramina is challenging, especially when coupled with difficulties of fluoroscopic imaging and variations in pelvic anatomy. 

Sacral dysplasia has been reported to occur in up to 20% to 40% of the population and has significant implications in patients indicated for iliosacral screw placement.¹⁰ Incorrect placement of iliosacral screws may result in iatrogenic neurovascular complications.^11-13 Malpositioned screws using fluoroscopic guidance have been reported in 2% to 15% of patients with an incidence of neurologic compromise between 0.5% and 7.7%. As little as 4° of misdirection can result in damage to neurovascular structures.¹⁴

At our institution, we routinely obtained postoperative CT to evaluate the placement of SI screws. The objective of this retrospective study is to evaluate the rate of revision surgery of percutaneous SI screw fixation, to determine whether CT is an accurate tool for evaluation of the reduction and the need for revision surgery, and to decide if any violation of the neural foramina is safe.

Materials and Methods

After institutional review board approval, we retrospectively reviewed and evaluated medical records and radiographs of all patients who sustained unstable pelvic ring fractures between July 1, 2005, and June 30, 2010. We identified all patients who were treated with closed reductions and percutaneous iliosacral screw fixation, according to the method described by Routt in 1995.⁴ We excluded all pelvic fractures in patients who underwent open reduction for the posterior injury or did not have percutaneous SI screws placed, those with spinal injury, and those without follow-up. Of the 46 patients who met the inclusion criteria were 26 men and 20 women with a mean age of 42 years (range, 16 to 73 years). Motor vehicle accidents accounted for 13 cases; 19 were crush injuries and 14 were falls from height. Seventeen patients (37%) met the radiographic criteria for sacral dysmorphism. Forty-two of the 46 patients were polytrauma patients with associated musculoskeletal injuries and/or abdominal, chest, or head injuries.

Six patients presented with some neurologic deficit at the time of injury; all fractures were closed. The initial imaging study included plain anteroposterior (AP), inlet, and outlet radiographs of the pelvis and a pelvic CT scan. Using the classification of Young and Burgess,¹⁵ there were 3 vertical shear injuries, 13 lateral compression–type injuries, 17 anterior-posterior–type injuries, 7 sacral fractures, and 6 combination- or unclassifiable-type pelvic injuries. Of the sacral fractures, there were 3 Denis zone 1, 3 Denis zone 2, and 1 Denis zone 3. 

The pelvic CT scan included the entire pelvis from the ilium to the ischial tuberosities. Each scan consisted of either a 5.0-mm or a 2.5-mm sequential axial image. A picture archiving and communication system (PACS) workstation using Centricity version 2.1 (GE Medical Systems, Waukesha, Wisconsin) was used to analyze each scan with a bone algorithm. On PACS, each initial displacement was characterized by the amount of SI joint widening at the level of the S1 and was measured using digital calipers.   

Surgery

Mean time to surgery was 4 days (range, 2 to 15 days) after the injury. A total of 51 SI screws were implanted in 46 patients. We achieved closed reduction of the posterior pelvic ring by various techniques, including compression with percutaneous partially threaded screw fixation. In the cases in which the posterior ring lesion was associated with a pure pubic symphysis disruption, the anterior pelvis was initially reduced and stabilized with small-fragment plate fixation (Synthes, Inc, Paoli, Pennsylvania). The posterior complex was stabilized with 1 screw in 41 patients, 2 cases required a transiliac screw, and 2 screws (S1 and S2) were placed in each of the remaining 3 cases. Definitive stabilization of the posterior pelvis was achieved with percutaneous, partially threaded 7.3- or 7.5-mm–diameter cannulated screws (Synthes, Inc, and Zimmer Inc, Warsaw, Indiana, respectively) in 42 fractures and 6.5-mm screws (Synthes, Inc) in 4 fractures. In 11 cases where the fracture was through the sacrum, fully threaded cannulated screws were used to avoid compression. Screw insertion was performed under fluoroscopic guidance with inlet, outlet, and lateral sacral views. One of 2 fellowship-trained trauma surgeons performed the surgeries. Rehabilitation plans were customized to each patient based on concomitant injuries. 

Postoperative Assessment

AP, lateral sacral, and inlet and outlet postoperative radiographs were taken in all cases within 24 hours after surgery. Pelvic CT was also obtained within 24 hours of surgery to review reduction and screw placement.

Using the measurement tool on the PACS system, we measured the penetration of the screw into the foramen. Screws were graded as intraosseous (completely contained within the sacral bone), skived (less than 2 mm of partial penetration into the S1 foramen), or extruded (the screw not contained by the bone). Screw penetration of the S1 was evaluated on the radiographic images as well as the axial images of the CT scans.

After surgery, the senior orthopedic resident and attending surgeon performed and documented detailed neurologic evaluations. They reviewed the medical record for neurologic deficit following surgical fixation.   

Results

The mean follow-up time was 12 months (range, 8 months to 2 years). Two patients expired secondary to associated injuries. There were no early deaths related to the pelvic surgery. Stable fixation, including bone or ligamentous healing, as well as full weight-bearing status, was noted in every case. No case exhibited loss of reduction or implant failure or infection.

According to Matta’s criteria of anatomic reduction within 1 cm, all patients were found to have satisfactory reductions.⁷ Six of 46 patients had documented preoperative neurologic deficits. After percutaneous screw fixation, 10 of 46 patients had postoperative neurologic deficit, 2 of which were unchanged from preoperative evaluation. Of the 8 patients with new/altered postoperative neurologic deficit, CT showed neural foramen penetration greater than 2.1 mm in only 2 patients. Both patients underwent screw revision, resulting in improved neurologic deficit. The remaining 4 patients did not have foramen penetration and improved their neurologic function over the course of 2 weeks with return to presurgical status by 6 weeks without necessitating screw removal.

Twenty-three of the 51 screws (45%) had some violation of the S1 foramen on the CT. There were 17 patients with dysmorphic sacrums in which 21 S1 screws were placed. Eleven of  21 (52%) screws showed some penetration of the S1 foramen on CT. There were 29 patients with normal sacral morphology in which 30 S1 screws were placed. Twelve of 30 (40%) screws penetrated the S1 foramen. All violations were in the superior one-third position of the foramen. Two of 46 (4%; 1 with dysmorphism, 1 without) had a new neurologic deficit associated with the surgery (Table). CT showed sacral foramen penetration, and both screws were revised with a better neurologic examination.

High-resolution CTs were obtained in 32 patients, while 14 patients underwent the standard 5.0-mm–cut CTs. Of the 32 patients in which a 2.5-mm high-resolution CT was obtained, 20 (62.5%) had evidence of screw penetration (Figures 1, 2). All violations of the S1 neural foramen were in the superior portion of the foramen. 

When compared with patients who had a 5.0-mm CT, the patients who underwent a high-resolution CT were more likely to show neural foramen penetration (P = .3). The average screw penetration into the S1 neural foramen measured 3.3 mm (range, 1.6-5.7 mm) in dysmorphic sacrum and 2.7 mm  (range, 1.4-7 mm) in normal sacrum. However, in our study, any foramen penetration of less than 2.1 mm on CT did not result in neurologic deficit.  

Discussion

Pelvic fractures are fairly common and represent approximately 5% of all trauma admissions and 3% of all skeletal fractures nationwide.¹ The current treatment for SI disruption is either nonoperative or operative. Surgical fixation is technically demanding and surgeons often need a long learning curve to acquire the demanding technique because of the limitations of radiographic visualization of the relevant landmarks.¹⁶

Letournel¹⁷ developed the technique for iliosacral screw fixation for the treatment of posterior pelvic ring injuries, where 1 or 2 large screws (6.5-7.3 mm in diameter) are inserted under fluoroscopic guidance through the ilium, across the SI articulation, and into the superior sacral vertebral bodies using percutaneous techniques. Currently, the standard procedure to accomplish the percutaneous placement of iliosacral screws derives mainly from the technique described by Matta with the C-arm fluoroscopy visualizing the pelvis in 3 views: strict AP, inlet, and outlet views.⁷

Routt and colleagues⁴ recommend a strict lateral view of the sacrum, particularly when crossing the narrow zone of the sacral alar. They reported high union rates and accurate placement of the screws.⁴ There are limitations to the use of biplanar fluoroscopy because the intraoperative images are not orthogonal, with the average arc (67º) between the ideal inlet and outlet. However, because of the variability in sacral anatomy, CT guidance was recommended by others.^2,6,8,18 Operating in a CT suite had other complications. Misinterpretation of CT led to “in-out-in” screws, which resulted in neurapraxia. 

In our study, we used the technique described by Matta and colleagues for placement of the screws and performed a postoperative CT to evaluate screw placement and to assess pelvic reduction.⁷ We had a high penetration rate using CT, which increased with better resolution, even though none of the radiographs showed any obvious evidence of misplacement of the screws. Ebraheim and colleagues⁶ described the relationship of the S1 nerve root in its neural foramen and found it to be approximately 8.7 mm inferior and 7.8 mm medial to the starting point for a pedicle screw. Given these numbers, it is possible that a large amount of skiving can be tolerated contingent on an adequate reduction of the SI joint. 

Because of our high rates of skiving and low rates of neurologic deficit, a new “safe zone” for screw insertion can be expanded to include skiving of the S1 neural foramen up to 3 mm without fear of nerve root injury. However, drilling and screw insertion at higher speeds can also cause neurologic injury secondary to thermal injury or soft tissue being caught up in a rotating drill/screw. 

Evaluation of placement of percutaneous SI screw placement in our study resulted in neural foramen penetration in 43% of SI screws, which is higher than other studies.^14,19,20 Our study showed that screw penetration up to 2 mm does not correlate with neurologic deficit. Iatrogenic neurologic deficit secondary to perforation of the foramina occurred in only 1 patient. Penetration of the foramina in all cases was in the superior portion of the foramen. We propose that there is a safe zone within the S1 neural foramen, and small amounts of penetration in the superior one-third of the foramen on axial CT images do not correlate with neurologic deficit. This potential safe zone is predicated on adequate reduction of the SI joint. 

Neural foramen penetration shown on postoperative CT does not necessarily correlate with neurologic deficit. A postoperative CT is not indicated unless there are findings of a postoperative nerve injury. Our ideal screw placement skives the superior S1 foramen allowing for a larger screw diameter in a safe zone.

CT-guided placement has been proposed; however, concerns about radiation exposure, cost, and feasibility with similar outcomes compared with fluoroscopic-guided screw placement has resulted in its falling out of favor.

Iatrogenic nerve injuries are reported to occur in 0% to 6% of all percutaneous SI screw placement.^14,21 Risk factors for iatrogenic nerve injury while using fluoroscopic guidance include sacral morphologic abnormalities, presence of intestinal gas, or contrast.²² Although these may be minimized with proper use of fluoroscopy, obtaining anatomic reduction as well as a thorough understanding of the pelvic morphology, the surgeon must be prepared to obtain further studies, such as a CT scan, if there is postoperative neurologic deficit.

Based on our findings, we do not routinely obtain a postoperative CT for SI screw placement, unless there is concern for malreduction or there is neurologic deficit. We also believe that up to 2 mm of foramen penetration is safe and does not result in neurologic deficit.

Pelvic injuries account for 3% of all skeletal fractures.¹ Injury to the sacroiliac (SI) joint is frequently associated with unstable pelvic ring fractures, which are potentially life-threatening injuries. Surgical fixation of these injuries is preferred to nonoperative treatment given the potential for improved reduction and early mobilization and weight-bearing, thereby decreasing perioperative morbidity and improving functional outcome.²

The classic method of surgical fixation of the SI joint consisted of open reduction and internal fixation. This method carried a substantial risk for large dissection, iatrogenic nerve injury, and increased blood loss to the already traumatized patient.³ Percutaneous fixation allows for a shorter operating time, decreased soft-tissue stripping, and decreased blood loss compared with a traditional open procedure.⁴ However, posterior pelvic anatomy is complex and variable, and reports have found screw misplacements as high as 24%⁵ and neurologic complication rates up to 18%.^6-9 

Various imaging modalities, including fluoroscopy,⁵ computed tomography (CT),^6-7 fluoroscopic CT, and computer-assisted techniques^5,9 have been used to achieve proper screw placement. Conventional fluoroscopy is the standard for intraoperative screw placement. However, acceptable reduction of the SI joint and proper implantation of the screws without perforation of the neural foramina is challenging, especially when coupled with difficulties of fluoroscopic imaging and variations in pelvic anatomy. 

Sacral dysplasia has been reported to occur in up to 20% to 40% of the population and has significant implications in patients indicated for iliosacral screw placement.¹⁰ Incorrect placement of iliosacral screws may result in iatrogenic neurovascular complications.^11-13 Malpositioned screws using fluoroscopic guidance have been reported in 2% to 15% of patients with an incidence of neurologic compromise between 0.5% and 7.7%. As little as 4° of misdirection can result in damage to neurovascular structures.¹⁴

At our institution, we routinely obtained postoperative CT to evaluate the placement of SI screws. The objective of this retrospective study is to evaluate the rate of revision surgery of percutaneous SI screw fixation, to determine whether CT is an accurate tool for evaluation of the reduction and the need for revision surgery, and to decide if any violation of the neural foramina is safe.

Materials and Methods

After institutional review board approval, we retrospectively reviewed and evaluated medical records and radiographs of all patients who sustained unstable pelvic ring fractures between July 1, 2005, and June 30, 2010. We identified all patients who were treated with closed reductions and percutaneous iliosacral screw fixation, according to the method described by Routt in 1995.⁴ We excluded all pelvic fractures in patients who underwent open reduction for the posterior injury or did not have percutaneous SI screws placed, those with spinal injury, and those without follow-up. Of the 46 patients who met the inclusion criteria were 26 men and 20 women with a mean age of 42 years (range, 16 to 73 years). Motor vehicle accidents accounted for 13 cases; 19 were crush injuries and 14 were falls from height. Seventeen patients (37%) met the radiographic criteria for sacral dysmorphism. Forty-two of the 46 patients were polytrauma patients with associated musculoskeletal injuries and/or abdominal, chest, or head injuries.

Six patients presented with some neurologic deficit at the time of injury; all fractures were closed. The initial imaging study included plain anteroposterior (AP), inlet, and outlet radiographs of the pelvis and a pelvic CT scan. Using the classification of Young and Burgess,¹⁵ there were 3 vertical shear injuries, 13 lateral compression–type injuries, 17 anterior-posterior–type injuries, 7 sacral fractures, and 6 combination- or unclassifiable-type pelvic injuries. Of the sacral fractures, there were 3 Denis zone 1, 3 Denis zone 2, and 1 Denis zone 3. 

The pelvic CT scan included the entire pelvis from the ilium to the ischial tuberosities. Each scan consisted of either a 5.0-mm or a 2.5-mm sequential axial image. A picture archiving and communication system (PACS) workstation using Centricity version 2.1 (GE Medical Systems, Waukesha, Wisconsin) was used to analyze each scan with a bone algorithm. On PACS, each initial displacement was characterized by the amount of SI joint widening at the level of the S1 and was measured using digital calipers.   

Surgery

Mean time to surgery was 4 days (range, 2 to 15 days) after the injury. A total of 51 SI screws were implanted in 46 patients. We achieved closed reduction of the posterior pelvic ring by various techniques, including compression with percutaneous partially threaded screw fixation. In the cases in which the posterior ring lesion was associated with a pure pubic symphysis disruption, the anterior pelvis was initially reduced and stabilized with small-fragment plate fixation (Synthes, Inc, Paoli, Pennsylvania). The posterior complex was stabilized with 1 screw in 41 patients, 2 cases required a transiliac screw, and 2 screws (S1 and S2) were placed in each of the remaining 3 cases. Definitive stabilization of the posterior pelvis was achieved with percutaneous, partially threaded 7.3- or 7.5-mm–diameter cannulated screws (Synthes, Inc, and Zimmer Inc, Warsaw, Indiana, respectively) in 42 fractures and 6.5-mm screws (Synthes, Inc) in 4 fractures. In 11 cases where the fracture was through the sacrum, fully threaded cannulated screws were used to avoid compression. Screw insertion was performed under fluoroscopic guidance with inlet, outlet, and lateral sacral views. One of 2 fellowship-trained trauma surgeons performed the surgeries. Rehabilitation plans were customized to each patient based on concomitant injuries. 

Postoperative Assessment

AP, lateral sacral, and inlet and outlet postoperative radiographs were taken in all cases within 24 hours after surgery. Pelvic CT was also obtained within 24 hours of surgery to review reduction and screw placement.

Using the measurement tool on the PACS system, we measured the penetration of the screw into the foramen. Screws were graded as intraosseous (completely contained within the sacral bone), skived (less than 2 mm of partial penetration into the S1 foramen), or extruded (the screw not contained by the bone). Screw penetration of the S1 was evaluated on the radiographic images as well as the axial images of the CT scans.

After surgery, the senior orthopedic resident and attending surgeon performed and documented detailed neurologic evaluations. They reviewed the medical record for neurologic deficit following surgical fixation.   

Results

The mean follow-up time was 12 months (range, 8 months to 2 years). Two patients expired secondary to associated injuries. There were no early deaths related to the pelvic surgery. Stable fixation, including bone or ligamentous healing, as well as full weight-bearing status, was noted in every case. No case exhibited loss of reduction or implant failure or infection.

According to Matta’s criteria of anatomic reduction within 1 cm, all patients were found to have satisfactory reductions.⁷ Six of 46 patients had documented preoperative neurologic deficits. After percutaneous screw fixation, 10 of 46 patients had postoperative neurologic deficit, 2 of which were unchanged from preoperative evaluation. Of the 8 patients with new/altered postoperative neurologic deficit, CT showed neural foramen penetration greater than 2.1 mm in only 2 patients. Both patients underwent screw revision, resulting in improved neurologic deficit. The remaining 4 patients did not have foramen penetration and improved their neurologic function over the course of 2 weeks with return to presurgical status by 6 weeks without necessitating screw removal.

Twenty-three of the 51 screws (45%) had some violation of the S1 foramen on the CT. There were 17 patients with dysmorphic sacrums in which 21 S1 screws were placed. Eleven of  21 (52%) screws showed some penetration of the S1 foramen on CT. There were 29 patients with normal sacral morphology in which 30 S1 screws were placed. Twelve of 30 (40%) screws penetrated the S1 foramen. All violations were in the superior one-third position of the foramen. Two of 46 (4%; 1 with dysmorphism, 1 without) had a new neurologic deficit associated with the surgery (Table). CT showed sacral foramen penetration, and both screws were revised with a better neurologic examination.

High-resolution CTs were obtained in 32 patients, while 14 patients underwent the standard 5.0-mm–cut CTs. Of the 32 patients in which a 2.5-mm high-resolution CT was obtained, 20 (62.5%) had evidence of screw penetration (Figures 1, 2). All violations of the S1 neural foramen were in the superior portion of the foramen. 

When compared with patients who had a 5.0-mm CT, the patients who underwent a high-resolution CT were more likely to show neural foramen penetration (P = .3). The average screw penetration into the S1 neural foramen measured 3.3 mm (range, 1.6-5.7 mm) in dysmorphic sacrum and 2.7 mm  (range, 1.4-7 mm) in normal sacrum. However, in our study, any foramen penetration of less than 2.1 mm on CT did not result in neurologic deficit.  

Discussion

Pelvic fractures are fairly common and represent approximately 5% of all trauma admissions and 3% of all skeletal fractures nationwide.¹ The current treatment for SI disruption is either nonoperative or operative. Surgical fixation is technically demanding and surgeons often need a long learning curve to acquire the demanding technique because of the limitations of radiographic visualization of the relevant landmarks.¹⁶

Letournel¹⁷ developed the technique for iliosacral screw fixation for the treatment of posterior pelvic ring injuries, where 1 or 2 large screws (6.5-7.3 mm in diameter) are inserted under fluoroscopic guidance through the ilium, across the SI articulation, and into the superior sacral vertebral bodies using percutaneous techniques. Currently, the standard procedure to accomplish the percutaneous placement of iliosacral screws derives mainly from the technique described by Matta with the C-arm fluoroscopy visualizing the pelvis in 3 views: strict AP, inlet, and outlet views.⁷

Routt and colleagues⁴ recommend a strict lateral view of the sacrum, particularly when crossing the narrow zone of the sacral alar. They reported high union rates and accurate placement of the screws.⁴ There are limitations to the use of biplanar fluoroscopy because the intraoperative images are not orthogonal, with the average arc (67º) between the ideal inlet and outlet. However, because of the variability in sacral anatomy, CT guidance was recommended by others.^2,6,8,18 Operating in a CT suite had other complications. Misinterpretation of CT led to “in-out-in” screws, which resulted in neurapraxia. 

In our study, we used the technique described by Matta and colleagues for placement of the screws and performed a postoperative CT to evaluate screw placement and to assess pelvic reduction.⁷ We had a high penetration rate using CT, which increased with better resolution, even though none of the radiographs showed any obvious evidence of misplacement of the screws. Ebraheim and colleagues⁶ described the relationship of the S1 nerve root in its neural foramen and found it to be approximately 8.7 mm inferior and 7.8 mm medial to the starting point for a pedicle screw. Given these numbers, it is possible that a large amount of skiving can be tolerated contingent on an adequate reduction of the SI joint. 

Because of our high rates of skiving and low rates of neurologic deficit, a new “safe zone” for screw insertion can be expanded to include skiving of the S1 neural foramen up to 3 mm without fear of nerve root injury. However, drilling and screw insertion at higher speeds can also cause neurologic injury secondary to thermal injury or soft tissue being caught up in a rotating drill/screw. 

Evaluation of placement of percutaneous SI screw placement in our study resulted in neural foramen penetration in 43% of SI screws, which is higher than other studies.^14,19,20 Our study showed that screw penetration up to 2 mm does not correlate with neurologic deficit. Iatrogenic neurologic deficit secondary to perforation of the foramina occurred in only 1 patient. Penetration of the foramina in all cases was in the superior portion of the foramen. We propose that there is a safe zone within the S1 neural foramen, and small amounts of penetration in the superior one-third of the foramen on axial CT images do not correlate with neurologic deficit. This potential safe zone is predicated on adequate reduction of the SI joint. 

Neural foramen penetration shown on postoperative CT does not necessarily correlate with neurologic deficit. A postoperative CT is not indicated unless there are findings of a postoperative nerve injury. Our ideal screw placement skives the superior S1 foramen allowing for a larger screw diameter in a safe zone.

CT-guided placement has been proposed; however, concerns about radiation exposure, cost, and feasibility with similar outcomes compared with fluoroscopic-guided screw placement has resulted in its falling out of favor.

Iatrogenic nerve injuries are reported to occur in 0% to 6% of all percutaneous SI screw placement.^14,21 Risk factors for iatrogenic nerve injury while using fluoroscopic guidance include sacral morphologic abnormalities, presence of intestinal gas, or contrast.²² Although these may be minimized with proper use of fluoroscopy, obtaining anatomic reduction as well as a thorough understanding of the pelvic morphology, the surgeon must be prepared to obtain further studies, such as a CT scan, if there is postoperative neurologic deficit.

Based on our findings, we do not routinely obtain a postoperative CT for SI screw placement, unless there is concern for malreduction or there is neurologic deficit. We also believe that up to 2 mm of foramen penetration is safe and does not result in neurologic deficit.

Pelvic injuries account for 3% of all skeletal fractures.¹ Injury to the sacroiliac (SI) joint is frequently associated with unstable pelvic ring fractures, which are potentially life-threatening injuries. Surgical fixation of these injuries is preferred to nonoperative treatment given the potential for improved reduction and early mobilization and weight-bearing, thereby decreasing perioperative morbidity and improving functional outcome.²

The classic method of surgical fixation of the SI joint consisted of open reduction and internal fixation. This method carried a substantial risk for large dissection, iatrogenic nerve injury, and increased blood loss to the already traumatized patient.³ Percutaneous fixation allows for a shorter operating time, decreased soft-tissue stripping, and decreased blood loss compared with a traditional open procedure.⁴ However, posterior pelvic anatomy is complex and variable, and reports have found screw misplacements as high as 24%⁵ and neurologic complication rates up to 18%.^6-9 

Various imaging modalities, including fluoroscopy,⁵ computed tomography (CT),^6-7 fluoroscopic CT, and computer-assisted techniques^5,9 have been used to achieve proper screw placement. Conventional fluoroscopy is the standard for intraoperative screw placement. However, acceptable reduction of the SI joint and proper implantation of the screws without perforation of the neural foramina is challenging, especially when coupled with difficulties of fluoroscopic imaging and variations in pelvic anatomy. 

Sacral dysplasia has been reported to occur in up to 20% to 40% of the population and has significant implications in patients indicated for iliosacral screw placement.¹⁰ Incorrect placement of iliosacral screws may result in iatrogenic neurovascular complications.^11-13 Malpositioned screws using fluoroscopic guidance have been reported in 2% to 15% of patients with an incidence of neurologic compromise between 0.5% and 7.7%. As little as 4° of misdirection can result in damage to neurovascular structures.¹⁴

At our institution, we routinely obtained postoperative CT to evaluate the placement of SI screws. The objective of this retrospective study is to evaluate the rate of revision surgery of percutaneous SI screw fixation, to determine whether CT is an accurate tool for evaluation of the reduction and the need for revision surgery, and to decide if any violation of the neural foramina is safe.

Materials and Methods

After institutional review board approval, we retrospectively reviewed and evaluated medical records and radiographs of all patients who sustained unstable pelvic ring fractures between July 1, 2005, and June 30, 2010. We identified all patients who were treated with closed reductions and percutaneous iliosacral screw fixation, according to the method described by Routt in 1995.⁴ We excluded all pelvic fractures in patients who underwent open reduction for the posterior injury or did not have percutaneous SI screws placed, those with spinal injury, and those without follow-up. Of the 46 patients who met the inclusion criteria were 26 men and 20 women with a mean age of 42 years (range, 16 to 73 years). Motor vehicle accidents accounted for 13 cases; 19 were crush injuries and 14 were falls from height. Seventeen patients (37%) met the radiographic criteria for sacral dysmorphism. Forty-two of the 46 patients were polytrauma patients with associated musculoskeletal injuries and/or abdominal, chest, or head injuries.

Six patients presented with some neurologic deficit at the time of injury; all fractures were closed. The initial imaging study included plain anteroposterior (AP), inlet, and outlet radiographs of the pelvis and a pelvic CT scan. Using the classification of Young and Burgess,¹⁵ there were 3 vertical shear injuries, 13 lateral compression–type injuries, 17 anterior-posterior–type injuries, 7 sacral fractures, and 6 combination- or unclassifiable-type pelvic injuries. Of the sacral fractures, there were 3 Denis zone 1, 3 Denis zone 2, and 1 Denis zone 3. 

The pelvic CT scan included the entire pelvis from the ilium to the ischial tuberosities. Each scan consisted of either a 5.0-mm or a 2.5-mm sequential axial image. A picture archiving and communication system (PACS) workstation using Centricity version 2.1 (GE Medical Systems, Waukesha, Wisconsin) was used to analyze each scan with a bone algorithm. On PACS, each initial displacement was characterized by the amount of SI joint widening at the level of the S1 and was measured using digital calipers.   

Surgery

Mean time to surgery was 4 days (range, 2 to 15 days) after the injury. A total of 51 SI screws were implanted in 46 patients. We achieved closed reduction of the posterior pelvic ring by various techniques, including compression with percutaneous partially threaded screw fixation. In the cases in which the posterior ring lesion was associated with a pure pubic symphysis disruption, the anterior pelvis was initially reduced and stabilized with small-fragment plate fixation (Synthes, Inc, Paoli, Pennsylvania). The posterior complex was stabilized with 1 screw in 41 patients, 2 cases required a transiliac screw, and 2 screws (S1 and S2) were placed in each of the remaining 3 cases. Definitive stabilization of the posterior pelvis was achieved with percutaneous, partially threaded 7.3- or 7.5-mm–diameter cannulated screws (Synthes, Inc, and Zimmer Inc, Warsaw, Indiana, respectively) in 42 fractures and 6.5-mm screws (Synthes, Inc) in 4 fractures. In 11 cases where the fracture was through the sacrum, fully threaded cannulated screws were used to avoid compression. Screw insertion was performed under fluoroscopic guidance with inlet, outlet, and lateral sacral views. One of 2 fellowship-trained trauma surgeons performed the surgeries. Rehabilitation plans were customized to each patient based on concomitant injuries. 

Postoperative Assessment

AP, lateral sacral, and inlet and outlet postoperative radiographs were taken in all cases within 24 hours after surgery. Pelvic CT was also obtained within 24 hours of surgery to review reduction and screw placement.

Using the measurement tool on the PACS system, we measured the penetration of the screw into the foramen. Screws were graded as intraosseous (completely contained within the sacral bone), skived (less than 2 mm of partial penetration into the S1 foramen), or extruded (the screw not contained by the bone). Screw penetration of the S1 was evaluated on the radiographic images as well as the axial images of the CT scans.

After surgery, the senior orthopedic resident and attending surgeon performed and documented detailed neurologic evaluations. They reviewed the medical record for neurologic deficit following surgical fixation.   

Results

The mean follow-up time was 12 months (range, 8 months to 2 years). Two patients expired secondary to associated injuries. There were no early deaths related to the pelvic surgery. Stable fixation, including bone or ligamentous healing, as well as full weight-bearing status, was noted in every case. No case exhibited loss of reduction or implant failure or infection.

According to Matta’s criteria of anatomic reduction within 1 cm, all patients were found to have satisfactory reductions.⁷ Six of 46 patients had documented preoperative neurologic deficits. After percutaneous screw fixation, 10 of 46 patients had postoperative neurologic deficit, 2 of which were unchanged from preoperative evaluation. Of the 8 patients with new/altered postoperative neurologic deficit, CT showed neural foramen penetration greater than 2.1 mm in only 2 patients. Both patients underwent screw revision, resulting in improved neurologic deficit. The remaining 4 patients did not have foramen penetration and improved their neurologic function over the course of 2 weeks with return to presurgical status by 6 weeks without necessitating screw removal.

Twenty-three of the 51 screws (45%) had some violation of the S1 foramen on the CT. There were 17 patients with dysmorphic sacrums in which 21 S1 screws were placed. Eleven of  21 (52%) screws showed some penetration of the S1 foramen on CT. There were 29 patients with normal sacral morphology in which 30 S1 screws were placed. Twelve of 30 (40%) screws penetrated the S1 foramen. All violations were in the superior one-third position of the foramen. Two of 46 (4%; 1 with dysmorphism, 1 without) had a new neurologic deficit associated with the surgery (Table). CT showed sacral foramen penetration, and both screws were revised with a better neurologic examination.

High-resolution CTs were obtained in 32 patients, while 14 patients underwent the standard 5.0-mm–cut CTs. Of the 32 patients in which a 2.5-mm high-resolution CT was obtained, 20 (62.5%) had evidence of screw penetration (Figures 1, 2). All violations of the S1 neural foramen were in the superior portion of the foramen. 

When compared with patients who had a 5.0-mm CT, the patients who underwent a high-resolution CT were more likely to show neural foramen penetration (P = .3). The average screw penetration into the S1 neural foramen measured 3.3 mm (range, 1.6-5.7 mm) in dysmorphic sacrum and 2.7 mm  (range, 1.4-7 mm) in normal sacrum. However, in our study, any foramen penetration of less than 2.1 mm on CT did not result in neurologic deficit.  

Discussion

Pelvic fractures are fairly common and represent approximately 5% of all trauma admissions and 3% of all skeletal fractures nationwide.¹ The current treatment for SI disruption is either nonoperative or operative. Surgical fixation is technically demanding and surgeons often need a long learning curve to acquire the demanding technique because of the limitations of radiographic visualization of the relevant landmarks.¹⁶

Letournel¹⁷ developed the technique for iliosacral screw fixation for the treatment of posterior pelvic ring injuries, where 1 or 2 large screws (6.5-7.3 mm in diameter) are inserted under fluoroscopic guidance through the ilium, across the SI articulation, and into the superior sacral vertebral bodies using percutaneous techniques. Currently, the standard procedure to accomplish the percutaneous placement of iliosacral screws derives mainly from the technique described by Matta with the C-arm fluoroscopy visualizing the pelvis in 3 views: strict AP, inlet, and outlet views.⁷

Routt and colleagues⁴ recommend a strict lateral view of the sacrum, particularly when crossing the narrow zone of the sacral alar. They reported high union rates and accurate placement of the screws.⁴ There are limitations to the use of biplanar fluoroscopy because the intraoperative images are not orthogonal, with the average arc (67º) between the ideal inlet and outlet. However, because of the variability in sacral anatomy, CT guidance was recommended by others.^2,6,8,18 Operating in a CT suite had other complications. Misinterpretation of CT led to “in-out-in” screws, which resulted in neurapraxia. 

In our study, we used the technique described by Matta and colleagues for placement of the screws and performed a postoperative CT to evaluate screw placement and to assess pelvic reduction.⁷ We had a high penetration rate using CT, which increased with better resolution, even though none of the radiographs showed any obvious evidence of misplacement of the screws. Ebraheim and colleagues⁶ described the relationship of the S1 nerve root in its neural foramen and found it to be approximately 8.7 mm inferior and 7.8 mm medial to the starting point for a pedicle screw. Given these numbers, it is possible that a large amount of skiving can be tolerated contingent on an adequate reduction of the SI joint. 

Because of our high rates of skiving and low rates of neurologic deficit, a new “safe zone” for screw insertion can be expanded to include skiving of the S1 neural foramen up to 3 mm without fear of nerve root injury. However, drilling and screw insertion at higher speeds can also cause neurologic injury secondary to thermal injury or soft tissue being caught up in a rotating drill/screw. 

Evaluation of placement of percutaneous SI screw placement in our study resulted in neural foramen penetration in 43% of SI screws, which is higher than other studies.^14,19,20 Our study showed that screw penetration up to 2 mm does not correlate with neurologic deficit. Iatrogenic neurologic deficit secondary to perforation of the foramina occurred in only 1 patient. Penetration of the foramina in all cases was in the superior portion of the foramen. We propose that there is a safe zone within the S1 neural foramen, and small amounts of penetration in the superior one-third of the foramen on axial CT images do not correlate with neurologic deficit. This potential safe zone is predicated on adequate reduction of the SI joint. 

Neural foramen penetration shown on postoperative CT does not necessarily correlate with neurologic deficit. A postoperative CT is not indicated unless there are findings of a postoperative nerve injury. Our ideal screw placement skives the superior S1 foramen allowing for a larger screw diameter in a safe zone.

CT-guided placement has been proposed; however, concerns about radiation exposure, cost, and feasibility with similar outcomes compared with fluoroscopic-guided screw placement has resulted in its falling out of favor.

Iatrogenic nerve injuries are reported to occur in 0% to 6% of all percutaneous SI screw placement.^14,21 Risk factors for iatrogenic nerve injury while using fluoroscopic guidance include sacral morphologic abnormalities, presence of intestinal gas, or contrast.²² Although these may be minimized with proper use of fluoroscopy, obtaining anatomic reduction as well as a thorough understanding of the pelvic morphology, the surgeon must be prepared to obtain further studies, such as a CT scan, if there is postoperative neurologic deficit.

Based on our findings, we do not routinely obtain a postoperative CT for SI screw placement, unless there is concern for malreduction or there is neurologic deficit. We also believe that up to 2 mm of foramen penetration is safe and does not result in neurologic deficit.

Clinical question: When hallway boarding is required, do patients prefer inpatient units over the ED?

Background: ED crowding is associated with patient dissatisfaction, ambulance diversion, delays in care, medical errors, and higher mortality rates. Strategies to alleviate the problem of boarding admitted patients in the ED can include relocation to inpatient hallways while awaiting a regular hospital bed. Traditional objections to inpatient hallway boarding include concerns regarding patient satisfaction and safety.

Study design: Structured telephone survey.

Setting: Suburban, university-based, teaching hospital.

Synopsis: Patients who required boarding in the ED hallway after hospital admission were eligible for inpatient hallway boarding according to the institutional protocol, which screens for those with only mild to moderate comorbidities. Of 110 consecutive patients contacted who experienced both ED and inpatient hallway boarding, 105 consented to participate in a tested telephone survey instrument.

The overall preferred location was inpatient hallways for 85% (95% CI 75-90) of respondents. Comparing ED boarding to inpatient hallway boarding, respondents preferred inpatient boarding with regard to staff availability (84%), safety (83%), confidentiality (82%), and comfort (79%).

Study results were subject to non-response bias, because working telephone numbers were required for study inclusion, as well as recall bias, because the survey was conducted within several months after discharge. This study’s results are based on actual patient experiences, whereas prior literature relied on patients to hypothesize the preferred environment after experiencing only ED hallway boarding to predict satisfaction.

Bottom line: Boarding in inpatient hallways was associated with higher patient satisfaction compared with ED hallway boarding.

Citation: Viccellio P, Zito JA, Sayage V, et al. Patients overwhelmingly prefer inpatient boarding to emergency department boarding [published online ahead of print September 21, 2013].

Clinical question: When hallway boarding is required, do patients prefer inpatient units over the ED?

Background: ED crowding is associated with patient dissatisfaction, ambulance diversion, delays in care, medical errors, and higher mortality rates. Strategies to alleviate the problem of boarding admitted patients in the ED can include relocation to inpatient hallways while awaiting a regular hospital bed. Traditional objections to inpatient hallway boarding include concerns regarding patient satisfaction and safety.

Study design: Structured telephone survey.

Setting: Suburban, university-based, teaching hospital.

Synopsis: Patients who required boarding in the ED hallway after hospital admission were eligible for inpatient hallway boarding according to the institutional protocol, which screens for those with only mild to moderate comorbidities. Of 110 consecutive patients contacted who experienced both ED and inpatient hallway boarding, 105 consented to participate in a tested telephone survey instrument.

The overall preferred location was inpatient hallways for 85% (95% CI 75-90) of respondents. Comparing ED boarding to inpatient hallway boarding, respondents preferred inpatient boarding with regard to staff availability (84%), safety (83%), confidentiality (82%), and comfort (79%).

Study results were subject to non-response bias, because working telephone numbers were required for study inclusion, as well as recall bias, because the survey was conducted within several months after discharge. This study’s results are based on actual patient experiences, whereas prior literature relied on patients to hypothesize the preferred environment after experiencing only ED hallway boarding to predict satisfaction.

Bottom line: Boarding in inpatient hallways was associated with higher patient satisfaction compared with ED hallway boarding.

Citation: Viccellio P, Zito JA, Sayage V, et al. Patients overwhelmingly prefer inpatient boarding to emergency department boarding [published online ahead of print September 21, 2013].

Clinical question: When hallway boarding is required, do patients prefer inpatient units over the ED?

Background: ED crowding is associated with patient dissatisfaction, ambulance diversion, delays in care, medical errors, and higher mortality rates. Strategies to alleviate the problem of boarding admitted patients in the ED can include relocation to inpatient hallways while awaiting a regular hospital bed. Traditional objections to inpatient hallway boarding include concerns regarding patient satisfaction and safety.

Study design: Structured telephone survey.

Setting: Suburban, university-based, teaching hospital.

Synopsis: Patients who required boarding in the ED hallway after hospital admission were eligible for inpatient hallway boarding according to the institutional protocol, which screens for those with only mild to moderate comorbidities. Of 110 consecutive patients contacted who experienced both ED and inpatient hallway boarding, 105 consented to participate in a tested telephone survey instrument.

The overall preferred location was inpatient hallways for 85% (95% CI 75-90) of respondents. Comparing ED boarding to inpatient hallway boarding, respondents preferred inpatient boarding with regard to staff availability (84%), safety (83%), confidentiality (82%), and comfort (79%).

Study results were subject to non-response bias, because working telephone numbers were required for study inclusion, as well as recall bias, because the survey was conducted within several months after discharge. This study’s results are based on actual patient experiences, whereas prior literature relied on patients to hypothesize the preferred environment after experiencing only ED hallway boarding to predict satisfaction.

Bottom line: Boarding in inpatient hallways was associated with higher patient satisfaction compared with ED hallway boarding.

Citation: Viccellio P, Zito JA, Sayage V, et al. Patients overwhelmingly prefer inpatient boarding to emergency department boarding [published online ahead of print September 21, 2013].

Clinical question: What factors determine rates of readmission after major surgery?

Background: Reducing hospital readmission rates has become a national priority. The U.S. patterns for surgical readmissions are unknown, as are the specific structural and quality characteristics of hospitals associated with lower surgical readmission rates.

Study design: Retrospective study of national Medicare data was used to calculate 30-day readmission rates for six major surgical procedures.

Setting: U.S. Hospitals, 2009-2010.

Synopsis: Six major surgical procedures were tracked by Medicare data, with 479,471 discharges from 3,004 hospitals. Structural characteristics included hospital size, teaching status, region, ownership, and proportion of patients living below the federal poverty line. Three well-established measures of surgical quality were used: the HQA surgical score, procedure volume, and 30-day mortality.

Hospitals in the highest quartile for surgical volume had a significantly lower readmission rate. Additionally, hospitals with the lowest surgical mortality rates had significantly lower readmission rates. Interestingly, high adherence to reported surgical process measures was only marginally associated with reduced admission rates. Prior studies have also shown inconsistent relationship between HQA surgical score and mortality.

Limitations to this study include inability to account for factors not captured by billing codes and the focus on a Medicare population.

Bottom line: Surgical readmission rates are associated with measures of surgical quality, specifically procedural volume and mortality.

Citation: Tsai TC, Joynt KE, Orav EJ, Gawande AA, Jha AK. Variation in surgical-readmission rates and quality of hospital care. 2013;369(12):1134-1142.

Clinical question: What factors determine rates of readmission after major surgery?

Background: Reducing hospital readmission rates has become a national priority. The U.S. patterns for surgical readmissions are unknown, as are the specific structural and quality characteristics of hospitals associated with lower surgical readmission rates.

Study design: Retrospective study of national Medicare data was used to calculate 30-day readmission rates for six major surgical procedures.

Setting: U.S. Hospitals, 2009-2010.

Synopsis: Six major surgical procedures were tracked by Medicare data, with 479,471 discharges from 3,004 hospitals. Structural characteristics included hospital size, teaching status, region, ownership, and proportion of patients living below the federal poverty line. Three well-established measures of surgical quality were used: the HQA surgical score, procedure volume, and 30-day mortality.

Hospitals in the highest quartile for surgical volume had a significantly lower readmission rate. Additionally, hospitals with the lowest surgical mortality rates had significantly lower readmission rates. Interestingly, high adherence to reported surgical process measures was only marginally associated with reduced admission rates. Prior studies have also shown inconsistent relationship between HQA surgical score and mortality.

Limitations to this study include inability to account for factors not captured by billing codes and the focus on a Medicare population.

Bottom line: Surgical readmission rates are associated with measures of surgical quality, specifically procedural volume and mortality.

Citation: Tsai TC, Joynt KE, Orav EJ, Gawande AA, Jha AK. Variation in surgical-readmission rates and quality of hospital care. 2013;369(12):1134-1142.

Clinical question: What factors determine rates of readmission after major surgery?

Background: Reducing hospital readmission rates has become a national priority. The U.S. patterns for surgical readmissions are unknown, as are the specific structural and quality characteristics of hospitals associated with lower surgical readmission rates.

Study design: Retrospective study of national Medicare data was used to calculate 30-day readmission rates for six major surgical procedures.

Setting: U.S. Hospitals, 2009-2010.

Synopsis: Six major surgical procedures were tracked by Medicare data, with 479,471 discharges from 3,004 hospitals. Structural characteristics included hospital size, teaching status, region, ownership, and proportion of patients living below the federal poverty line. Three well-established measures of surgical quality were used: the HQA surgical score, procedure volume, and 30-day mortality.

Hospitals in the highest quartile for surgical volume had a significantly lower readmission rate. Additionally, hospitals with the lowest surgical mortality rates had significantly lower readmission rates. Interestingly, high adherence to reported surgical process measures was only marginally associated with reduced admission rates. Prior studies have also shown inconsistent relationship between HQA surgical score and mortality.

Limitations to this study include inability to account for factors not captured by billing codes and the focus on a Medicare population.

Bottom line: Surgical readmission rates are associated with measures of surgical quality, specifically procedural volume and mortality.

Citation: Tsai TC, Joynt KE, Orav EJ, Gawande AA, Jha AK. Variation in surgical-readmission rates and quality of hospital care. 2013;369(12):1134-1142.

Clinical question: Is continuity of care related to preventable hospitalizations among older adults?

Background: Preventable hospitalizations cost approximately $25 billion annually in the U.S. The relationship between continuity of care and the risk of preventable hospitalization is unknown.

Study design: Retrospective cohort study.

Setting: Random sample of fee-for-service Medicare beneficiaries, for ambulatory visits and hospital admissions.

Synopsis: This study examined 3.2 million Medicare beneficiaries using 2008-2010 claims data to measure continuity and the first preventable hospitalization. The Prevention Quality Indicators definitions and technical specifications from the Agency for Healthcare Research and Quality were used to identify preventable hospitalizations. Both the continuity of care score and usual provider continuity score were used to calculate continuity metrics. Baseline risk of preventable hospitalization included age, sex, race, Medicaid dual-eligible status, and residential zip code.

During a two-year period, 12.6% of patients had a preventable hospitalization. After adjusting for variables, a 0.1 increase in continuity of care was associated with about a 2% lower rate of preventable hospitalization. Interestingly, continuity of care was not related to mortality rates.

This study extends prior research associating continuity of care with reduced rate of hospitalization; however, the associations found cannot assert a causal relationship. This study used coding practices that vary throughout the country, included only older fee-for-service Medicare beneficiaries, and could not verify why some patients had higher continuity of care. The authors suggest that efforts to strengthen physician-patient relationships through high-quality primary care will deter some hospital admissions.

Bottom line: Higher continuity of ambulatory care is associated with lower preventable hospitalizations in Medicare beneficiaries.

Citation: Nyweide DJ, Anthony DL, Bynum JP, et al. Continuity of care and the risk of preventable hospitalization in older adults. 2013;173(20):1879-1885.

Clinical question: Is continuity of care related to preventable hospitalizations among older adults?

Background: Preventable hospitalizations cost approximately $25 billion annually in the U.S. The relationship between continuity of care and the risk of preventable hospitalization is unknown.

Study design: Retrospective cohort study.

Setting: Random sample of fee-for-service Medicare beneficiaries, for ambulatory visits and hospital admissions.

Synopsis: This study examined 3.2 million Medicare beneficiaries using 2008-2010 claims data to measure continuity and the first preventable hospitalization. The Prevention Quality Indicators definitions and technical specifications from the Agency for Healthcare Research and Quality were used to identify preventable hospitalizations. Both the continuity of care score and usual provider continuity score were used to calculate continuity metrics. Baseline risk of preventable hospitalization included age, sex, race, Medicaid dual-eligible status, and residential zip code.

During a two-year period, 12.6% of patients had a preventable hospitalization. After adjusting for variables, a 0.1 increase in continuity of care was associated with about a 2% lower rate of preventable hospitalization. Interestingly, continuity of care was not related to mortality rates.

This study extends prior research associating continuity of care with reduced rate of hospitalization; however, the associations found cannot assert a causal relationship. This study used coding practices that vary throughout the country, included only older fee-for-service Medicare beneficiaries, and could not verify why some patients had higher continuity of care. The authors suggest that efforts to strengthen physician-patient relationships through high-quality primary care will deter some hospital admissions.

Bottom line: Higher continuity of ambulatory care is associated with lower preventable hospitalizations in Medicare beneficiaries.

Citation: Nyweide DJ, Anthony DL, Bynum JP, et al. Continuity of care and the risk of preventable hospitalization in older adults. 2013;173(20):1879-1885.

Clinical question: Is continuity of care related to preventable hospitalizations among older adults?

Background: Preventable hospitalizations cost approximately $25 billion annually in the U.S. The relationship between continuity of care and the risk of preventable hospitalization is unknown.

Study design: Retrospective cohort study.

Setting: Random sample of fee-for-service Medicare beneficiaries, for ambulatory visits and hospital admissions.

Synopsis: This study examined 3.2 million Medicare beneficiaries using 2008-2010 claims data to measure continuity and the first preventable hospitalization. The Prevention Quality Indicators definitions and technical specifications from the Agency for Healthcare Research and Quality were used to identify preventable hospitalizations. Both the continuity of care score and usual provider continuity score were used to calculate continuity metrics. Baseline risk of preventable hospitalization included age, sex, race, Medicaid dual-eligible status, and residential zip code.

During a two-year period, 12.6% of patients had a preventable hospitalization. After adjusting for variables, a 0.1 increase in continuity of care was associated with about a 2% lower rate of preventable hospitalization. Interestingly, continuity of care was not related to mortality rates.

This study extends prior research associating continuity of care with reduced rate of hospitalization; however, the associations found cannot assert a causal relationship. This study used coding practices that vary throughout the country, included only older fee-for-service Medicare beneficiaries, and could not verify why some patients had higher continuity of care. The authors suggest that efforts to strengthen physician-patient relationships through high-quality primary care will deter some hospital admissions.

Bottom line: Higher continuity of ambulatory care is associated with lower preventable hospitalizations in Medicare beneficiaries.

Citation: Nyweide DJ, Anthony DL, Bynum JP, et al. Continuity of care and the risk of preventable hospitalization in older adults. 2013;173(20):1879-1885.

Clinical question: What effect does a hospitalist-staffed, post-discharge clinic have on time to first post-hospitalization visit?

Background: Hospital discharge is a well-recognized care transition that can leave patients vulnerable to morbidity and re-hospitalization. Limited primary care access can hamper complex post-hospital follow-up. Discharge clinic models staffed by hospitalists have been developed to mitigate access issues, but research is lacking to describe their characteristics and benefits.

Study design: Single-center, prospective, observational database review.

Setting: Large, academic primary care practice affiliated with an academic medical center.

Synopsis: Between 2009 and 2011, this hospitalist-staffed, post-discharge clinic saw 596 patients, while the affiliated, large primary care practice saw 10,839 patients. Patients utilizing the hospitalist discharge clinic were more likely to be black (39% vs. 29%, <0.001) and to receive primary care from resident clinics (40% vs. 21%, <0.001). The median duration from hospital discharge to the first clinic visit was shorter for the post-discharge clinic (8.45 ± 0.43 days, <0.001).

The number of radiology and laboratory tests performed at the first post-discharge clinic visit showed similar patterns between the hospitalist discharge clinic and the primary care practice. Study design and size did not permit comparisons of readmission rates or mortality from time of discharge and also precluded evaluation of interventions on discharge-related medication errors or response time to outstanding test results.

Bottom line: A hospitalist-staffed, post-discharge clinic was associated with shorter time to first post-discharge visit, especially for patients who are black and receive primary care from resident clinics.

Citation: Doctoroff L, Nijhawan A, McNally D, Vanka A, Yu R, Mukamal KJ. The characteristics and impact of a hospitalist-staffed post-discharge clinic. 2013;126(11):1016.e9-1016.e15.

Clinical question: What effect does a hospitalist-staffed, post-discharge clinic have on time to first post-hospitalization visit?

Background: Hospital discharge is a well-recognized care transition that can leave patients vulnerable to morbidity and re-hospitalization. Limited primary care access can hamper complex post-hospital follow-up. Discharge clinic models staffed by hospitalists have been developed to mitigate access issues, but research is lacking to describe their characteristics and benefits.

Study design: Single-center, prospective, observational database review.

Setting: Large, academic primary care practice affiliated with an academic medical center.

Synopsis: Between 2009 and 2011, this hospitalist-staffed, post-discharge clinic saw 596 patients, while the affiliated, large primary care practice saw 10,839 patients. Patients utilizing the hospitalist discharge clinic were more likely to be black (39% vs. 29%, <0.001) and to receive primary care from resident clinics (40% vs. 21%, <0.001). The median duration from hospital discharge to the first clinic visit was shorter for the post-discharge clinic (8.45 ± 0.43 days, <0.001).

The number of radiology and laboratory tests performed at the first post-discharge clinic visit showed similar patterns between the hospitalist discharge clinic and the primary care practice. Study design and size did not permit comparisons of readmission rates or mortality from time of discharge and also precluded evaluation of interventions on discharge-related medication errors or response time to outstanding test results.

Bottom line: A hospitalist-staffed, post-discharge clinic was associated with shorter time to first post-discharge visit, especially for patients who are black and receive primary care from resident clinics.

Citation: Doctoroff L, Nijhawan A, McNally D, Vanka A, Yu R, Mukamal KJ. The characteristics and impact of a hospitalist-staffed post-discharge clinic. 2013;126(11):1016.e9-1016.e15.

Clinical question: What effect does a hospitalist-staffed, post-discharge clinic have on time to first post-hospitalization visit?

Background: Hospital discharge is a well-recognized care transition that can leave patients vulnerable to morbidity and re-hospitalization. Limited primary care access can hamper complex post-hospital follow-up. Discharge clinic models staffed by hospitalists have been developed to mitigate access issues, but research is lacking to describe their characteristics and benefits.

Study design: Single-center, prospective, observational database review.

Setting: Large, academic primary care practice affiliated with an academic medical center.

Synopsis: Between 2009 and 2011, this hospitalist-staffed, post-discharge clinic saw 596 patients, while the affiliated, large primary care practice saw 10,839 patients. Patients utilizing the hospitalist discharge clinic were more likely to be black (39% vs. 29%, <0.001) and to receive primary care from resident clinics (40% vs. 21%, <0.001). The median duration from hospital discharge to the first clinic visit was shorter for the post-discharge clinic (8.45 ± 0.43 days, <0.001).

The number of radiology and laboratory tests performed at the first post-discharge clinic visit showed similar patterns between the hospitalist discharge clinic and the primary care practice. Study design and size did not permit comparisons of readmission rates or mortality from time of discharge and also precluded evaluation of interventions on discharge-related medication errors or response time to outstanding test results.

Bottom line: A hospitalist-staffed, post-discharge clinic was associated with shorter time to first post-discharge visit, especially for patients who are black and receive primary care from resident clinics.

Citation: Doctoroff L, Nijhawan A, McNally D, Vanka A, Yu R, Mukamal KJ. The characteristics and impact of a hospitalist-staffed post-discharge clinic. 2013;126(11):1016.e9-1016.e15.

Clinical question: Does the addition of pentoxifylline to prednisolone improve six-month mortality compared to prednisolone alone in patients with severe alcoholic hepatitis?

Background: Prednisolone improves liver function and reduces inflammation in patients with alcoholic hepatitis. Pentoxifylline appears to have a protective effect against hepatorenal syndrome in patients with severe alcoholic hepatitis. The medications have different mechanisms of action; therefore, the researchers hypothesized that the combination of medication would improve outcomes.

Study design: Multi-center, randomized, double-blinded clinical trial.

Setting: One Belgian and 23 French hospitals, from December 2007 to October 2010.

Synopsis: This study randomized 270 patients to receive either prednisolone and pentoxifylline or prednisolone and placebo for 28 days. Acute alcoholic hepatitis was defined by a positive biopsy, onset of jaundice three months prior to the study, and a Maddrey’s discriminant function score of >32. All patients were assessed for response to treatment using the Lille model at seven days of treatment, occurrence of hepatorenal syndrome, and survival at six months.

Results showed no significant difference in treatment response, alcohol relapse, death, time to death, or occurrence of hepatorenal syndrome between the two treatment groups; however, there were fewer episodes of hepatorenal syndrome in the pentoxifylline group.

Patients considered responders by the Lille model and those with lower Model for End-Stage Liver Disease scores had improved mortality. Patients treated with pentoxifylline had lower rates of hepatorenal syndrome at one month but no difference by six months. Patients with a lower Lille score had significantly less incidence of hepatorenal syndrome. The study may be underpowered to accurately determine outcomes other than six-month survival.

Bottom line: Adding pentoxifylline to prednisolone does not improve six-month survival in severe alcoholic hepatitis compared to prednisolone alone.

Citation: Mathurin P, Louvet A, Duhamel A, et al. Prednisolone with vs without pentoxifylline and survival of patients with severe alcoholic hepatitis: a randomized clinical trial. 2013;310(10):1033-1041.

Clinical question: Does the addition of pentoxifylline to prednisolone improve six-month mortality compared to prednisolone alone in patients with severe alcoholic hepatitis?

Background: Prednisolone improves liver function and reduces inflammation in patients with alcoholic hepatitis. Pentoxifylline appears to have a protective effect against hepatorenal syndrome in patients with severe alcoholic hepatitis. The medications have different mechanisms of action; therefore, the researchers hypothesized that the combination of medication would improve outcomes.

Study design: Multi-center, randomized, double-blinded clinical trial.

Setting: One Belgian and 23 French hospitals, from December 2007 to October 2010.

Synopsis: This study randomized 270 patients to receive either prednisolone and pentoxifylline or prednisolone and placebo for 28 days. Acute alcoholic hepatitis was defined by a positive biopsy, onset of jaundice three months prior to the study, and a Maddrey’s discriminant function score of >32. All patients were assessed for response to treatment using the Lille model at seven days of treatment, occurrence of hepatorenal syndrome, and survival at six months.

Results showed no significant difference in treatment response, alcohol relapse, death, time to death, or occurrence of hepatorenal syndrome between the two treatment groups; however, there were fewer episodes of hepatorenal syndrome in the pentoxifylline group.

Patients considered responders by the Lille model and those with lower Model for End-Stage Liver Disease scores had improved mortality. Patients treated with pentoxifylline had lower rates of hepatorenal syndrome at one month but no difference by six months. Patients with a lower Lille score had significantly less incidence of hepatorenal syndrome. The study may be underpowered to accurately determine outcomes other than six-month survival.

Bottom line: Adding pentoxifylline to prednisolone does not improve six-month survival in severe alcoholic hepatitis compared to prednisolone alone.

Citation: Mathurin P, Louvet A, Duhamel A, et al. Prednisolone with vs without pentoxifylline and survival of patients with severe alcoholic hepatitis: a randomized clinical trial. 2013;310(10):1033-1041.

Clinical question: Does the addition of pentoxifylline to prednisolone improve six-month mortality compared to prednisolone alone in patients with severe alcoholic hepatitis?

Background: Prednisolone improves liver function and reduces inflammation in patients with alcoholic hepatitis. Pentoxifylline appears to have a protective effect against hepatorenal syndrome in patients with severe alcoholic hepatitis. The medications have different mechanisms of action; therefore, the researchers hypothesized that the combination of medication would improve outcomes.

Study design: Multi-center, randomized, double-blinded clinical trial.

Setting: One Belgian and 23 French hospitals, from December 2007 to October 2010.

Synopsis: This study randomized 270 patients to receive either prednisolone and pentoxifylline or prednisolone and placebo for 28 days. Acute alcoholic hepatitis was defined by a positive biopsy, onset of jaundice three months prior to the study, and a Maddrey’s discriminant function score of >32. All patients were assessed for response to treatment using the Lille model at seven days of treatment, occurrence of hepatorenal syndrome, and survival at six months.

Results showed no significant difference in treatment response, alcohol relapse, death, time to death, or occurrence of hepatorenal syndrome between the two treatment groups; however, there were fewer episodes of hepatorenal syndrome in the pentoxifylline group.

Patients considered responders by the Lille model and those with lower Model for End-Stage Liver Disease scores had improved mortality. Patients treated with pentoxifylline had lower rates of hepatorenal syndrome at one month but no difference by six months. Patients with a lower Lille score had significantly less incidence of hepatorenal syndrome. The study may be underpowered to accurately determine outcomes other than six-month survival.

Bottom line: Adding pentoxifylline to prednisolone does not improve six-month survival in severe alcoholic hepatitis compared to prednisolone alone.

Citation: Mathurin P, Louvet A, Duhamel A, et al. Prednisolone with vs without pentoxifylline and survival of patients with severe alcoholic hepatitis: a randomized clinical trial. 2013;310(10):1033-1041.

ANSWER

The correct answer is impetigo (choice “c”), a superficial infection usually caused by a combination of staph and strep organisms.

Psoriasis (choice “a”) would have presented with white, tenacious scaling and would not have been acute in onset.

Eczema (choice “b”) is definitely possible, but the patient’s rash has features not seen with this condition; see Discussion for details.

Fungal infection (choice “d”) is also definitely in the differential, but it is unlikely given the negative KOH, the lack of any source for such infection, and the complete lack of response to tolnaftate cream.

DISCUSSION

Impetigo has also been called impetiginized dermatitis because it almost always starts with minor breaks in the skin as a result of conditions such as eczema, acne, contact dermatitis, or insect bite. Thus provided with access to deeper portions of the epithelial surface, bacterial organisms that normally cause no problems on intact skin are able to create a minor but annoying condition we have come to call impetigo.

Mistakenly called infantigo in large parts of the United States, impetigo is quite common but nonetheless alarming. Rarely associated with morbidity, it tends to resolve in two to three weeks at most, even without treatment.

Impetigo has the reputation of being highly contagious; given enough heat and humidity, close living conditions, and lack of regular bathing and/or adequate treatment, it can spread rapidly. Those conditions existed commonly 100 years ago, when bathing was sporadic and often cursory, and multiple family members lived and slept in close quarters. In those days before the introduction of antibiotics, there were no good topical antimicrobial agents, either.

Another factor played a major role in impetigo, bolstering its fearsome reputation. The strains of strep (group A b-hemolytic strep) that caused most impetigo in those days included several so-called nephritogenic strains that could lead to a dreaded complication: acute poststreptococcal glomerulonephritis (APSGN). Also called Bright disease, it could and did lead to fatal renal failure—about which little could be done at the time.

Fortunately, such nephritogenic strains of strep are unusual now, with APSGN occurring at a rate of about 1:1,000,000 in developed countries. In those locations, most people live far different lives today, bathing and changing clothes daily and living in much less cramped quarters.

The patient’s atopy likely had an impact, for several reasons: Since staph colonization of atopic persons is quite common, it’s more likely that an infection will develop. Also, thinner skin that is easily broken, a plethora of complicating problems (eg, dry skin, eczema, contact dermatitis, and exaggerated reactions to insect bites), and a lower threshold for itching all make atopic persons more susceptible to infection.

Most likely, our patient had a touch of eczema or dry skin and scratched it. Then, as the condition progressed, she scratched it more. The peroxide she used would have been highly irritating, serving only to worsen matters.

From a diagnostic point of view, the honey-colored crust covering the lesion and the context in which it developed led to a provisional diagnosis of impetiginized dermatitis. She was treated with oral cephalexin (500 mg tid for 7 d), topical mupirocin (applied bid), and topical hydrocortisone cream 2.5% (daily application). At one week’s follow-up, the patient’s skin was almost totally clear. It’s very unlikely she’ll have any residual scarring or blemish.

Had the diagnosis been unclear, or had the patient not responded to treatment, other diagnoses would have been considered. Among them: discoid lupus, psoriasis, contact dermatitis, and Darier disease.

ANSWER

The correct answer is impetigo (choice “c”), a superficial infection usually caused by a combination of staph and strep organisms.

Psoriasis (choice “a”) would have presented with white, tenacious scaling and would not have been acute in onset.

Eczema (choice “b”) is definitely possible, but the patient’s rash has features not seen with this condition; see Discussion for details.

Fungal infection (choice “d”) is also definitely in the differential, but it is unlikely given the negative KOH, the lack of any source for such infection, and the complete lack of response to tolnaftate cream.

DISCUSSION

Impetigo has also been called impetiginized dermatitis because it almost always starts with minor breaks in the skin as a result of conditions such as eczema, acne, contact dermatitis, or insect bite. Thus provided with access to deeper portions of the epithelial surface, bacterial organisms that normally cause no problems on intact skin are able to create a minor but annoying condition we have come to call impetigo.

Mistakenly called infantigo in large parts of the United States, impetigo is quite common but nonetheless alarming. Rarely associated with morbidity, it tends to resolve in two to three weeks at most, even without treatment.

Impetigo has the reputation of being highly contagious; given enough heat and humidity, close living conditions, and lack of regular bathing and/or adequate treatment, it can spread rapidly. Those conditions existed commonly 100 years ago, when bathing was sporadic and often cursory, and multiple family members lived and slept in close quarters. In those days before the introduction of antibiotics, there were no good topical antimicrobial agents, either.

Another factor played a major role in impetigo, bolstering its fearsome reputation. The strains of strep (group A b-hemolytic strep) that caused most impetigo in those days included several so-called nephritogenic strains that could lead to a dreaded complication: acute poststreptococcal glomerulonephritis (APSGN). Also called Bright disease, it could and did lead to fatal renal failure—about which little could be done at the time.

Fortunately, such nephritogenic strains of strep are unusual now, with APSGN occurring at a rate of about 1:1,000,000 in developed countries. In those locations, most people live far different lives today, bathing and changing clothes daily and living in much less cramped quarters.

The patient’s atopy likely had an impact, for several reasons: Since staph colonization of atopic persons is quite common, it’s more likely that an infection will develop. Also, thinner skin that is easily broken, a plethora of complicating problems (eg, dry skin, eczema, contact dermatitis, and exaggerated reactions to insect bites), and a lower threshold for itching all make atopic persons more susceptible to infection.

Most likely, our patient had a touch of eczema or dry skin and scratched it. Then, as the condition progressed, she scratched it more. The peroxide she used would have been highly irritating, serving only to worsen matters.

From a diagnostic point of view, the honey-colored crust covering the lesion and the context in which it developed led to a provisional diagnosis of impetiginized dermatitis. She was treated with oral cephalexin (500 mg tid for 7 d), topical mupirocin (applied bid), and topical hydrocortisone cream 2.5% (daily application). At one week’s follow-up, the patient’s skin was almost totally clear. It’s very unlikely she’ll have any residual scarring or blemish.

Had the diagnosis been unclear, or had the patient not responded to treatment, other diagnoses would have been considered. Among them: discoid lupus, psoriasis, contact dermatitis, and Darier disease.

ANSWER

The correct answer is impetigo (choice “c”), a superficial infection usually caused by a combination of staph and strep organisms.

Psoriasis (choice “a”) would have presented with white, tenacious scaling and would not have been acute in onset.

Eczema (choice “b”) is definitely possible, but the patient’s rash has features not seen with this condition; see Discussion for details.

Fungal infection (choice “d”) is also definitely in the differential, but it is unlikely given the negative KOH, the lack of any source for such infection, and the complete lack of response to tolnaftate cream.

DISCUSSION

Impetigo has also been called impetiginized dermatitis because it almost always starts with minor breaks in the skin as a result of conditions such as eczema, acne, contact dermatitis, or insect bite. Thus provided with access to deeper portions of the epithelial surface, bacterial organisms that normally cause no problems on intact skin are able to create a minor but annoying condition we have come to call impetigo.

Mistakenly called infantigo in large parts of the United States, impetigo is quite common but nonetheless alarming. Rarely associated with morbidity, it tends to resolve in two to three weeks at most, even without treatment.

Impetigo has the reputation of being highly contagious; given enough heat and humidity, close living conditions, and lack of regular bathing and/or adequate treatment, it can spread rapidly. Those conditions existed commonly 100 years ago, when bathing was sporadic and often cursory, and multiple family members lived and slept in close quarters. In those days before the introduction of antibiotics, there were no good topical antimicrobial agents, either.

Another factor played a major role in impetigo, bolstering its fearsome reputation. The strains of strep (group A b-hemolytic strep) that caused most impetigo in those days included several so-called nephritogenic strains that could lead to a dreaded complication: acute poststreptococcal glomerulonephritis (APSGN). Also called Bright disease, it could and did lead to fatal renal failure—about which little could be done at the time.

Fortunately, such nephritogenic strains of strep are unusual now, with APSGN occurring at a rate of about 1:1,000,000 in developed countries. In those locations, most people live far different lives today, bathing and changing clothes daily and living in much less cramped quarters.

The patient’s atopy likely had an impact, for several reasons: Since staph colonization of atopic persons is quite common, it’s more likely that an infection will develop. Also, thinner skin that is easily broken, a plethora of complicating problems (eg, dry skin, eczema, contact dermatitis, and exaggerated reactions to insect bites), and a lower threshold for itching all make atopic persons more susceptible to infection.

Most likely, our patient had a touch of eczema or dry skin and scratched it. Then, as the condition progressed, she scratched it more. The peroxide she used would have been highly irritating, serving only to worsen matters.

From a diagnostic point of view, the honey-colored crust covering the lesion and the context in which it developed led to a provisional diagnosis of impetiginized dermatitis. She was treated with oral cephalexin (500 mg tid for 7 d), topical mupirocin (applied bid), and topical hydrocortisone cream 2.5% (daily application). At one week’s follow-up, the patient’s skin was almost totally clear. It’s very unlikely she’ll have any residual scarring or blemish.

Had the diagnosis been unclear, or had the patient not responded to treatment, other diagnoses would have been considered. Among them: discoid lupus, psoriasis, contact dermatitis, and Darier disease.

Clinical question: Is there a difference between repositioning intervals of two, three, or four hours in pressure ulcer formation in nursing home residents on high-density foam mattresses?

Background: Pressure ulcer formation in nursing home residents is a common problem. Current standard of care requires repositioning every two hours in patients who are at risk for pressure ulcer formation. Few studies have been performed to assess a difference in repositioning interval. This study was conducted to see if there is a difference in pressure ulcer formation among residents on high-density foam mattresses at moderate to high risk (according to the Braden scale).

Study design: Multi-site, randomized, clinical trial.

Setting: Twenty U.S. and seven Canadian nursing homes using high-density foam mattresses.

Synopsis: A multi-site, randomized clinical trial was executed in 20 U.S. and seven Canadian nursing homes. More than 900 residents were randomized to two-, three-, or four-hour intervals for repositioning. All participants were at either moderate (13-14) or high (10-12) risk on the Braden scale for pressure ulcer formation. All facilities used high-density foam mattresses. All participants were monitored for pressure ulcer formation on the sacrum/coccyx, heel, or trochanter for three consecutive weeks.

There was no significant difference in pressure ulcer formation between the two-, three-, or four-hour interval repositioning groups. There was no significant difference in pressure ulcer formation between the moderate or high-risk groups. Only 2% of participants developed a pressure ulcer, all stage I or II.

It is not clear if the outcomes were purely related to the repositioning intervals, as this study group had a much lower rate of pressure ulcer formation compared to national averages and previous studies. The high-density foam mattress might have improved outcomes by evenly redistributing pressure so that less frequent repositioning was required. The level of documentation may have led to earlier recognition of early stage pressure ulcers as well. This study also was limited to nursing home residents at moderate to high risk of pressure ulcer development.

Bottom line: There is no significant difference in pressure ulcer formation between repositioning intervals of two, three, or four hours among moderate and high-risk nursing home residents using high-density foam mattresses.

Citation: Bergstrom N, Horn SD, Rapp MP, Stern A, Barrett R, Watkiss M. Turning for ulcer reduction: a multisite randomized clinical trial in nursing homes. 2013;61(10):1705-1713.

Clinical question: Is there a difference between repositioning intervals of two, three, or four hours in pressure ulcer formation in nursing home residents on high-density foam mattresses?

Background: Pressure ulcer formation in nursing home residents is a common problem. Current standard of care requires repositioning every two hours in patients who are at risk for pressure ulcer formation. Few studies have been performed to assess a difference in repositioning interval. This study was conducted to see if there is a difference in pressure ulcer formation among residents on high-density foam mattresses at moderate to high risk (according to the Braden scale).

Study design: Multi-site, randomized, clinical trial.

Setting: Twenty U.S. and seven Canadian nursing homes using high-density foam mattresses.

Synopsis: A multi-site, randomized clinical trial was executed in 20 U.S. and seven Canadian nursing homes. More than 900 residents were randomized to two-, three-, or four-hour intervals for repositioning. All participants were at either moderate (13-14) or high (10-12) risk on the Braden scale for pressure ulcer formation. All facilities used high-density foam mattresses. All participants were monitored for pressure ulcer formation on the sacrum/coccyx, heel, or trochanter for three consecutive weeks.

There was no significant difference in pressure ulcer formation between the two-, three-, or four-hour interval repositioning groups. There was no significant difference in pressure ulcer formation between the moderate or high-risk groups. Only 2% of participants developed a pressure ulcer, all stage I or II.

It is not clear if the outcomes were purely related to the repositioning intervals, as this study group had a much lower rate of pressure ulcer formation compared to national averages and previous studies. The high-density foam mattress might have improved outcomes by evenly redistributing pressure so that less frequent repositioning was required. The level of documentation may have led to earlier recognition of early stage pressure ulcers as well. This study also was limited to nursing home residents at moderate to high risk of pressure ulcer development.

Bottom line: There is no significant difference in pressure ulcer formation between repositioning intervals of two, three, or four hours among moderate and high-risk nursing home residents using high-density foam mattresses.

Citation: Bergstrom N, Horn SD, Rapp MP, Stern A, Barrett R, Watkiss M. Turning for ulcer reduction: a multisite randomized clinical trial in nursing homes. 2013;61(10):1705-1713.

Clinical question: Is there a difference between repositioning intervals of two, three, or four hours in pressure ulcer formation in nursing home residents on high-density foam mattresses?

Background: Pressure ulcer formation in nursing home residents is a common problem. Current standard of care requires repositioning every two hours in patients who are at risk for pressure ulcer formation. Few studies have been performed to assess a difference in repositioning interval. This study was conducted to see if there is a difference in pressure ulcer formation among residents on high-density foam mattresses at moderate to high risk (according to the Braden scale).

Study design: Multi-site, randomized, clinical trial.

Setting: Twenty U.S. and seven Canadian nursing homes using high-density foam mattresses.

Synopsis: A multi-site, randomized clinical trial was executed in 20 U.S. and seven Canadian nursing homes. More than 900 residents were randomized to two-, three-, or four-hour intervals for repositioning. All participants were at either moderate (13-14) or high (10-12) risk on the Braden scale for pressure ulcer formation. All facilities used high-density foam mattresses. All participants were monitored for pressure ulcer formation on the sacrum/coccyx, heel, or trochanter for three consecutive weeks.

There was no significant difference in pressure ulcer formation between the two-, three-, or four-hour interval repositioning groups. There was no significant difference in pressure ulcer formation between the moderate or high-risk groups. Only 2% of participants developed a pressure ulcer, all stage I or II.

It is not clear if the outcomes were purely related to the repositioning intervals, as this study group had a much lower rate of pressure ulcer formation compared to national averages and previous studies. The high-density foam mattress might have improved outcomes by evenly redistributing pressure so that less frequent repositioning was required. The level of documentation may have led to earlier recognition of early stage pressure ulcers as well. This study also was limited to nursing home residents at moderate to high risk of pressure ulcer development.

Bottom line: There is no significant difference in pressure ulcer formation between repositioning intervals of two, three, or four hours among moderate and high-risk nursing home residents using high-density foam mattresses.

Citation: Bergstrom N, Horn SD, Rapp MP, Stern A, Barrett R, Watkiss M. Turning for ulcer reduction: a multisite randomized clinical trial in nursing homes. 2013;61(10):1705-1713.

Clinical question: What antibiotic-resistant bacteria are the greatest threats for the next 10 years?

Background: Two million people suffer antibiotic-resistant infections yearly, and 23,000 die each year as a result. Most of these infections occur in the community, but deaths usually occur in healthcare settings. Cost estimates vary but may be as high as $20 billion in excess direct healthcare costs.

Study design: The CDC used several different surveys and databanks, including the National Antimicrobial Resistance Monitoring System, to collect data. The threat level for antibiotic-resistant bacteria was determined using several factors: clinical impact, economic impact, incidence, 10-year projection of incidence, transmissibility, availability of effective antibiotics, and barriers to prevention.

Setting: United States.

Synopsis: The CDC has three classifications of antibiotic-resistant bacteria: urgent, serious, and concerning. Urgent threats are high-consequence, antibiotic-resistant threats because of significant risks identified across several criteria. These threats might not currently be widespread but have the potential to become so and require urgent public health attention to identify infections and to limit transmission. They include carbapenem-resistant Enterobacteriaceae, drug-resistant Neisseria gonorrhoeae, and Clostridium difficile (does not have true resistance, but is a consequence of antibiotic overuse).

Serious threats are significant antibiotic-resistant threats. These threats will worsen and might become urgent without ongoing public health monitoring and prevention activities. They include multidrug-resistant Acinetobacter, drug-resistant Campylobacter, fluconazole-resistant Candida (a fungus), extended-spectrum β-lactamase-producing Enterobacteriaceae, vancomycin-resistant Enterococcus, multidrug-resistant Pseudomonas aeruginosa, drug-resistant non-typhoidal Salmonella, drug-resistant Salmonella Typhimurium, drug-resistant Shigella, methicillin-resistant Staphylococcus aureus, drug-resistant Streptococcus pneumonia, and drug-resistant tuberculosis.

Concerning threats are bacteria for which the threat of antibiotic resistance is low, and/ or there are multiple therapeutic options for resistant infections. These bacterial pathogens cause severe illness. Threats in this category require monitoring and, in some cases, rapid incident or outbreak response. These include vancomycin-resistant Staphylococcus aureus, erythromycin-resistant Group A Streptococcus, and clindamycin-resistant Group B Streptococcus. Research has shown patients with resistant infections have significantly longer hospital stays, delayed recuperation, long-term disability, and higher mortality. As resistance to current antibiotics occurs, providers are forced to use antibiotics that are more toxic, more expensive, and less effective.

The CDC recommends four core actions to fight antibiotic resistance:

• Preventing infections from occurring and preventing resistant bacteria from spreading (immunization, infection control, screening, treatment, and education);
• Tracking resistant bacteria;
• Improving the use of antibiotics (antibiotic stewardship); and
• Promoting the development of new antibiotics and new diagnostic tests for resistant bacteria.

Bottom line: Antibiotics are a limited resource. The more antibiotics are used today, the less likely they will continue to be effective in the future. The CDC lists 18 antibiotic-resistant organisms as urgent, serious, or concerning and recommends actions to combat the spread of current organisms and emergence of new antibiotic organisms.

Citation: Centers for Disease Control and Prevention. Antibiotic resistance threats in the United States, 2013. CDC website. September 16, 2013. Available at: www.cdc.gov/drugresistance/threat-report-2013. Accessed Nov. 30, 2013.

Clinical question: What antibiotic-resistant bacteria are the greatest threats for the next 10 years?

Background: Two million people suffer antibiotic-resistant infections yearly, and 23,000 die each year as a result. Most of these infections occur in the community, but deaths usually occur in healthcare settings. Cost estimates vary but may be as high as $20 billion in excess direct healthcare costs.

Study design: The CDC used several different surveys and databanks, including the National Antimicrobial Resistance Monitoring System, to collect data. The threat level for antibiotic-resistant bacteria was determined using several factors: clinical impact, economic impact, incidence, 10-year projection of incidence, transmissibility, availability of effective antibiotics, and barriers to prevention.

Setting: United States.

Synopsis: The CDC has three classifications of antibiotic-resistant bacteria: urgent, serious, and concerning. Urgent threats are high-consequence, antibiotic-resistant threats because of significant risks identified across several criteria. These threats might not currently be widespread but have the potential to become so and require urgent public health attention to identify infections and to limit transmission. They include carbapenem-resistant Enterobacteriaceae, drug-resistant Neisseria gonorrhoeae, and Clostridium difficile (does not have true resistance, but is a consequence of antibiotic overuse).

Serious threats are significant antibiotic-resistant threats. These threats will worsen and might become urgent without ongoing public health monitoring and prevention activities. They include multidrug-resistant Acinetobacter, drug-resistant Campylobacter, fluconazole-resistant Candida (a fungus), extended-spectrum β-lactamase-producing Enterobacteriaceae, vancomycin-resistant Enterococcus, multidrug-resistant Pseudomonas aeruginosa, drug-resistant non-typhoidal Salmonella, drug-resistant Salmonella Typhimurium, drug-resistant Shigella, methicillin-resistant Staphylococcus aureus, drug-resistant Streptococcus pneumonia, and drug-resistant tuberculosis.

Concerning threats are bacteria for which the threat of antibiotic resistance is low, and/ or there are multiple therapeutic options for resistant infections. These bacterial pathogens cause severe illness. Threats in this category require monitoring and, in some cases, rapid incident or outbreak response. These include vancomycin-resistant Staphylococcus aureus, erythromycin-resistant Group A Streptococcus, and clindamycin-resistant Group B Streptococcus. Research has shown patients with resistant infections have significantly longer hospital stays, delayed recuperation, long-term disability, and higher mortality. As resistance to current antibiotics occurs, providers are forced to use antibiotics that are more toxic, more expensive, and less effective.

The CDC recommends four core actions to fight antibiotic resistance:

• Preventing infections from occurring and preventing resistant bacteria from spreading (immunization, infection control, screening, treatment, and education);
• Tracking resistant bacteria;
• Improving the use of antibiotics (antibiotic stewardship); and
• Promoting the development of new antibiotics and new diagnostic tests for resistant bacteria.

Bottom line: Antibiotics are a limited resource. The more antibiotics are used today, the less likely they will continue to be effective in the future. The CDC lists 18 antibiotic-resistant organisms as urgent, serious, or concerning and recommends actions to combat the spread of current organisms and emergence of new antibiotic organisms.

Citation: Centers for Disease Control and Prevention. Antibiotic resistance threats in the United States, 2013. CDC website. September 16, 2013. Available at: www.cdc.gov/drugresistance/threat-report-2013. Accessed Nov. 30, 2013.

Clinical question: What antibiotic-resistant bacteria are the greatest threats for the next 10 years?

Background: Two million people suffer antibiotic-resistant infections yearly, and 23,000 die each year as a result. Most of these infections occur in the community, but deaths usually occur in healthcare settings. Cost estimates vary but may be as high as $20 billion in excess direct healthcare costs.

Study design: The CDC used several different surveys and databanks, including the National Antimicrobial Resistance Monitoring System, to collect data. The threat level for antibiotic-resistant bacteria was determined using several factors: clinical impact, economic impact, incidence, 10-year projection of incidence, transmissibility, availability of effective antibiotics, and barriers to prevention.

Setting: United States.

Synopsis: The CDC has three classifications of antibiotic-resistant bacteria: urgent, serious, and concerning. Urgent threats are high-consequence, antibiotic-resistant threats because of significant risks identified across several criteria. These threats might not currently be widespread but have the potential to become so and require urgent public health attention to identify infections and to limit transmission. They include carbapenem-resistant Enterobacteriaceae, drug-resistant Neisseria gonorrhoeae, and Clostridium difficile (does not have true resistance, but is a consequence of antibiotic overuse).

Serious threats are significant antibiotic-resistant threats. These threats will worsen and might become urgent without ongoing public health monitoring and prevention activities. They include multidrug-resistant Acinetobacter, drug-resistant Campylobacter, fluconazole-resistant Candida (a fungus), extended-spectrum β-lactamase-producing Enterobacteriaceae, vancomycin-resistant Enterococcus, multidrug-resistant Pseudomonas aeruginosa, drug-resistant non-typhoidal Salmonella, drug-resistant Salmonella Typhimurium, drug-resistant Shigella, methicillin-resistant Staphylococcus aureus, drug-resistant Streptococcus pneumonia, and drug-resistant tuberculosis.

Concerning threats are bacteria for which the threat of antibiotic resistance is low, and/ or there are multiple therapeutic options for resistant infections. These bacterial pathogens cause severe illness. Threats in this category require monitoring and, in some cases, rapid incident or outbreak response. These include vancomycin-resistant Staphylococcus aureus, erythromycin-resistant Group A Streptococcus, and clindamycin-resistant Group B Streptococcus. Research has shown patients with resistant infections have significantly longer hospital stays, delayed recuperation, long-term disability, and higher mortality. As resistance to current antibiotics occurs, providers are forced to use antibiotics that are more toxic, more expensive, and less effective.

The CDC recommends four core actions to fight antibiotic resistance:

• Preventing infections from occurring and preventing resistant bacteria from spreading (immunization, infection control, screening, treatment, and education);
• Tracking resistant bacteria;
• Improving the use of antibiotics (antibiotic stewardship); and
• Promoting the development of new antibiotics and new diagnostic tests for resistant bacteria.

Bottom line: Antibiotics are a limited resource. The more antibiotics are used today, the less likely they will continue to be effective in the future. The CDC lists 18 antibiotic-resistant organisms as urgent, serious, or concerning and recommends actions to combat the spread of current organisms and emergence of new antibiotic organisms.

Citation: Centers for Disease Control and Prevention. Antibiotic resistance threats in the United States, 2013. CDC website. September 16, 2013. Available at: www.cdc.gov/drugresistance/threat-report-2013. Accessed Nov. 30, 2013.

Epidemiology

The several studies of lower extremity injuries sustained while skiing and snowboarding have differed markedly with respect to patient demographics. Kim and colleagues¹ compared snowboarding and skiing injuries over 18 seasons at a Vermont ski resort and found that the injury rate, assessed as mean number of days between injuries, was 400 for snowboarders and 345 for skiers. However, most snowboarding injuries were wrist injuries and generally of the upper extremity, whereas skiing injuries were mainly lower extremity injuries. Overall, young and inexperienced snowboarders had the highest injury rate. In a study on skiing and snowboarding injuries through 4 Utah seasons, Wasden and colleagues² found that mean age at injury was 41 years for skiers and 23 years for snowboarders. This corroborates the finding from several studies^1-3 that snowboarders tend to be younger. Snowboarding is a newer sport with many beginners. However, Ishimaru and colleagues⁴ found that lower extremity injuries may be associated with experienced snowboarders, who may be prone to take more risks and tackle more challenging slopes. Experienced snowboarders are also likely to sustain lower extremity injuries from falling, because of their risk-taking behavior.⁵

Although upper extremity injuries account for most snowboarding injuries, lower extremity injuries are a significant issue.⁶ Modern equipment and more challenging slopes have allowed snowboarders to attain great speeds going down slopes—leading to a surge in lower extremity injuries.⁷ Lower extremity injuries sustained during snowboarding are more likely to be on the leading side⁴; the ankle is the most frequent fracture site. Unlike snowboard equipment, modern ski equipment, including new boots and binding systems, is designed to reduce ankle injuries and lower leg fractures.⁶ The decline in foot, ankle, and tibia fractures can be attributed to taller and stiffer boots, which offer the lower extremities more protection.⁸

Mechanism of Injury

Talus Fractures

An increasingly common injury among snowboarders is a fracture of the lateral process of the talus; this injury accounts for 32% of snowboarders’ ankle fractures.⁶ The lateral process of the talus—wedge-shaped and covered in articular cartilage—is involved in the subtalar and ankle joints.⁹ A fracture here is often misdiagnosed as an ankle sprain (Figures 1–3).^6,9,10 The exact mechanism of injury remains controversial, and several biomechanical factors seem to be involved. Funk and colleagues¹¹ conducted a cadaveric study and concluded that eversion of an axially loaded, dorsiflexed ankle may be the primary injury mechanism for fracture. Furthermore, snowboarders have their feet in a position perpendicular to the board, and a fall parallel to the board could increase the eversion force on the ankle of the leading leg. Valderrabano and colleagues⁹ conducted a clinical study of 26 patients who sustained this injury from snowboarding. All the patients reported they had felt an axial impact from falling, jumping, or unexpectedly hitting a ground object, and 80% reported a rotational movement in the lower leg during the impact. The authors concluded that axial loading and dorsiflexion were not the only factors involved in lateral process talus fractures, and an external moment is necessary to cause this injury from a forward fall.⁹

Anterior Cruciate Ligament Injuries

Although snowboarders’ lower extremity injuries are primarily ankle injuries, snowboarders are also at risk for serious knee issues when landing from jumps. In skiers, anterior cruciate ligament (ACL) injuries have 5 well-established mechanisms, all involving separation of the feet and a twisting force in the knee (Figures 4, 5): boot-induced anterior drawer mechanism, phantom-foot mechanism, valgus-external rotation, forceful quadriceps muscle contraction, and a combination of internal rotation and extension.^8,12 A valgus–external rotation mechanism of knee injury occurs when external rotation of the tibia results from the skier catching the inside edge of the front of the ski. A valgus force acts on the knee as the lower leg is abducted during forward momentum. The torque created on the knee joint is amplified by the length of the knee and commonly results in an ACL injury or medial collateral ligament injury.⁶ Reports indicate that the phantom-foot mechanism is the most common mechanism of ACL injury among skiers.^6,13,14 In this situation, internal rotation of the knee results when an off-balance skier falls backward, which causes the knee to hyperflex. The skier catches an inside edge on the snow, which creates a torque that rotates the tibia relative to the femur and results in injury to the ACL.^6,14 A boot-induced anterior drawer mechanism occurs during a landing, when the tail of the ski lands first and in an off-balance position, resulting in a load transmitted through the skis to the skier; this load causes an anterior drawer of the ski boot and tibia relative to the femur, straining the ACL and causing ACL rupture.^6,13,14 In the forceful quadriceps muscle contraction mechanism of ACL injury, a forceful quadriceps contraction occurs after a jump to prevent a backward fall. With the knee in flexion, this quadriceps contraction causes an anterior translation of the tibia, resulting in ACL rupture.^13,14

The mechanism of injury differs in snowboarding, in which both feet remain attached to the board. Davies and colleagues¹⁵ examined 35 snowboarders who sustained ACL injuries after a flat landing from a jump and concluded that snowboarders preparing for a landing exhibit more quadriceps contraction, which increases the loading force on the ACL during landing. Furthermore, the snowboarder’s stance on the board, with the front foot slightly rotated relative to the board, results in a slight internal tibial rotation of the knee and establishes a posture that makes the snowboarder susceptible to injury. However, the lower incidence of knee injuries among snowboarders compared with skiers may be attributable to the fact that there is a limited amount of torque that can be generated on either knee as both feet are fixed to the board.¹⁶

The increased quadriceps force in anticipation of a landing, combined with the internal tibial rotation of the knee caused by the snowboarder’s stance, may be the primary mechanism of ACL rupture in snowboarders.¹⁵

Injury Prevention Strategies

Prevention strategies require an identification of injury risk factors for snowboarders. Hasler and colleagues⁷ conducted a study with 306 patients to identify variables that presented a risk for snowboarders. Low readiness for speed, bad weather, and bad visibility, as well as snow conditions, were found to be significant risk factors.

Skiers’ overall injury rate has decreased over the past 60 years, and this decrease has been attributed in part to improved ski technique and instruction.^17,18 Improperly adjusted ski bindings are the culprit in many equipment-related lower extremity injuries, and beginners are at much higher risk for such injuries. Lessons and comprehensive safety training could reduce this injury rate.^17,19 Several awareness video and training programs focusing on injury prevention have reduced knee sprains in ski patrollers compared with controls by 62% in 1 study; a similar program reduced injury by 30% in nonprofessional skiers.¹⁷ A study of injured snowboarders during a winter in Scotland found that 37% of the patients had no formal instruction or training in correct snowboarding and falling technique.²⁰ Training programs for snowboarders could yield meaningful results in injury prevention and avoidance of risk-taking behavior among snowboarders.

Advances in equipment have also had an impact on the incidence of skiing injuries. Ski bindings protect skiers in 2 ways. First, the binding keeps the boot attached to the ski and prevents unintended release on difficult terrain. Second, the binding releases the boot from the ski during extreme conditions to prevent the skier from experiencing extreme forces or moments that could result in injury. Functional failure in ski bindings has been implicated in increased incidence of knee injuries and ligament rupture. In a study of injuries sustained by recreational alpine skiers in Japan, Urabe and colleagues²¹ found that 96% of those injured stated that the ski bindings had not released at time of incident. The effects of binding adjustment and maintenance among snowboarders have not been fully investigated, and there are no set guidelines for individual snowboarders on appropriate binding level. However, as there is a range of binding adjustment options available, snowboarders may have an optimum level that maximizes both mobility and protection from injury.²²

Soft-shelled boots may also increase injury risk for snowboarders. Such boots allow for a wider range of ankle motion and offer little protection from extreme joint movements. Soft boots are generally preferred among snowboarders because they allow for increased mobility for sharp turns and maneuvers. However, modification of the stiffness of boots that limit ankle and foot joint mobility could reduce the incidence of ankle fractures and sprains among snowboarders.²²

Summary

Snowboarding has become increasingly popular worldwide. It attracts a loyal group of amateur athletes and has developed into a billion-dollar industry with a growing rank of professionals. Although most snowboarding injuries are upper extremity injuries, the foot, ankle, and knee represent commonly injured areas among recreational and experienced snowboarders. Advances in ski equipment have significantly reduced the incidence of ankle injuries, but rising knee ligament injuries continue to pose a challenge. Foot and ankle injuries remain an issue in snowboarders despite advances in equipment and safety. New snowboard designs and boot and binding modifications may hold promise in decreasing the risk for injury in these athletes.

Epidemiology

The several studies of lower extremity injuries sustained while skiing and snowboarding have differed markedly with respect to patient demographics. Kim and colleagues¹ compared snowboarding and skiing injuries over 18 seasons at a Vermont ski resort and found that the injury rate, assessed as mean number of days between injuries, was 400 for snowboarders and 345 for skiers. However, most snowboarding injuries were wrist injuries and generally of the upper extremity, whereas skiing injuries were mainly lower extremity injuries. Overall, young and inexperienced snowboarders had the highest injury rate. In a study on skiing and snowboarding injuries through 4 Utah seasons, Wasden and colleagues² found that mean age at injury was 41 years for skiers and 23 years for snowboarders. This corroborates the finding from several studies^1-3 that snowboarders tend to be younger. Snowboarding is a newer sport with many beginners. However, Ishimaru and colleagues⁴ found that lower extremity injuries may be associated with experienced snowboarders, who may be prone to take more risks and tackle more challenging slopes. Experienced snowboarders are also likely to sustain lower extremity injuries from falling, because of their risk-taking behavior.⁵

Although upper extremity injuries account for most snowboarding injuries, lower extremity injuries are a significant issue.⁶ Modern equipment and more challenging slopes have allowed snowboarders to attain great speeds going down slopes—leading to a surge in lower extremity injuries.⁷ Lower extremity injuries sustained during snowboarding are more likely to be on the leading side⁴; the ankle is the most frequent fracture site. Unlike snowboard equipment, modern ski equipment, including new boots and binding systems, is designed to reduce ankle injuries and lower leg fractures.⁶ The decline in foot, ankle, and tibia fractures can be attributed to taller and stiffer boots, which offer the lower extremities more protection.⁸

Mechanism of Injury

Talus Fractures

An increasingly common injury among snowboarders is a fracture of the lateral process of the talus; this injury accounts for 32% of snowboarders’ ankle fractures.⁶ The lateral process of the talus—wedge-shaped and covered in articular cartilage—is involved in the subtalar and ankle joints.⁹ A fracture here is often misdiagnosed as an ankle sprain (Figures 1–3).^6,9,10 The exact mechanism of injury remains controversial, and several biomechanical factors seem to be involved. Funk and colleagues¹¹ conducted a cadaveric study and concluded that eversion of an axially loaded, dorsiflexed ankle may be the primary injury mechanism for fracture. Furthermore, snowboarders have their feet in a position perpendicular to the board, and a fall parallel to the board could increase the eversion force on the ankle of the leading leg. Valderrabano and colleagues⁹ conducted a clinical study of 26 patients who sustained this injury from snowboarding. All the patients reported they had felt an axial impact from falling, jumping, or unexpectedly hitting a ground object, and 80% reported a rotational movement in the lower leg during the impact. The authors concluded that axial loading and dorsiflexion were not the only factors involved in lateral process talus fractures, and an external moment is necessary to cause this injury from a forward fall.⁹

Anterior Cruciate Ligament Injuries

Although snowboarders’ lower extremity injuries are primarily ankle injuries, snowboarders are also at risk for serious knee issues when landing from jumps. In skiers, anterior cruciate ligament (ACL) injuries have 5 well-established mechanisms, all involving separation of the feet and a twisting force in the knee (Figures 4, 5): boot-induced anterior drawer mechanism, phantom-foot mechanism, valgus-external rotation, forceful quadriceps muscle contraction, and a combination of internal rotation and extension.^8,12 A valgus–external rotation mechanism of knee injury occurs when external rotation of the tibia results from the skier catching the inside edge of the front of the ski. A valgus force acts on the knee as the lower leg is abducted during forward momentum. The torque created on the knee joint is amplified by the length of the knee and commonly results in an ACL injury or medial collateral ligament injury.⁶ Reports indicate that the phantom-foot mechanism is the most common mechanism of ACL injury among skiers.^6,13,14 In this situation, internal rotation of the knee results when an off-balance skier falls backward, which causes the knee to hyperflex. The skier catches an inside edge on the snow, which creates a torque that rotates the tibia relative to the femur and results in injury to the ACL.^6,14 A boot-induced anterior drawer mechanism occurs during a landing, when the tail of the ski lands first and in an off-balance position, resulting in a load transmitted through the skis to the skier; this load causes an anterior drawer of the ski boot and tibia relative to the femur, straining the ACL and causing ACL rupture.^6,13,14 In the forceful quadriceps muscle contraction mechanism of ACL injury, a forceful quadriceps contraction occurs after a jump to prevent a backward fall. With the knee in flexion, this quadriceps contraction causes an anterior translation of the tibia, resulting in ACL rupture.^13,14

The mechanism of injury differs in snowboarding, in which both feet remain attached to the board. Davies and colleagues¹⁵ examined 35 snowboarders who sustained ACL injuries after a flat landing from a jump and concluded that snowboarders preparing for a landing exhibit more quadriceps contraction, which increases the loading force on the ACL during landing. Furthermore, the snowboarder’s stance on the board, with the front foot slightly rotated relative to the board, results in a slight internal tibial rotation of the knee and establishes a posture that makes the snowboarder susceptible to injury. However, the lower incidence of knee injuries among snowboarders compared with skiers may be attributable to the fact that there is a limited amount of torque that can be generated on either knee as both feet are fixed to the board.¹⁶

The increased quadriceps force in anticipation of a landing, combined with the internal tibial rotation of the knee caused by the snowboarder’s stance, may be the primary mechanism of ACL rupture in snowboarders.¹⁵

Injury Prevention Strategies

Prevention strategies require an identification of injury risk factors for snowboarders. Hasler and colleagues⁷ conducted a study with 306 patients to identify variables that presented a risk for snowboarders. Low readiness for speed, bad weather, and bad visibility, as well as snow conditions, were found to be significant risk factors.

Skiers’ overall injury rate has decreased over the past 60 years, and this decrease has been attributed in part to improved ski technique and instruction.^17,18 Improperly adjusted ski bindings are the culprit in many equipment-related lower extremity injuries, and beginners are at much higher risk for such injuries. Lessons and comprehensive safety training could reduce this injury rate.^17,19 Several awareness video and training programs focusing on injury prevention have reduced knee sprains in ski patrollers compared with controls by 62% in 1 study; a similar program reduced injury by 30% in nonprofessional skiers.¹⁷ A study of injured snowboarders during a winter in Scotland found that 37% of the patients had no formal instruction or training in correct snowboarding and falling technique.²⁰ Training programs for snowboarders could yield meaningful results in injury prevention and avoidance of risk-taking behavior among snowboarders.

Advances in equipment have also had an impact on the incidence of skiing injuries. Ski bindings protect skiers in 2 ways. First, the binding keeps the boot attached to the ski and prevents unintended release on difficult terrain. Second, the binding releases the boot from the ski during extreme conditions to prevent the skier from experiencing extreme forces or moments that could result in injury. Functional failure in ski bindings has been implicated in increased incidence of knee injuries and ligament rupture. In a study of injuries sustained by recreational alpine skiers in Japan, Urabe and colleagues²¹ found that 96% of those injured stated that the ski bindings had not released at time of incident. The effects of binding adjustment and maintenance among snowboarders have not been fully investigated, and there are no set guidelines for individual snowboarders on appropriate binding level. However, as there is a range of binding adjustment options available, snowboarders may have an optimum level that maximizes both mobility and protection from injury.²²

Soft-shelled boots may also increase injury risk for snowboarders. Such boots allow for a wider range of ankle motion and offer little protection from extreme joint movements. Soft boots are generally preferred among snowboarders because they allow for increased mobility for sharp turns and maneuvers. However, modification of the stiffness of boots that limit ankle and foot joint mobility could reduce the incidence of ankle fractures and sprains among snowboarders.²²

Summary

Snowboarding has become increasingly popular worldwide. It attracts a loyal group of amateur athletes and has developed into a billion-dollar industry with a growing rank of professionals. Although most snowboarding injuries are upper extremity injuries, the foot, ankle, and knee represent commonly injured areas among recreational and experienced snowboarders. Advances in ski equipment have significantly reduced the incidence of ankle injuries, but rising knee ligament injuries continue to pose a challenge. Foot and ankle injuries remain an issue in snowboarders despite advances in equipment and safety. New snowboard designs and boot and binding modifications may hold promise in decreasing the risk for injury in these athletes.

Epidemiology

The several studies of lower extremity injuries sustained while skiing and snowboarding have differed markedly with respect to patient demographics. Kim and colleagues¹ compared snowboarding and skiing injuries over 18 seasons at a Vermont ski resort and found that the injury rate, assessed as mean number of days between injuries, was 400 for snowboarders and 345 for skiers. However, most snowboarding injuries were wrist injuries and generally of the upper extremity, whereas skiing injuries were mainly lower extremity injuries. Overall, young and inexperienced snowboarders had the highest injury rate. In a study on skiing and snowboarding injuries through 4 Utah seasons, Wasden and colleagues² found that mean age at injury was 41 years for skiers and 23 years for snowboarders. This corroborates the finding from several studies^1-3 that snowboarders tend to be younger. Snowboarding is a newer sport with many beginners. However, Ishimaru and colleagues⁴ found that lower extremity injuries may be associated with experienced snowboarders, who may be prone to take more risks and tackle more challenging slopes. Experienced snowboarders are also likely to sustain lower extremity injuries from falling, because of their risk-taking behavior.⁵

Although upper extremity injuries account for most snowboarding injuries, lower extremity injuries are a significant issue.⁶ Modern equipment and more challenging slopes have allowed snowboarders to attain great speeds going down slopes—leading to a surge in lower extremity injuries.⁷ Lower extremity injuries sustained during snowboarding are more likely to be on the leading side⁴; the ankle is the most frequent fracture site. Unlike snowboard equipment, modern ski equipment, including new boots and binding systems, is designed to reduce ankle injuries and lower leg fractures.⁶ The decline in foot, ankle, and tibia fractures can be attributed to taller and stiffer boots, which offer the lower extremities more protection.⁸

Mechanism of Injury

Talus Fractures

An increasingly common injury among snowboarders is a fracture of the lateral process of the talus; this injury accounts for 32% of snowboarders’ ankle fractures.⁶ The lateral process of the talus—wedge-shaped and covered in articular cartilage—is involved in the subtalar and ankle joints.⁹ A fracture here is often misdiagnosed as an ankle sprain (Figures 1–3).^6,9,10 The exact mechanism of injury remains controversial, and several biomechanical factors seem to be involved. Funk and colleagues¹¹ conducted a cadaveric study and concluded that eversion of an axially loaded, dorsiflexed ankle may be the primary injury mechanism for fracture. Furthermore, snowboarders have their feet in a position perpendicular to the board, and a fall parallel to the board could increase the eversion force on the ankle of the leading leg. Valderrabano and colleagues⁹ conducted a clinical study of 26 patients who sustained this injury from snowboarding. All the patients reported they had felt an axial impact from falling, jumping, or unexpectedly hitting a ground object, and 80% reported a rotational movement in the lower leg during the impact. The authors concluded that axial loading and dorsiflexion were not the only factors involved in lateral process talus fractures, and an external moment is necessary to cause this injury from a forward fall.⁹

Anterior Cruciate Ligament Injuries

Although snowboarders’ lower extremity injuries are primarily ankle injuries, snowboarders are also at risk for serious knee issues when landing from jumps. In skiers, anterior cruciate ligament (ACL) injuries have 5 well-established mechanisms, all involving separation of the feet and a twisting force in the knee (Figures 4, 5): boot-induced anterior drawer mechanism, phantom-foot mechanism, valgus-external rotation, forceful quadriceps muscle contraction, and a combination of internal rotation and extension.^8,12 A valgus–external rotation mechanism of knee injury occurs when external rotation of the tibia results from the skier catching the inside edge of the front of the ski. A valgus force acts on the knee as the lower leg is abducted during forward momentum. The torque created on the knee joint is amplified by the length of the knee and commonly results in an ACL injury or medial collateral ligament injury.⁶ Reports indicate that the phantom-foot mechanism is the most common mechanism of ACL injury among skiers.^6,13,14 In this situation, internal rotation of the knee results when an off-balance skier falls backward, which causes the knee to hyperflex. The skier catches an inside edge on the snow, which creates a torque that rotates the tibia relative to the femur and results in injury to the ACL.^6,14 A boot-induced anterior drawer mechanism occurs during a landing, when the tail of the ski lands first and in an off-balance position, resulting in a load transmitted through the skis to the skier; this load causes an anterior drawer of the ski boot and tibia relative to the femur, straining the ACL and causing ACL rupture.^6,13,14 In the forceful quadriceps muscle contraction mechanism of ACL injury, a forceful quadriceps contraction occurs after a jump to prevent a backward fall. With the knee in flexion, this quadriceps contraction causes an anterior translation of the tibia, resulting in ACL rupture.^13,14

The mechanism of injury differs in snowboarding, in which both feet remain attached to the board. Davies and colleagues¹⁵ examined 35 snowboarders who sustained ACL injuries after a flat landing from a jump and concluded that snowboarders preparing for a landing exhibit more quadriceps contraction, which increases the loading force on the ACL during landing. Furthermore, the snowboarder’s stance on the board, with the front foot slightly rotated relative to the board, results in a slight internal tibial rotation of the knee and establishes a posture that makes the snowboarder susceptible to injury. However, the lower incidence of knee injuries among snowboarders compared with skiers may be attributable to the fact that there is a limited amount of torque that can be generated on either knee as both feet are fixed to the board.¹⁶

The increased quadriceps force in anticipation of a landing, combined with the internal tibial rotation of the knee caused by the snowboarder’s stance, may be the primary mechanism of ACL rupture in snowboarders.¹⁵

Injury Prevention Strategies

Prevention strategies require an identification of injury risk factors for snowboarders. Hasler and colleagues⁷ conducted a study with 306 patients to identify variables that presented a risk for snowboarders. Low readiness for speed, bad weather, and bad visibility, as well as snow conditions, were found to be significant risk factors.

Skiers’ overall injury rate has decreased over the past 60 years, and this decrease has been attributed in part to improved ski technique and instruction.^17,18 Improperly adjusted ski bindings are the culprit in many equipment-related lower extremity injuries, and beginners are at much higher risk for such injuries. Lessons and comprehensive safety training could reduce this injury rate.^17,19 Several awareness video and training programs focusing on injury prevention have reduced knee sprains in ski patrollers compared with controls by 62% in 1 study; a similar program reduced injury by 30% in nonprofessional skiers.¹⁷ A study of injured snowboarders during a winter in Scotland found that 37% of the patients had no formal instruction or training in correct snowboarding and falling technique.²⁰ Training programs for snowboarders could yield meaningful results in injury prevention and avoidance of risk-taking behavior among snowboarders.

Advances in equipment have also had an impact on the incidence of skiing injuries. Ski bindings protect skiers in 2 ways. First, the binding keeps the boot attached to the ski and prevents unintended release on difficult terrain. Second, the binding releases the boot from the ski during extreme conditions to prevent the skier from experiencing extreme forces or moments that could result in injury. Functional failure in ski bindings has been implicated in increased incidence of knee injuries and ligament rupture. In a study of injuries sustained by recreational alpine skiers in Japan, Urabe and colleagues²¹ found that 96% of those injured stated that the ski bindings had not released at time of incident. The effects of binding adjustment and maintenance among snowboarders have not been fully investigated, and there are no set guidelines for individual snowboarders on appropriate binding level. However, as there is a range of binding adjustment options available, snowboarders may have an optimum level that maximizes both mobility and protection from injury.²²

Soft-shelled boots may also increase injury risk for snowboarders. Such boots allow for a wider range of ankle motion and offer little protection from extreme joint movements. Soft boots are generally preferred among snowboarders because they allow for increased mobility for sharp turns and maneuvers. However, modification of the stiffness of boots that limit ankle and foot joint mobility could reduce the incidence of ankle fractures and sprains among snowboarders.²²

Summary

Snowboarding has become increasingly popular worldwide. It attracts a loyal group of amateur athletes and has developed into a billion-dollar industry with a growing rank of professionals. Although most snowboarding injuries are upper extremity injuries, the foot, ankle, and knee represent commonly injured areas among recreational and experienced snowboarders. Advances in ski equipment have significantly reduced the incidence of ankle injuries, but rising knee ligament injuries continue to pose a challenge. Foot and ankle injuries remain an issue in snowboarders despite advances in equipment and safety. New snowboard designs and boot and binding modifications may hold promise in decreasing the risk for injury in these athletes.