Internal fixation of unstable pelvic ring injuries

Patient-related outcome of unstable pelvic ring fractures stabilized with a minimal invasive screw-rod system

Background

Clinical and radiological outcomes of operatively treated unstable pelvic ring fractures are well documented, whereas little is known about the patient’s related outcome. The purpose of this study is to evaluate the patient-reported outcome after minimal invasive treatment of pelvic ring fractures using the SF-36 and EQ-5D medical outcome scores.

Methods

Patients with unstable pelvic ring fractures treated in our trauma department with a minimal invasive screw-rod system between 01/2004 and 12/2014 were included. Next to patient data (sex, age), injury related details (fracture type, additional injuries, Injury Severity Score (ISS)) as well as operation details (method, time to operation, general complications, adverse events associated with the surgical procedure, revision surgery, fracture reduction) were assessed. The patient related outcome was evaluated using the SF-36 and the EQ-5D score.

Results

A total of 105 patients (57 men; 48 women; mean age 56 ± 21 years) were identified as candidates for the study. 60 patients completed the SF-36 and EQ-5D score after a mean follow-up of five years (60.5 months (14-142 months)). Of these patients 77% were multiply injured with a mean ISS of 26 ± 19. Within the respondent group 22% showed type B and 78% type C pelvic ring fractures. In 82% the dorsal pelvic ring fracture was stabilized using a minimally invasive transiliac internal fixator, in 18% an iliolumbar fixation was performed respectively. The mean physical component score of the SF-36 was 37.9 ± 12.0, the mean mental component score was 49.8 ± 12.5. The mean EQ-5D VAS reached 70.5 ± 24.4.

Conclusion

Patients being multiply injured and treated with minimal invasive treated dorsal pelvic ring fractures were suffering more especially concerning physical domains compared to the healthy reference population. Nevertheless, the overall patient-related outcome is comparable to pelvic ring fractures in general.

Trial Registration Number

Clinical Trial Registry University of Regensburg Z-2017-0878-3. Registered 22. July 2017. Retrospectively registered.

Study of the X-Ray Diagnosis of Unstable Pelvic Fracture Displacements in Three-Dimensional Space and its Application in Closed Reduction

ABSTRACTS Objective: To study the method of X-ray diagnosis of unstable pelvic fractures displaced in three-dimensional (3D) space and its clinical application in closed reduction.

METHODS

Five models of hemipelvic displacement were made in an adult pelvic specimen. Anteroposterior radiographs of the pelvis were analyzed in PACS. The method of X-ray diagnosis was applied in closed reductions. From February 2012 to June 2016, 23 patients (15 men, 8 women; mean age, 43.4 years) with unstable pelvic fractures were included. All patients were treated by closed reduction and percutaneous cannulate screw fixation of the pelvic ring. According to Tile's classification, the patients were classified into type B1 in 7 cases, B2 in 3, B3 in 3, C1 in 5, C2 in 3, and C3 in 2. The operation time and intraoperative blood loss were recorded. Postoperative images were evaluated by Matta radiographic standards.

RESULTS

Five models of displacement were made successfully. The X-ray features of the models were analyzed. For clinical patients, the average operation time was 44.8 min (range, 20-90 min) and the average intraoperative blood loss was 35.7 (range, 20-100) mL. According to the Matta standards, 7 cases were excellent, 12 cases were good, and 4 were fair.

CONCLUSIONS

The displacements in 3D space of unstable pelvic fractures can be diagnosed rapidly by X-ray analysis to guide closed reduction, with a satisfactory clinical outcome.

Comparisons of front plate, percutaneous sacroiliac screws, and sacroiliac anterior papilionaceous plate in fixation of unstable pelvic fractures

BACKGROUND

This observational study was aimed at comparing the clinical efficacy of sacroiliac anterior plate fixation (SAPF), sacroiliac anterior papilionaceous plate (SAPP), and percutaneous sacroiliac screw internal fixation (PSCIF) introduced for patients with unstable pelvic fracture.

METHODS

Seventy-eight patients with unstable pelvic fracture (Tile type B or C) were recruited. Twenty-six patients underwent SAPF, 26 underwent SAPP, and 26 underwent PSCIF. Matta scores were calculated to evaluate the reduction of pelvic fractures, and Majeed scores were applied for the assessment of functional recoveries after surgery. Other perioperative clinical indicators were also recorded, including operation time, bleeding status, length of incision, ambulation time, fracture healing time, and incision infection.

RESULTS

Total operation time of PSCIF was remarkably shorter than that of SAPF and SAPP (P < .05), and the bleeding volume of SAPF and SAPP group was almost 26∼29 times as high as that of PSCIF group (P < .05). Besides, SAPP resulted in significant blood loss compared with SAPF (P < .05), while SAPF resulted in significantly larger operative incision length than SAPP and PSCIF (P < .05). Moreover, patients' stay time was prolonged in both SAPF and SAPP groups than in the PSCIF group (P < .05). Patients who received PSCIF exhibited significantly higher Matta and Majeed scores than those who received SAPF (all P < .05). Finally, SAPP was associated with fewer complications than SAPF, and complications were barely observed in the PSCIF group.

CONCLUSION

PSCIF may be more appropriate for patients with unstable pelvic fractures in comparison with SAPP and SAPF. Besides, SAPP is likely to be more efficacious than SAPF especially for Tile C patients.

A computed tomographic anatomical study of the upper sacrum. Application for a user guide of pelvic fixation with iliosacral screws in adult spinal deformity

PURPOSE

Widely used in traumatic pelvic ring fractures, the iliosacral (IS) screw technique for spino-pelvic fixation remains anecdotal in adult spinal deformity. The objective of this study was to assess anatomical variability of the adult upper sacrum and to provide a user guide of spino-pelvic fixation with IS screws in adult spinal deformity.

METHODS

Anatomical variability of the upper sacrum according to age, gender, height and weight was sought on 30 consecutive pelvic CT-scans. Thus, a user guide of spino-pelvic fixation with IS screws was modeled and assessed on ten CT-scans as described below. Two invariable landmarks usable during the surgical procedure were defined: point A (corresponding to the connector binding the IS screw to the spinal rod), equidistant from the first posterior sacral hole and the base of the S1 articular facet and 10 mm-embedded into the sacrum; point B (corresponding to the tip of the IS screw) located at the junction of the anterior third and middle third of the sacral endplate in the sagittal plane and at the middle of the endplate in the coronal plane. Point C corresponded to the intersection between the A-B direction and the external facet of the iliac wing. Three-dimensional reconstructions modeling the IS screw optimal direction according to the A-B-C straight line were assessed.

RESULTS

Age had no effect on the anatomy of the upper sacrum. The distance between the base of the S1 superior articular facet and the top of the first posterior sacral hole was correlated with weight (r = 0.6; 95% CI [0.6-0.9]); p < 0.001). Sacral end-plate thickness increased for male patients (p < 0.001) and was strongly correlated with height (r = 0.6; 95% CI [0.29-0.75]); p < 0.001) and weight (r = 0.8; 95% CI [0.6-0.9]); p < 0.001). The thickness of the inferior part of the S1 vertebral body increased in male patients (p < 0.001). Other measured parameters slightly varied according to gender, height and weight. Simulating the described technique of pelvic fixation, no misplaced IS screw was found whatever the age, gender and morphologic parameters.

CONCLUSION

This user guide of spinopelvic fixation with IS screws seems to be reliable and reproducible independently of age, gender and morphologic characteristics but needs clinical assessment.

LEVEL OF EVIDENCE

Level IV.

Percutaneous iliosacral screw fixation in unstable pelvic fractures

Surgical treatment of unstable pelvic fractures Type C, has a vertical instability that is not controlled by traction and supine; therefore, orthopedic and functional treatments undertaken by default are sources of complications. The closed reduction with percutaneous sacroiliac fixation solves the problem of vertical instability; but at the cost of learning the method. Five patients with unstable pelvic fractures; were treated by percutaneous sacroiliac fixation. This reliable and useful method in the stabilization of unstable pelvic fractures. Good functional results are predictable based on the severity of pelvic fractures and associated injuries. The low rates of complications and the minimally invasive nature are the advantages of this method.

Late reconstruction of severe open-book deformities of the pelvis - tips and tricks

BACKGROUND

The primary goal of treatment for open book pelvic injuries after high-energy trauma is to control haemorrhage and to close the pelvic ring anatomically. Less commonly, patients may present late with malunion or non-union.

METHODS

We reviewed five operatively treated patients with delayed severe open book deformities who had a diastasis of more than 6 cm. We describe the pre-operative workup, surgical strategy and challenges experienced. They specifically include: extensive scar and contracture formation, malunion, urogenital prolapse and difficult reduction of vertical shear element. A 5 to 15-point clinical scoring system based on quality of life regarding pain, ambulation, social function, continence control and presence of prolapse is proposed.

RESULTS

One elderly patient had early mortality after surgery. The other four patients had quality of life improvement by 3 to 5 points after one year. Correction is often clinically successful despite technical challenges and unpredictable radiological results.

CONCLUSION

External fixator and the C-clamp are good reduction tools. Powerful implants should be used and fixation of the posterior ring is mandatory. Staged urogenital and pelvic floor reconstruction is recommended before bony reconstruction to minimize the risk of wound contamination. Patients receiving this complex procedure have a good chance for improvement in pain and functional status.

Minimally invasive plate osteosynthesis on anterior pelvic ring injury and anterior column acetabular fracture

INTRODUCTION

In performing surgery for fractures of the pelvis and acetabulum, various surgical approaches have been introduced with their own advantages and drawbacks. The extensile nature of ilioinguinal approach gives excellent exposure but was related to wound healing problems. Modified stoppa has a higher difficulty and poses a risk for neurovascular injury. In this study, we elaborate our experience using the Modified Stoppa approach with additional lateral window while adding few modifications to simplify the procedure and facilitate future implant removal.

METHODS

A prospective-retrospective cohort involving 30 anterior pelvic ring and/or anterior column acetabulum fracture patients were conducted from 2012-2016. Fifteen cases were prospectively treated using the modified approach since 2014, while the remaining fifteen cases that were treated using Ilioinguinal approach were retrospectively reviewed. Intraoperative parameters such as blood loss, duration of surgery, quality of reduction (Matta) and postoperative functional outcome (Majeed and Hannover score) at 12 months period were recorded and evaluated by a blinded reviewer.

RESULT

There were no significant differences between the two groups in mean age, sex and fracture type. The mean blood loss in the MIPO group were 325 ± 225 mL versus 710.67 ± 384.51 mL in the control group (p = 0.002). Duration of surgery were 149.33 ± 91.92 minutes in MIPO group versus 235.71 ± 65.79 minutes in ilioinguinal group (p = 0.014). There were no significant differences noted between the two groups in the quality of reduction and postoperative functional outcome, either by using Majeed or Hannover pelvic score. No complications were found after a 12-months follow up period. Two modified cases already had their implant removed and during the procedure, fibrotic tissue were minimal making the implant removal was less complicated and easier.

CONCLUSIONS

Modified stoppa and lateral window technique can be used as a safe and effective alternative approach for anterior pelvic ring fracture and/or anterior column acetabulum fracture. This approach decreased the duration of surgery and blood loss without compromising the quality of reduction and functional outcome in patients.

The use of external fixators in the definitive stabilisation of the pelvis in polytrauma patients: Safety, efficacy and clinical outcomes

OBJECTIVES

To analyse the complications and outcomes (functional/radiographic) of Pelvic External Fixators applied as part of the definitive fixation in polytrauma patients.

DESIGN

A single center retrospective chart review.

SETTING

A level-1 trauma center.

PATIENTS AND METHODS

We reviewed all the polytrauma patients (ISS>16) between 2007 and 2012 that had a PEF applied more than 30days. Complications including infection, aseptic loosening, neurological injury, loss of reduction, non-union and mal-union were recorded. Pelvic asymmetry and Deformity Index (DI) were measured at the immediate postoperative radiographs and final follow-up. The functional outcome at final follow up was estimated using a scale previously reported by Chiou et al.

RESULTS

59 patients with mean age of 38.4 (16 - 81) years and mean ISS score 28 (16- 66) were included. The PEFs were applied for mean duration of 56 (30-104) days. The average follow-up was 403days. 22 injuries were type B and 37 type C (AO/OTA). The most common symptomatic complications were pin site infection in 11 (18.6%) and loosening in 5 (8.5%) cases. 44 (74.5%) patients had satisfactory functional outcome. The immediate post-operative and final asymmetry and DI were compared between the two pelvic injury groups (type B and C fractures). The difference in displacement progression was more for type C injuries (p=0.034) but no correlation to the functional outcome was evident.

CONCLUSION

PEF can be used as definitive alternative stabilization method in specific situations at polytrauma setting. Radiological displacement occurred in both type B and C injuries but the clinical outcome was not correlated to this displacement. Complications related to PEF do not affect the final clinical outcome.

LEVEL OF EVIDENCE

Therapeutic Level III.

Early Postoperative Displacement of Combined Pelvic Ring Injury With Acetabular Fracture

Combined pelvic ring and acetabular injuries present a management challenge. The literature on this topic is scarce, with few outcomes studies available. This retrospective study assessed whether the incidence of postoperative displacement and loss of reduction is higher with combined injuries compared with isolated pelvic ring injuries and isolated acetabular fractures. The charts and radiographs of 33 patients with combined pelvic ring and acetabular fractures treated operatively during a 7-year period at a single institution were reviewed. Pelvic ring and acetabular displacements were measured during the early postoperative period and compared with final follow-up measurements (minimum 5 months after surgery). Measurements also were compared with those from isolated pelvic ring fractures (n=33) and isolated acetabular fractures (n=33). Groups were matched for injury pattern and were propensity-matched by age and Injury Severity Score. Patients with combined injuries and patients with isolated pelvic ring injuries had similar initial pelvic ring reductions on anteroposterior and outlet view radiographs. By final follow-up, the combined injury group had experienced significant additional pelvic ring displacement. The presence of combined injury was an independent risk factor for postoperative pelvic ring displacement. Initial postoperative acetabular displacement was higher in the combined injury group compared with the isolated acetabular fracture group (2.6±1.8 vs 1.1±1.1 mm). By final followup, apparent displacement decreased significantly for both groups. Patients with combined pelvic ring and acetabular fractures were more likely to have poorer acetabular reduction and additional displacement of the pelvic ring component during the postoperative period compared with patients with isolated injuries. [Orthopedics. 2017; 40(3):163-168.].

Percutaneous screws CT guided to fix sacroiliac joint in tile C pelvic injury. Outcomes at 5 years of follow-up

INTRODUCTION

The treatment of the sacroiliac joint (SIJ) vertical instability is a matter of current discussions and remains controversial. The aim of our study is the evaluation of the surgical management of SIJ vertical instability involving the use of cannulated screws introduced under CT guidance and local anesthesia.

MATERIALS AND METHODS

In the set time frame of 7 years, 96 poly-trauma patients with Tile's type C fracture of the pelvis with vertical instability of the SIJ were treated. The average distance between the two stumps was 73.4 mm (range: 43-100 mm). All patients were treated with anterior stabilization and subsequent stabilization with cannulated screws (Asnis® Stryker® 6 mm, an average length of 70 mm; range from 55 to 85 mm) of the sacroiliac fracture. The clinical and radiological follow-up was performed with follow-up plain radiograph and Majeed score (from 1 to 60 months after injury).

RESULTS

The consolidation of pelvic fractures was obtained after an average of 63 days. The average Majeed score was as follows: 96 points at 1 month, 84 points at 3 months, 62 points at 6 months, 44 points at 12 months, 42 points at 24 months, 32 points at 36 months, 28 points at 48 months and 28 points at 60 months. Complications were as follows: not fatal deep vein thrombosis in five cases, skin infection at the entry point of the screws in six cases, screw breakage in one case and loosening of the screws in one case. Radiological evidence of fracture consolidation was achieved on average at 63 days. Forty-seven patients managed to get back to their pre-trauma employment at the end of the convalescence period.

CONCLUSIONS

Our results suggest that the stabilization of SI Tile type C fracture/dislocations with CT-guided percutaneous cannulated screws is a valid and feasible management option and associated with a low complication rate.

PHYSICAL SYMMETRY AND VIRTUAL PLANE-BASED REDUCTION REFERENCE: A PRELIMINARY STUDY FOR ROBOT-ASSISTED PELVIC FRACTURE REDUCTION

Traditional pelvis fracture reduction suffers from some disadvantages. Robot-assisted pelvis fracture reduction offers some promise in solving these problems. However, the reduction reference to guide robot motion is a key issue that must be resolved. In this paper, we propose a physical symmetry and virtual plane-based reduction reference and adopt the method of registration to calculate the virtual plane for the reference, which were verified via experiments. The results of the position symmetry experiments of the original pelvis and virtual plane-based position symmetry experiments were similar; both showed that the symmetry errors of the pelvis were less than 4[Formula: see text]mm and 2.5[Formula: see text]. The results indicated that the proposed method could be used as a reference for robot-assisted pelvis fracture reduction.

Effect of the subcutaneous route for iliac screw insertion in lumbopelvic fixation for vertical unstable sacral fractures on the infection rate: A retrospective case series

OBJECTIVE

To report the perioperative results and surgical outcomes of patients with vertical unstable sacral fractures who underwent lumbopelvic fixation through a modified subcutaneous route for iliac screw fixation.

SUMMARY OF BACKGROUND DATA

Treating vertical unstable sacral fractures is still challenging for orthopedic surgeons. Among various methods for treating these fractures, lumbopelvic fixation provides a high reduction quality and promising stability for early weight-bearing ambulation. However, wound healing disturbance and surgical site infection (SSI) are the drawbacks of this extensive technique, especially after inserting iliac screws.

METHODS

Here, we provide an alternative subcutaneous route for iliac screw insertion during lumbopelvic fixation surgery to lessen soft tissue retraction and injury, and thus decrease soft tissue complications.

RESULTS

Using this modified technique, 28 patients with vertical unstable sacral fractures were treated between 2012 and 2014. One patient had an SSI (infection rate: 3.5%). All fractures were united with a mean sacral kyphosis correction angle of 10.5°. The mean Majeed score of the 17 patients during the 12-month follow-up was 84.5.

CONCLUSIONS

The subcutaneous route for iliac screw insertion is a simple, safe, and effective technique when performing lumbopelvic fixation for vertical unstable sacral fractures.

Internal versus external fixation of the anterior component in unstable fractures of the pelvic ring: pooled results from a systematic review

PURPOSE

Improving reduction of the pelvic ring improves long-term functional outcomes for patients. It has been demonstrated that posterior internal fixation is necessary to adequately control fractures to the posterior ring and there is evidence that supplementing this with fixation of the anterior ring improves stability. It is accepted that internal fixation provides greater stability than external fixation of the anterior ring but long-term differences in radiographic and functional outcomes have not yet been quantified.

METHODS

A search of electronic databases, reference lists and review articles from 1989 to 2015 yielded 18 studies (n = 884) that met our inclusion criteria. We included studies that discussed pelvic ring injuries in adults, reported functional or radiological outcomes or complications by anterior ring intervention and exceeded 14 patients. We excluded biomechanical and cadaver studies.

RESULTS

Internal fixation of the anterior pelvic ring had better functional and radiographic outcomes. Residual displacement of >10 mm was less common with internal fixation (ER 0.12, 95 % CI 0.06-0.24) than external fixation (ER 0.31, 95 % CI 0.11-0.62). Unsatisfactory outcomes also occurred at a lower rate (ER 0.09, 95 % CI 0.03-0.22) compared to external fixation (ER 0.32, 95 % CI 0.18-0.50). Losses of reduction (ER 0.02, 95 % CI 0.01-0.04 versus ER 0.07, 95 % CI 0.02-0.21), malunions (ER 0.03, 95 % CI 0.01-0.08 versus ER 0.07, 95 % CI 0.02-0.21) and delayed/non-unions (ER 0.02, 95 % CI 0.01-0.05 versus ER 0.04, 95 % CI 0.02-0.07).

CONCLUSIONS

Internal fixation of the anterior pelvic ring as supplementary fixation for unstable injuries to the pelvic ring appears to result in better radiographic and functional outcomes as well as fewer complications. However, data that separated outcomes and complications in relation to interventions of the anterior pelvic ring were limited. More studies looking specifically at outcomes in relation to the type of anterior ring intervention are needed.

Modified ilioinguinal approach in combined surgical exposures for displaced acetabular fractures involving two columns

The purpose of this study is to assess the advantages of modified ilioinguinal approach in combined surgical exposures for displaced acetabular fractures involving two columns management. 73 patients with displaced acetabular fractures involving two columns underwent open reduction and internal fixation through combined surgical approaches between 2006 and 2014 in our hospital. The modified ilioinguinal approach combined with Kocher–Langenbeck approach group (group A) included 46 patients. The standard ilioinguinal approach combined with Kocher–Langenbeck approach group (group B) included 27 patients. Outcome was assessed in operative time, blood loss, function outcomes and complications. In group A, the average operative time was 123.2 min, and the average blood loss was 586.2 ml. Anatomic reduction was achieved in 39 patients (84.8 %). The functional recovery was good in 37 patients (80.4 %). Complications related to the approach were observed in 10 patients (21.7 %). In group B, the average operative time was 161.5 min, and the average blood loss was 830 ml. Anatomic reduction was achieved in 24 patients (88.9 %). The functional recovery was good in 22 patients (81.5 %). Complications related to the approach were observed in 9 patients (33.3 %). This study demonstrates that both combined approaches permits good postoperative function results for treatment of acetabular fractures involving two columns. However, the modified ilioinguinal approach combined with Kocher–Langenbeck approach provides less operative time, blood loss and complications.

The Effect of Transiliac-Transsacral Screw Fixation for Pelvic Ring Injuries on the Uninjured Sacroiliac Joint

OBJECTIVE

To evaluate the functional outcomes and pain in patients with unilateral posterior pelvic ring injuries treated with transiliac-transsacral screw fixation compared with unilateral iliosacral screw fixation.

DESIGN

Retrospective comparative study.

SETTING

Three academic level 1 trauma centers.

PATIENTS/PARTICIPANTS

From a group of 866 patients with pelvic ring injuries treated surgically, 86 patients with unilateral pelvic ring injuries treated with transiliac-transsacral screws and 97 patients treated with unilateral iliosacral screws were identified. Thirty-six patients treated with transiliac-transsacral fixation and 26 patients treated with unilateral iliosacral screws met the inclusion criteria and participated.

INTERVENTION

Patients were treated surgically for unstable pelvic ring injuries with either unilateral iliosacral screws or transiliac-transsacral screws at the discretion of the treating surgeon.

MAIN OUTCOME MEASUREMENT

Majeed Pelvic Score.

RESULTS

There was no significant difference in Majeed Pelvic Scores between patients treated with transiliac-transsacral screws and those treated with unilateral iliosacral screws (72.8 ± 23.7 vs. 70.4 ± 19.0, P = 0.66). There was no difference in side-specific Numeric Rating Scale pain scores between patients treated with transiliac-transsacral screws and those treated with unilateral iliosacral screws on the injured side (2.5 ± 3.1 vs. 2.0 ± 2.4, P = 0.46) or the uninjured side (1.7 ± 2.8 vs. 0.8 ± 1.7, P = 0.12). Mean follow-up was greater than 3 years with no difference between the groups (mean 1270 vs. 1242 days, P = 0.84).

CONCLUSIONS

Treatment of unilateral pelvic ring injuries with transiliac-transsacral screws does not adversely affect or improve patient outcomes or subjective pain scores when compared with those treated with unilateral iliosacral screws.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Stoppa Approach for Anterior Plate Fixation in Unstable Pelvic Ring Injury

BACKGROUND

The Stoppa (intrapelvic) approach has been introduced for the treatment of pelvic-acetabular fractures; it allows easy exposure of the pelvic brim, where the bone quality is optimal for screw fixation. The purpose of our study was to investigate the surgical outcomes of unstable pelvic ring injuries treated using the Stoppa approach for stable anterior ring fixation.

METHODS

We analyzed 22 cases of unstable pelvic ring injury treated with plate fixation of the anterior ring with the Stoppa approach. We excluded cases of nondisplaced rami fracture, simple symphyseal diastasis, and parasymphyseal fractures, which can be easily treated with other techniques. The average age of the study patients was 41 years (range, 23 to 61 years). There were 10 males and 12 females. According to the Young and Burgess classification, there were 12 lateral compression, 4 anteroposterior compression, and 6 vertical shear fracture patterns. The fracture location on the anterior ring was near the iliopectineal eminence in all cases and exposure of the pelvic brim was required for plate fixation. All patients were placed in the supine position. For anterior plate fixation, all screws were applied to the anterior ramus distally and directed above the hip joint proximally. Radiologic outcomes were assessed by union time and quality of reduction by Matta method. The Merle d'Aubigne-Postel score was used to evaluate the functional results.

RESULTS

The average radiologic follow-up period was 16 months (range, 10 to 51 months). All fractures united at an average of 3.5 months (range, 3 to 5 months). According to the Matta method, the quality of reduction was classified as follows: 16 anatomical (73%) and 6 nearly anatomical (27%) reductions. There were no cases of screw or implant loosening before bone healing. The functional results were classified as 7 excellent (32%), 12 good (55%), and 3 fair (13%) by the Merle d'Aubigne-Postel score. There were no wound complications, neurovascular injuries, or other complications related to the surgical approach.

CONCLUSIONS

Stable anterior ring fixation placed via the Stoppa approach can result in excellent reduction and stable screw fixation with a low complication rate.

Bowel preparation prior to percutaneous ilio-sacral screw insertion: is it necessary?

PURPOSE

The aim of this study was to compare the outcomes of ilio-sacral (IS) screw fixation with and without the use of bowel preparation, in terms of obtaining adequate visualisation, malpositioning of screw requiring revision surgery and neurovascular injury.

METHODS

A retrospective case control study was performed. We reviewed 74 consecutive cases of IS screw fixation performed at our institution within the last 5 years. We included all patients who had undergone percutaneous IS screw fixation. Two groups, one consisting of patients who underwent bowel preparation prior to surgery (Group 1) and one consisting of patients who had no bowel preparation (Group 2), were compared in terms of the above outcomes. There were 37 patients in each group. The mean age in Group 1 was 41 years (17-63) and in Group 2 was 47 years (12-89).

RESULTS

In Group 1 there were two procedures abandoned due to poor visualisation. In Group 2 there were no cases abandoned for poor visualisation. There were two nerve injuries in Group 1 and no nerve injuries in Group 2. Revision surgery was performed in four patients in Group 1-for malposition, persistent buttock pain, sciatic nerve palsy and inadequate fixation while one revision performed in Group 2 for persistent buttock pain.

CONCLUSION

Based on these results, we conclude that bowel preparation is not necessary to obtain adequate visualisation for safe and accurate percutaneous IS screw insertion. In fact, in Group 1 two procedures were abandoned and there was higher incidence of complications. Therefore, it would appear that this treatment arm should be abandoned all together. Further studies to prove it conclusively and explain the reasons are required.

Do Transsacral-transiliac Screws Across Uninjured Sacroiliac Joints Affect Pain and Functional Outcomes in Trauma Patients?

BACKGROUND

Patients with pelvic ring displacement and instability can benefit from surgical reduction and instrumentation to stabilize the pelvis and improve functional outcomes. Current treatments include iliosacral screw or transsacral-transiliac screw, which provides greater biomechanical stability. However, controversy exists regarding the effects of placement of a screw across an uninjured sacroiliac joint for pelvis stabilization after trauma.

QUESTIONS/PURPOSES

Does transsacral-transiliac screw fixation of an uninjured sacroiliac joint increase pain and worsen functional outcomes at minimum 1-year followup compared with patients undergoing standard iliosacral screw fixation across the injured sacroiliac joint in patients who have sustained pelvic trauma?

METHODS

All patients between ages 18 and 84 years who sustained injuries to the pelvic ring (AO/OTA 61 A, B, C) who were surgically treated between 2011 and 2013 at an academic Level I trauma center were identified for selection. We included patients with unilateral sacroiliac disruption or sacral fractures treated with standard iliosacral screws across an injured hemipelvis and/or transsacral-transiliac screws placed in the posterior ring. Transsacral-transiliac screws were generally more likely to be used in patients with vertically unstable sacral injuries of the posterior ring as a result of previous reports of failures or in osteopenic patients. We excluded patients with bilateral posterior pelvic ring injuries, fixation with a device other than a screw, previous pelvic or acetabular fractures, associated acetabular fractures, and ankylosing spondylitis. Of the 110 patients who met study criteria, 53 (44%) were available for followup at least 12 months postinjury. Sixty patients were unable to be contacted by phone or mail and seven declined to participate in the study. Outcomes were obtained by members of the research team using the visual analog scale (VAS) pain score for both posterior sacroiliac joints, Short Musculoskeletal Functional Assessment (SMFA), and Majeed scores. Patients completed the forms by themselves when able to return to the clinic. A phone interview was performed for others after they received the outcome forms by mail or email.

RESULTS

There were no differences between iliosacral and transsacral-transiliac in terms of VAS injured (2.9 ± 2.9 versus 3.0 ± 2.8, mean difference = 0.1 [95% confidence interval, -1.6 to 1.7], p = 0.91), VAS uninjured (1.8 ± 2.4 versus 2.0 ± 2.6, mean difference = 0.2 [-1.3 to 1.6], p = 0.82), Majeed (80.3 ± 19.9, 79.3 ± 17.5, mean difference = 1.0 [-11.6 to 9.6], p = 0.92), SMFA Function (22.8 ± 22.2, 21.0 ± 17.6, mean difference = 1.8 [-13.2 to 9.6], p = 0.29, and SMFA Bother (24.3 ± 23.8, 29.7 ± 23.4, mean difference = 5.4 [-7.8 to 18.6], p = 0.42).

CONCLUSIONS

Placement of fixation across a contralateral, uninjured sacroiliac joint resulted in no differences in pain and function when compared with standard iliosacral screw placement across an injured hemipelvis at least 1 year after instrumentation. When needed for biomechanical stability, transsacral-transiliac fixation across an uninjured sacroiliac joint can be used without expectation of positive or negative effects on pain or functional outcomes at minimum 1-year followup.

LEVEL OF EVIDENCE

Level III, therapeutic study.

A Quantitative Exposure Planning Tool for Surgical Approaches to the Sacroiliac Joint

OBJECTIVES

To aid in surgical planning by quantifying and comparing the osseous exposure between the anterior and posterior approaches to the sacroiliac joint.

METHODS

Anterior and posterior approaches were performed on 12 sacroiliac joints in 6 fresh-frozen torsos. Visual and palpable access to relevant surgical landmarks was recorded. Calibrated digital photographs were taken of each approach and analyzed using Image J.

RESULTS

The average surface areas of exposed bone were 44 and 33 cm for the anterior and posterior approaches, respectively. The anterior iliolumbar ligament footprint could be visualized in all anterior approaches, whereas the posterior aspect could be visualized in all but one posterior approach. The anterior approach provided visual and palpable access to the anterior superior edge of the sacroiliac joint in all specimens, the posterior superior edge in 75% of specimens, and the inferior margin in 25% and 50% of specimens, respectively. The inferior sacroiliac joint was easily visualized and palpated in all posterior approaches, although access to the anterior and posterior superior edges was more limited. The anterior S1 neuroforamen was not visualized with either approach and was more consistently palpated when going posterior (33% vs. 92%).

CONCLUSIONS

Both anterior and posterior approaches can be used for open reduction of pure sacroiliac dislocations, each with specific areas for assessing reduction. In light of current plate dimensions, fractures more than 2.5 cm lateral to the anterior iliolumbar ligament footprint are amenable to anterior plate fixation, whereas those more medial may be better addressed through a posterior approach.

Biomechanical Comparison of Two Kinds of Internal Fixation in a Type C Zone II Pelvic Fracture Model

BACKGROUND

Unstable pelvic fractures are complex and serious injuries. Selection of a fixation method for these fractures remains a challenging problem for orthopedic surgeons. This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws and minimally invasive adjustable plate (MIAP) combined with one IS screw.

METHODS

This study was a biomechanical experiment. Six embalmed specimens of the adult pelvis were used. The soft tissue was removed from the specimens, and the spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were made on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with two kinds of internal fixation in turn. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500 N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor.

STATISTICAL ANALYSIS USED

Paired-samples t-test.

RESULTS

Under the vertical load of 100, 200, 300, 400, and 500 N, the average displacement of the specimens fixed with MIAP combined with one IS screw was 0.46, 0.735, 1.377, 1.823, and 2.215 mm, respectively, which was significantly lower than that of specimens fixed with two IS screws under corresponding load (P < 0.05). Under the vertical load of 500 N, the shift in the fracture gap of specimens fixed with MIAP combined with one IS screw was 0.261 ± 0.095 mm, and that of specimens fixed with two IS screws was 0.809 ± 0.170 mm. The difference was significant (P < 0.05).

CONCLUSION

The stability of Tile C pelvic fractures fixed with MIAP combined with one IS screw was better than that fixed with two IS screws.

Immediate percutaneous sacroiliac screw insertion for unstable pelvic fractures: is it safe enough?

OBJECTIVES

The purpose of this study was to compare the results of immediate and delayed percutaneous sacroiliac screws surgery for unstable pelvic fractures, regarding technical results and complication rate.

DESIGN

Retrospective study.

SETTING

The study was conducted at the Soroka University Medical center, Beer Sheva, Israel, which is a level 1 trauma Center.

PATIENTS

108 patients with unstable pelvic injuries were operated by the orthopedic department at the Soroka University Medical Center between the years 1999-2010. A retrospective analysis found 50 patients with immediate surgery and 58 patients with delayed surgery. Preoperative and postoperative imaging were analyzed and data was collected regarding complications.

INTERVENTION

All patients were operated on by using the same technique-percutaneous fixation of sacroiliac joint with cannulated screws.

MAIN OUTCOME MEASUREMENTS

The study's primary outcome measure was the safety and quality of the early operation in comparison with the late operation.

RESULTS

A total of 156 sacroiliac screws were inserted. No differences were found between the immediate and delayed treatment groups regarding technical outcome measures (P value = 0.44) and complication rate (P value = 0.42).

CONCLUSIONS

The current study demonstrated that immediate percutaneous sacroiliac screw insertion for unstable pelvic fractures produced equally good technical results, in comparison with the conventional delayed operation, without additional complications.

Primary stability of three different iliosacral screw fixation techniques in osteoporotic cadaver specimens-a biomechanical investigation

BACKGROUND

The incidence of osteoporotic and insufficiency fractures of the pelvic ring is increasing. Closed reduction and percutaneous fixation with cannulated sacroiliac screws is well-established in the operative treatment of osteoporotic posterior pelvic ring fractures. However, osteoporotic bone quality might lead to the risk of screw loosening. For this reason, cement augmentation of the iliosacral screws is more frequently performed and recommended.

PURPOSE

The aim of the present biomechanical study was to evaluate the primary stability of three methods of iliosacral screw fixation in human osteoporotic sacrum specimens.

STUDY DESIGN/SETTING

This study used methodical cadaver study.

METHODS

A total of 15 fresh frozen human cadaveric specimens with osteoporosis were used (os sacrum). After matched pair randomization regarding bone quality (T-score), three operation technique groups were generated: screw fixation (cannulated screws) without cement augmentation (Group A); screw fixation with cement augmentation before screw placement (cannulated screws) (Group B); and screw fixation with perforated screws and cement augmentation after screw placement (Group C). In all specimens both sides of the os sacrum were used for operative treatment, resulting in a group size of 10 specimens per group. One operation technique was used on each side of the sacral bone to compare biomechanical properties in the same bone quality. Pull-out tests were performed with a rate of 6 mm/min. A load versus displacement curve was generated.

RESULTS

Subgroup 1 (Group A vs. Group B): Screw fixation without cement augmentation: 594.4 N±463.7 and screw fixation with cement augmentation before screw placement: 1,020.8 N±333.3; values were significantly different (p=.025). Subgroup 2 (Group A vs. Group C): Screw fixation without cement augmentation: 641.8 N±242.0 and perforated screw fixation with cement augmentation after screw placement: 1,029.6 N±326.5; values were significantly different (p=.048). Subgroup 3 (Group B vs. Group C): Screw fixation with cement augmentation before screw placement: 804.0 N±515.3 and perforated screw fixation with cement augmentation after screw placement: 889.8 N±503.3; values were not significantly different (p=.472).

CONCLUSIONS

Regarding iliosacral screw fixation in osteoporotic bone, the primary stability of techniques involving cement augmentation is significantly higher compared with screw fixation without cement augmentation. Perforated screws with the same primary stability as that of conventional screw fixation in combination with cement augmentation might be a promising alternative in reducing complications of cement leakage. These biomechanical results have to be transferred into clinical practice and prove their clinical value.

A simple approach for the preoperative assessment of sacral morphology for percutaneous SI screw fixation

BACKGROUND

Percutaneous sacroiliac screw fixation under fluoroscopic control is an effective method for posterior pelvic ring stabilization. However, sacral dysmorphism has a high risk of L5 nerve injury. This study describes a simple method for the preoperative assessment of the sacral morphology using CT scans with widely available tools.

MATERIALS AND METHODS

CT scans of 1000 patients were analyzed. True inlet, outlet, and lateral views of the sacrum were obtained using a two-dimensional reconstruction tool to align the sacrum in a reproducible manner. Corridor morphology in the inlet view was measured to calculate different morphological types: (1) Ascending type, (2) Horizontal type, and (3) Descending type. In a second step, the corridor was analyzed for the presence of an anterior indentation of the sacrum between the SI joint and the midsagittal plane with proximity to the nerve root L5, which, therefore, may be harmed during screw misplacement.

RESULTS

A notch was found in the majority of cases with relative frequencies ranging from 69 % (upper quartile of S1) to 95 % (upper quartile of S2). Descending types were, by far, the most frequent corridor type with one exception: In the upper quartile of S1, the ascending type was the most frequent corridor (71 %). Horizontal types were less frequent with a relative incidence between 2 and 14 %.

DISCUSSION

This study should increase the awareness for sacral dysmorphism, emphasize the importance of a preoperative assessment of the osseous corridor, and provide a simple method for the preoperative assessment with widely available tools.

Minimally invasive surgery under fluoro-navigation for anterior pelvic ring fractures

BACKGROUND

The incidence of pelvic fractures in trauma patients is reported to be 3-8.2%, with roughly half of these fractures being caused by high energy injuries with a potential for catastrophic hemorrhage and death. Indications for internal fixation of anterior pelvic ring are controversial. Because of fears of disturbing the pelvic hematoma and causing additional hemorrhage, open reduction and internal fixation of pelvic ring disruption is routinely delayed. In contrast to conventional surgery, percutaneous screw fixation is gaining popularity in the treatment of pelvic and acetabular fractures mainly because of minimal soft tissue damage, less operative blood loss, early surgical intervention and comfortable mobilization of the patient. Fluoro-navigation is a new surgical technique in orthopedic trauma surgery. This study is to investigate clinical results of fluoro-navigation surgery in anterior pelvic ring fractures.

MATERIALS AND METHODS

From January 2006 to October 2011, 23 patients with anterior pelvic ring fractures were treated with percutaneous cannulated screw under fluoro-navigation. There were 14 men and 9 women, with a mean age of 40.1 years (range 25-55). According to the AO and Orthopedic Trauma Association classification, there were seven A 2.1, two A 2.2, one A 2.3, six B 1.2, one B 2.1: 1, one B 2.2, one C 1.2, two C 1.3 and two C 2.3 types of fractures. Amongst these patients, 13 had posterior pelvic ring injuries, 8 had other injuries including urethral, lumbar vertebrae fractures and femoral fractures. All patients were operated when their general condition stabilized after emergency management. The mean time from injury to percutaneous screw fixation of the anterior pelvic ring fracture was 12 days (3-15 days). All the anterior ring fractures were fixed with cannulated screws by two senior surgeons. They were familiar with the navigation system and had gained much experience in the computer-assisted percutaneous placement of screws.

RESULTS

A total of 32 screws were inserted, including 19 in the pubic ramis and 13 in the anterior acetabular columns. The average surgical time was 23.3 min/screw. The average time of X-ray exposure was 19.1 ± 2.5 s/screw. The virtual images of fluoro-navigation were compared with real-time X-rays during and after the surgery. Compared to the final position of the screw, the average deviated distance was 3.11 mm and the average trajectory difference was 2.81°. Blood loss during the operation was minimal (22.3 ml/screw). One screw (3.1%) deviated out of the fracture site during the operation. No superficial or deep infection occurred. No patient sustained recognized neurologic, vascular, or urologic injury as a result of the percutaneous screw fixation. All fractures united at the last followup.

CONCLUSIONS

Fluoro-navigation technique could become a safe, accurate, and fairly quick method for the treatment of anterior pelvic ring fractures. Standardization of the operative procedure and training are mandatory for the success of this procedure.

Computer-aided pelvic reduction frame for anatomical closed reduction of unstable pelvic fractures

Traditional closed reductions of unstable pelvic fractures are mainly performed by surgeons using manual manipulation and subjective verification based on intra-operative roentgenography. It is difficult to perform an accurate closed reduction because of a lack of adequate knowledge of the displacement patterns and an inability to apply the reduction in correct direction. Using the concept of the remote center of motion mechanism and computer-aided design software, we developed a pelvic reduction frame for use in anatomical closed reductions of unstable pelvic fractures. With three-dimensional reconstruction technique and the matrix algorithm, the spatial orientation of the displaced hemipelvis can be calculated and deconstructed into several rotational and translational movements that can be completed with the frame. To verify the accuracy of this system, the rotations were repeated 10 times in arbitrary degrees and directions. After the matrix is calculated, the displaced hemipelvis can be reduced to the anatomical position using our frame. The maximum residual translational and rotational displacements were less than 5 mm and 4 degrees, which indicated the accuracy of this system. The maximum average residual translation and rotation were 1.87 mm in Z-axis (ranging: 4.63-0.1 mm) and 1.1 degrees around Y-axis (ranging: 3.81-0.13 degrees), respectively. Only the Z-axial translation showed a statistically significant difference (p < 0.05). In conclusion, the proposed pelvic reduction frame could be a useful tool for the anatomical reduction of unstable pelvic fractures.

Is Closed Reduction and Percutaneous Fixation of Unstable Posterior Ring Injuries as Accurate as Open Reduction and Internal Fixation?

OBJECTIVES

The objective of this retrospective review was to determine whether a closed reduction technique for unstable pelvic ring injuries is as accurate as an open technique.

DESIGN

Retrospective review.

SETTING

Two academic Level 1 trauma centers.

PATIENTS/PARTICIPANTS

We reviewed the records of 113 patients who had unilateral unstable pelvic ring injuries (Bucholz type 3, OTA type 61-C1) treated with closed reduction and percutaneous fixation (CRPF) or open reduction with internal fixation (ORIF).

INTERVENTION

Sixty patients were treated at one institution with open reduction and percutaneous iliosacral screw fixation. This involved prone positioning and a gluteus maximus sparing approach for direct visualization and reduction of the fracture. A second cohort of 53 patients was treated at a separate institution with closed reduction and percutaneous iliosacral screw fixation. This involved supine positioning and skeletal traction.

MAIN OUTCOME MEASURES

Preoperative and postoperative plain radiographs of the pelvis were reviewed and standardized measurements were made to compare quality of reduction.

RESULTS

We were able to measure displacement within 0.1 mm. Overall reduction quality was slightly better for the CRPF group. The largest average difference in postoperative displacement was seen at the iliac wing height on anteroposterior pelvis radiographs with 6.3 mm (range 0-19.6) in the ORIF group versus 1.9 mm (range 0-4.7) in the CRPF group.

CONCLUSIONS

The closed reduction technique described here is as effective as the ORIF technique in obtaining reduction of unstable pelvic ring injuries (Bucholz type 3, OTA type 61-C1).

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Anatomical considerations for percutaneous trans ilio-sacroiliac S1 and S2 screw placement

OBJECTIVE

To determine the presence of a consistent osseous corridor through S1 and S2 and fluoroscopic landmarks thereof, which could be used for safe trans ilio-sacroiliac screw fixation of posterior pelvic ring disorders.

STUDY DESIGN

Computed tomography (CT) based anatomical investigation utilising multiplanar image and trajectory reconstruction (Agfa-IMPAX Version 5.2 software). Determination of the presence and dimension of a continuous osseous corridor in the coronal plane of the sacrum at the S1 and S2 vertebral levels.

OUTCOME MEASURES

Determination of: (a) the presence of an osseous corridor in the coronal plane through S1 and S2 in males and females; (b) the dimension of the corridor with regard to diameter and length; (c) the fluoroscopic landmarks of the corridor.

RESULTS

The mean cross-sectional area for S1 corridors in males and females was 2.13 and 1.47 cm(2) , respectively. The mean cross-sectional area for the S2 corridor in males and females was 1.46 and 1.13 cm(2), respectively. The limiting anatomical factor is the sagittal diameter of the sacral ala at the junction to the vertebral body. The centre of the S1 and S2 corridor is located in close proximity to the centre of the S1 and S2 vertebrae on the lateral fluoroscopic view as determined by the adjacent endplates and anterior and posterior vertebral cortices.

CONCLUSION

Two-thirds of males and females have a complete osseous corridor to pass a trans-sacroiliac S1 screw of 8 mm diameter. The S2 corridor was present in all males but only in 87 % of females. Preoperative review of the axial CT slices at the midpoint of the S1 or S2 vertebral body allows the presence of a trans-sacroiliac osseous corridor to be determined by assessing the passage at the narrowest point of the corridor at the junction of the sacral ala to the vertebral body.

Percutaneous Screw Fixation of Crescent Fracture-Dislocation of the Sacroiliac Joint

Crescent fracture-dislocation of the sacroiliac joint (CFDSIJ) is a type of lateral compression pelvic injury associated with instability. Open reduction and internal fixation is a traditional treatment of CFDSIJ. However, a minimally invasive method has never been reported. The purpose of this study was to assess the outcome of closed reduction and percutaneous fixation for different types of CFDSIJ and present their clinical outcome. The authors reviewed 117 patients diagnosed with CFDSIJ between July 2003 and July 2013. Closed reduction and percutaneous fixation was performed in 73 patients. Treatment selection was based on Day's fracture classification. For type I fractures, fixation perpendicular to the fracture line were performed. For type II fractures, crossed fixation was performed. For type III fractures, fixation was performed with iliosacral screws. Forty-four patients were treated by open reduction and plate fixation. Demographics, fracture pattern distribution, blood loss, incision lengths, revision surgeries, radiological results, and functional scores were compared. All 117 patients were followed for more than 6 months (mean, 14 months [range, 6-24 months]). Blood loss, extensive exposure, duration of posterior ring surgery, duration of hospital stay, and infection rates were lower in the closed group (P<.01). Patients in the closed group achieved better functional performance (P<.01). There were no significant differences in reduction quality (P=.32), revision surgery rates (P=.27), and iatrogenic neurologic injuries (P=.2) between the 2 groups. The authors' results indicate that closed reduction and percutaneous fixation is a safe and effective surgical method for CFDSIJ.

Does Removal of the Symphyseal Cartilage in Symphyseal Dislocations Have Any Effect on Final Alignment and Implant Failure?

OBJECTIVES

To compare final symphyseal alignment, incidence of implant failure, and revision surgery with and without symphyseal cartilage excision in patients with symphyseal dislocations treated operatively.

DESIGN

Retrospective review.

SETTING

Two academic level 1 trauma centers.

PATIENTS/PARTICIPANTS

We reviewed the records of 96 patients (89 men, 7 women) who had anterior posterior compression (APC) type 2 and 3 injuries requiring anterior plating. The average age was 46 years, and the average Injury Severity Score was 15.6.

INTERVENTION

Fifty patients were treated with symphyseal cartilage removal, whereas a second cohort of 46 patients was treated without removal of the symphyseal cartilage at the time of symphyseal open reduction and internal fixation during the same time period in a different center. Operative indications were the same for both centers, with iliosacral screws used only for type 3 injuries. Both centers used 6-hole plates through a rectus sparing approach.

MAIN OUTCOME MEASUREMENTS

Symphyseal separation was measured radiographically on preoperative and postoperative anteroposterior (AP) and outlet projections. The incidence of implant failure was recorded from the final postoperative radiograph available. Revision surgery was documented.

RESULTS

The symphyseal space after cartilage excision was less than if retained, which was maintained through union. The incidence of implant failure was statistically lower when symphyseal cartilage was excised. There were 2 revisions of symphyseal fixation in the symphyseal retention group for implant failure versus none when excised.

CONCLUSIONS

Symphyseal cartilage excision led to closer apposition of the symphyseal bodies, which correlated with substantially lower rates of implant failure, and revision surgery.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A computer aided measurement method for unstable pelvic fractures based on standardized radiographs

BACKGROUND

To set up a method for measuring radiographic displacement of unstable pelvic ring fractures based on standardized X-ray images and then test its reliability and validity using a software-based measurement technique.

METHODS

Twenty-five patients that were diagnosed as AO/OTA type B or C pelvic fractures with unilateral pelvis fractured and dislocated were eligible for inclusion by a review of medical records in our clinical centre. Based on the input pelvic preoperative CT data, the standardized X-ray images, including inlet, outlet, and anterior-posterior (AP) radiographs, were simulated using Armira software (Visage Imaging GmbH, Berlin, Germany). After representative anatomic landmarks were marked on the standardized X-ray images, the 2-dimensional (2D) coordinates of these points could be revealed in Digimizer software (Model: Mitutoyo Corp., Tokyo, Japan). Subsequently, we developed a formula that indicated the translational and rotational displacement patterns of the injured hemipelvis. Five separate observers calculated the displacement outcomes using the established formula and determined the rotational patterns using a 3D-CT model based on their overall impression. We performed 3D reconstruction of all the fractured pelvises using Mimics (Materialise, Haasrode, Belgium) and determined the translational and rotational displacement using 3-matic suite. The interobserver reliability of the new method was assessed by comparing the continuous measure and categorical outcomes using intraclass correlation coefficient (ICC) and kappa statistic, respectively.

RESULT

The interobserver reliability of the new method for translational and rotational measurement was high, with both ICCs above 0.9. Rotational outcome assessed by the new method was the same as that concluded by 3-matic software. The agreement for rotational outcome among orthopaedic surgeons based on overall impression was poor (kappa statistic, 0.250 to 0.426). Compared with the 3D reconstruction outcome, the interobserver reliability of the formula method for translational and rotational measures was perfect with both ICCs more than 0.9.

CONCLUSIONS

The new method for measuring displacement using a formula was reliable, and could minimise the measurement errors and maximise the precision of pelvic fracture description. Furthermore, this study was useful for standardising the operative plan and establishing a theoretical basis for robot-assisted pelvic fracture surgery based on 2-D radiographs.

Isolated sacral injuries: Postoperative length of stay, complications, and readmission

AIM: To investigate inpatient length of stay (LOS), complication rates, and readmission rates for sacral fracture patients based on operative approach.

METHODS: All patients who presented to a large tertiary care center with isolated sacral fractures in an 11-year period were included in a retrospective chart review. Operative approach (open reduction internal fixation vs percutaneous) was noted, as well as age, gender, race, and American Society of Anesthesiologists’ score. Complications included infection, nonunion and malunion, deep venous thrombosis, and hardware problems; 90-d readmissions were broken down into infection, surgical revision of the sacral fracture, and medical complications. LOS was collected for the initial admission and readmission visits if applicable. Fisher’s exact and non-parametric t-tests (Mann-Whitney U tests) were employed to compare LOS, complications, and readmissions between open and percutaneous approaches.

RESULTS: Ninety-four patients with isolated sacral fractures were identified: 31 (30.4%) who underwent open reduction and internal fixation (ORIF) vs 63 (67.0%) who underwent percutaneous fixation. There was a significant difference in LOS based on operative approach: 9.1 d for ORIF patients vs 6.1 d for percutaneous patients (P = 0.043), amounting to a difference in cost of $13590. Ten patients in the study developed complications, with no significant difference in complication rates or reasons for complications between the two groups (19.4% for ORIF patients vs 6.3% for percutaneous patients). Eight patients were readmitted, with no significant difference in readmission rates or reasons for readmission between the two groups (9.5% percutaneous vs 6.5% ORIF).

CONCLUSION: There is a significant difference in LOS based on operative approach for sacral fracture patients. Given similar complications and readmission rates, we recommend a percutaneous approach.

Modified Ilioinguinal Approach to Treat Pelvic or Acetabular Fractures: A Retrospective Study

The aim of this study was to evaluate the potential advantages and clinical results of a modified minimally invasive ilioinguinal approach for the treatment of acetabular or pelvic fractures to the results obtained using a standard ilioinguinal approach. Forty-six patients who were diagnosed as having anterior column acetabular fractures or anterior pelvic ring fractures underwent open reduction and internal fixation through 2 different surgical approaches between June 2008 to June 2012 in our trauma center was studied. The modified ilioinguinal group included 20 patients and the other 26 patients were in the standard ilioinguinal approach group. The clinical and radiographic results were recorded and compared between the 2 groups. There were no significant differences between 2 groups in the mean age, sex, fractures type, and causes of acetabular or pelvic fractures. The mean blood loss in the modified group was 560.0 ± 57.3 mL versus 850.0 ± 59.0 mL in the standard ilioinguinal group. The operative time was significantly reduced with modified ilioinguinal approach (86.0 ± 4.56 min vs. 101.9 ± 5.38 min). The mean hospital stay was 16.8 ± 0.58 days and 18.7 ± 0.52 days in the modified and standard ilioinguinal groups, respectively. According to the Matta score, the quality of reduction between the 2 groups was not significantly different. The complication rate was low in the modified group but not significantly different between the 2 groups. Forty-two patients were followed up with clinical examination and radiographs at a mean of 15.2 months. Solid union was observed in 42 cases at a mean time of 14.8 weeks. The mean Harris Hip Score and the Majeed scores at the time of evaluation were not significantly different between the 2 groups. On comparing the 2 surgical ilioinguinal approaches, it was found that using modified ilioinguinal approach decreased operative time and blood loss, and did not affect the quality of fracture reduction and fracture healing. This study demonstrates that the modified ilioinguinal approach is a simple and minimally invasive approach for anterior column acetabular fractures and pubic rami fractures comparing with the standard ilioinguinal approach.

A biomechanical study of standard posterior pelvic ring fixation versus a posterior pedicle screw construct

OBJECTIVES

The purpose of this study was to biomechanically test a percutaneous pedicle screw construct for posterior pelvic stabilisation and compare it to standard fixation modalities.

METHODS

Utilizing a sacral fracture and sacroiliac (SI) joint disruption model, we tested 4 constructs in single-leg stance: an S1 sacroiliac screw, S1 and S2 screws, the pedicle screw construct, and the pedicle screw construct+S1 screw. We recorded displacement at the pubic symphysis and SI joint using high-speed video. Axial stiffness was also calculated. Values were compared using a 2-way ANOVA with Bonferroni adjustment (p<0.05).

RESULTS

In the sacral fracture model, the stiffness was greatest for the pedicle screw+S1 construct (p<0.001). There was no significant difference between the pedicle screw construct and S1 sacroiliac screw (p=1). For the SI joint model, the S1+S2 SI screws had the largest overall load and stiffness (p<0.001). The S1 screw was significantly stronger than pedicle screw construct (p=0.001).

CONCLUSIONS

The pedicle screw construct biomechanically compares to currently accepted methods of fixation for sacral fractures when the fracture is uncompressible. It should not be used for SI joint disruptions as one SI or an S1+S2 are significantly stiffer and cheaper.

Radiographic diagnosis of sagittal plane rotational displacement in pelvic fractures: a cadaveric model and clinical case study

PURPOSES

Our objective was to measure the sagittal plane rotational (flexion and extension) displacement of hemipelvis radiologically and analyze the ratio of flexion and extension displacement of unstable pelvic fractures.

METHODS

We used 8 cadaveric models to study the radiographic evidence of pelvic fractures in the sagittal plane. We performed pelvic osteotomy on 8 cadavers to simulate anterior and posterior pelvic ring injury. Radiological data were measured in the flexion and extension group under different angles (5°, 10°, 15°, 20°, and 25°). We retrospectively reviewed 164 patients who were diagnosed with a unilateral fracture of the pelvis. Pelvic ring displacement was identified and recorded radiographically in cadaveric models.

RESULTS

The flexion and extension displacement of pelvic fractures was measured in terms of the vertical distance of fracture from the top of iliac crest to the pubic tubercle (CD) or from the top of iliac crest to the lowest point of ischial tuberosity (AB). Fifty-seven pelves showed flexion displacement and 15 showed extension displacement. Closed reduction including internal fixation and external fixation was successfully used in 141 cases (86.0 %). The success rates of closed reduction in flexion and extension displacement groups were 77 and 73 %, respectively, which were lower than in unstable pelvic ring fractures.

CONCLUSIONS

The sagittal plane rotation (flexion and extension) displacement of pelvic fractures could be measured by special points and lines on the radiographs. Minimally invasive reduction should be based on clearly identified differences between the sagittal plane rotation and the vertical displacement of pelvic fractures.

Percutaneous iliosacral screw fixation after osteoporotic posterior ring fractures of the pelvis reduces pain significantly in elderly patients

INTRODUCTION

Osteoporotic posterior ring fractures of the pelvis are common injuries in the elderly, but the treatment of these fractures still remains controversial. Percutaneous iliosacral screw fixation is one surgical option if conservative treatment cannot provide sufficient pain reduction. The aim of this study is to provide short-term results of elderly patients with percutaneous screw fixation.

METHODS

30 patients with posterior ring fractures were treated between 12/2009 and 01/2014 with percutaneous iliosacral screw fixation. Patients' mean age was 78.4 years. Concerning short-term outcome, we focused on initial pain level and postoperative pain reduction together with intra- and postoperative complications.

RESULTS

The average hospital stay was 23.7 days, with surgical treatment performed after an average of 9.2 days. 90% of our patients were female. All 30 patients had a lower level of pain at discharge compared with admission or immediately prior to surgery. The difference in pain level at admission compared with the pain level upon discharge showed a mean reduction from 6.8 to 1.8 with a statistically significant change (P≤0.001). 24 of 30 patients had no registered complications, one screw malpositioning with postoperative nerve irritation occurred.

DISCUSSION

Conventional percutaneous iliosacral screw fixation is a successful operative treatment for elderly patients with persistent lower back pain after unstable posterior ring fractures of the pelvis. Intra- and postoperative complications are rare, so this treatment can be regarded as a safe procedure.

LEVEL OF EVIDENCE

IV (retrospective study).

Supplemental S1 fixation for type C pelvic ring injuries: biomechanical study of a long iliosacral versus a transsacral screw

Background

A single iliosacral screw placed into the S1 vertebral body has been shown to be clinically unreliable for certain type C pelvic ring injuries. Insertion of a second supplemental iliosacral screw into the S1 or S2 vertebral body has been widely used. However, clinical fixation failures have been reported using this technique, and a supplemental long iliosacral or transsacral screw has been used. The purpose of this study was to compare the biomechanical effect of a supplemental S1 long iliosacral screw versus a transsacral screw in an unstable type C vertically oriented sacral fracture model.

Materials and methods

A type C pelvic ring injury was created in ten osteopenic/osteoporotic cadaver pelves by performing vertical osteotomies through zone 2 of the sacrum and the ipsilateral pubic rami. The sacrum was reduced maintaining a 2-mm fracture gap to simulate a closed-reduction model. All specimens were fixed using one 7.0-mm iliosacral screw into the S1 body. A supplemental long iliosacral screw was placed into the S1 body in five specimens. A supplemental transsacral S1 screw was placed in the other five. Each pelvis underwent 100,000 cycles at 250 N, followed by loading to failure. Vertical displacements at 25,000, 50,000, 75,000, and 100,000 cycles and failure force were recorded.

Results

Vertical displacement increased significantly (p < 0.05) within each group with each increase in the number of cycles. However, there was no statistically significant difference between groups in displacement or load to failure.

Conclusions

Although intuitively a transsacral screw may seem to be better than a long iliosacral screw in conveying additional stability to an unstable sacral fracture fixation construct, we were not able to identify any biomechanical advantage of one method over the other.

Level of evidence

Does not apply—biomechanical study.

Investigation of bone quality of the first and second sacral segments amongst trauma patients: concerns about iliosacral screw fixation

Background

Iliosacral screw fixation has become a common method for surgical stabilization of acute disruptions of the pelvic ring. Placement of iliosacral screws into the first sacral (S1) body is the preferred method of fixation, but size limitations and sacral dysmorphism may preclude S1 fixation. In these clinical situations, fixation into the second sacral (S2) body has been recommended. The objective of this study was to evaluate the bone quality of the S1 compared to S2 in the described “safe zone” of iliosacral screw fixation in trauma patients.

Materials and methods

The pelvic computed tomography scans of 25 consecutive trauma patients, ages 18–49, at a level 1 trauma center were prospectively analyzed. Hounsfield units, a standardized computed tomography attenuation coefficient, was utilized to measure regional cancellous bone mineral density of the S1 and S2. No change in the clinical protocol or treatment occurred as a consequence of inclusion in this study.

Results

A statically significant difference in bone quality was found when comparing the first and second sacral segment (p = 0.0001). Age, gender, or smoking status did not independently affect bone quality.

Conclusion

In relatively young, otherwise healthy trauma patients there is a statistically significant difference in the bone density of the first sacral segment compared to the second sacral segment. This study highlights the need for future biomechanical studies to investigate whether this difference is clinically relevant. Due to the relative osteopenia in the second sacral segment, which may impact the quality of fixation, we feel this technique should be used with caution.

Level of evidence

III

Do asymptomatic patients have normal function after percutaneous fixation of the posterior pelvic ring? A case-control pilot study

Background

Following treatment of a posterior pelvic disruption, residual deformity or associated injuries can adversely affect functional recovery. No study has been performed on gait and functional outcome after closed reduction and percutaneous screw fixation (CRPSF) of posterior pelvic disruption in clinically asymptomatic patients. The purpose of this study was to determine if gait and functional outcome are different from normal in asymptomatic patients with a posterior pelvic injury after CRPSF, serving as a pilot study in this regard.

Methods

Six asymptomatic patients with no grossly evident gait abnormality, treated by CRPSF for a posterior pelvic disruption, were included in the study (SG). A control group (CG) of six healthy volunteers was created. All participants completed the 12-Item Short Form Health Survey version 2 (SF-12v2), the Majeed Pelvic Score (MPS), and the Iowa Pelvic Score (IPS). In addition, the participants’ gait was analyzed.

Results

Pelvic drop was significantly smaller on the uninjured side in the SG when compared to the injured side in the SG. There was no significant difference between the injured and uninjured side for other gait parameters within the SG. Knee angle at initial contact was significantly greater on the injured side when compared to the CG. The SG scored statistically worse than the CG on the Physical Component Summary part of the SF-12v2. However, when evaluated by age group using national mean scores, the SG differences were minimal. All six patients in our study scored “excellent” on both MPS and IPS.

Conclusions

Despite having subclinical alterations in gait, asymptomatic pelvic ring injured patients show minimal, if any, evidence of impaired functional outcome following successful reduction of a posterior pelvic disruption treated by CRPSF.

Vertical pelvic ring displacement in pelvic ring injury: Measurements in pelvic outlet radiograph and in cadavers

BACKGROUND

Vertical pelvic ring displacement (VPRD) is a serious injury and needs assessment. Pelvic outlet radiographs are routinely taken. However, relationship of radiographic and actual VPRD is still in question. Thus, measurement of VPRD from pelvic radiographs was studied.

MATERIALS AND METHODS

2 dry pelvic bones and 1 sacrum from same cadaver was reconstructed to be the pelvic ring. Five specimens were enrolled. 10, 20 and 30 mm vertical displacement of right pelvic bone was performed at levels of sacroiliac joint and pubic symphysis for representing right VPRD. Then, the pelvis was set sacral inclination at 60° from X-ray table for outlet and anteroposterior pelvic radiographs. Right VPRD was measured by referring to superior most pelvic articular surface of both sacroiliac joints and sacral long axis. Radiographic VPRD and actual displacement were analyzed by Pearson correlation coefficient at more than 0.90 for the strong correlation and strongly significant simple regression analysis was set at P < 0.01.

RESULTS

Radiographic VPRD from outlet and anteroposterior pelvic views at 10 mm actual displacement were 20.12 ± 1.98 and 4.08 ± 3.76 mm, at 20 mm were 40.31 ± 1.97 and 9.94 ± 7.27 mm and at 30 mm were 58.56 ± 2.53 and 11.29 ± 2.89 mm. Statistical analyses showed that radiographic VPRD from pelvic outlet view is 1.95 times of actual displacement with strong correlation at 0.992 coefficient and strongly significant regression analysis (P < 0.001) with 0.984 of R (2) value. Whereas, the measurement from anteroposterior pelvic radiograph was not strongly significant.

CONCLUSION

Pelvic outlet radiograph provides efficient measurement of VPRD with 2 times of actual displacement.

Nonoperative treatment of intermediate severity lateral compression type 1 pelvic ring injuries with minimally displaced complete sacral fracture

OBJECTIVES

Controversy exists regarding optimum management of lateral compression type 1 (LC1) pelvic ring injuries (OTA type 61-B2.1), particularly in patients with complete sacral fractures. We hypothesized that nonoperative treatment would result in acceptable functional outcomes.

DESIGN

Database review.

SETTING

Level I trauma center.

PATIENTS

We identified patients treated for LC1 fractures (n = 406) from 2007 to 2011 and analyzed a subset of LC1 injuries of "intermediate severity" characterized by complete sacral fracture with less than 1 cm initial displacement (n = 104).

INTERVENTION

Fifty patients were contacted for functional outcome assessment at average follow-up of 33 months.

MAIN OUTCOME MEASURES

Majeed pelvic score and physical component summary (PCS) score and mental component summary (MCS) score of 12-item Short-Form Health Survey version 2.

RESULTS

Average Majeed pelvic score was 85.5, yielding 33 excellent, 9 good, 5 fair, and 3 poor outcomes. Mean PCS and MCS scores were 48.8 and 48.9, respectively (both confidence intervals include 50, the score for a healthy normative population). Patients with lower extremity injuries had a trend toward lower PCS and MCS and statistically significant lower mean Majeed scores (P = 0.01). Thirty-five of 37 patients without lower extremity injury had good or excellent categorical outcomes based on Majeed scores. No significant differences were observed regarding weight-bearing status, extent of anterior ring injury, or injury severity score. Radiographic follow-up was available for 36 of 50 patients. No fracture was displaced >1 cm.

CONCLUSIONS

Acceptable functional outcomes can be expected after nonsurgical management of LC1 pelvic injuries with complete sacral fracture and less than 1 cm initial displacement.

LEVEL OF EVIDENCE

Therapeutic level IV.

Radiological findings correlate with neurological deficits but not with pain after operatively treated sacral fractures

BACKGROUND AND PURPOSE

Neurological deficits and pain are common after displaced sacral fractures. However, little is known about the association between the long-term clinical outcomes and radiological findings. We examined the long-term radiological findings and their correlations with lumbosacral pain and neurological deficits in the lower extremities after surgery for sacral fractures.

METHODS

28 consecutive patients with operatively treated displaced sacral fractures were followed for mean 11 (8-13) years. Sensorimotor impairments of the lower extremities were classified according to the American Spinal Injury Association (ASIA). Pain was assessed using a visual analog scale (VAS). All patients underwent conventional radiographic examination and CT, and the images were scrutinized for nonunion, residual displacement, narrowing of the sacral foramina, and post-foraminal encroachment of the L5 and S1 nerves.

RESULTS

There was residual displacement of ≥ 10 mm in 16 of the 28 patients. 26 patients had narrowing of 1 or more neural root foramina in L5-S4. 8 patients reported having no pain, 11 had pain only in the lumbosacral area, and 9 had pain in combination with radiating leg pain. Statistically significant correlations were found between narrowing of the sacral foramina and neurological deficits in the corresponding dermatomes. Significant correlations were also found between post-foraminal encroachment of L5 nerves and both sensory and motor deficits. No correlations were found between pain and radiological findings.

INTERPRETATION

Pathological radiological findings are common 11 years after operatively treated displaced sacral fractures. Sacral foraminal and L5 post-foraminal bony encroachments were common findings and correlated with neurological deficits. However, lumbosacral pain did not correlate with radiological sequelae after fracture healing.

Radiographic displacement in pelvic ring disruption: reliability of 3 previously described measurement techniques

BACKGROUND

The literature on pelvic ring disruptions is based largely on nonstandardized and nonvalidated radiographic outcomes. A thorough review of the literature revealed only 3 described methods for measuring radiographic displacement and 1 frequently used grading system for displacement. We aimed to test the reliability of these previously published radiographic measurement methods and grading system.

METHODS

Five separate observers measured radiographic displacement on the standardized pre- and postoperative anteroposterior, inlet, and outlet views of 25 patients with surgically treated Tile B and C pelvic fractures. The readers measured their initial impression based on the Tornetta and Matta grading system (excellent, good, fair, and poor). Next, they measured displacement using the inlet and outlet ratio as described by Sagi, the cross measurement technique as described by Keshishyan, and the absolute displacement method (ADM) as described by Lefaivre. The millimeter measurement obtained by the ADM was converted using the Tornetta and Matta grading system. Each continuous measure was compared for interobserver reliability using intraclass correlations (ICCs), and the categorical outcomes were compared using a kappa statistic. Finally, the relationship of the initial impression to the grade as determined by the ADM was compared using kappa agreement.

RESULTS

The agreement among observers based on initial impression was poor (kappa statistic, 0.306) but was fair among those reductions that were excellent (κ = 0.495). Using the Sagi method, the reliability ICC was moderate for the postoperative inlet [0.515, 95% confidence interval (CI), 0.338-0.702] and outlet ratio (0.594, 95% CI, 0.423-0.760) but almost perfect in preoperative radiographs (inlet: 0.814, 95% CI, 0.703-0.901; outlet: 0.863, 95% CI, 0.775-0.929). The ICCs for all interpretations of the Keshishyan technique were excellent but were highest when considered as a ratio (preoperative: 0.938, 95% CI, 0.894-0.969; postoperative: 0.912, 95% CI, 0.850-0.955). Using the ADM, the location and film used for measurement had poor agreement, and the ICC for the measurement in millimeters was moderate (preoperative: 0.522, 95% CI, 0.342-0.708; postoperative: 0.432, 95% CI, 0.255-0.634) and the kappa agreement poor when converted using the Tornetta and Matta scale (κ = 0.2190). The agreement between the impression and the converted grade from the ADM was poor (κ = 0.2520).

CONCLUSIONS

Radiographic measurement in pelvic x-rays to date has been nonvalidated, and we found the interobserver reliability on common methods, including overall impression and absolute displacement in millimeters, to be poor. The inlet/outlet ratio as described by Sagi was reliable only with wide displacement. The cross measurement technique allows least observer choice and had excellent reliability but does not give a measurement that we can easily interpret based on convention in pelvic fracture description.

Two-leg alternate loading model--a different approach to biomechanical investigations of fixation methods of the injured pelvic ring with focus on the pubic symphysis

The dorsal component of the pelvic ring is considered to be the most essential element for the stability of the pelvic ring. None of the current biomechanical set-ups include the effect of shear stresses by alternating loads that the pelvic ring has to withstand during walking. We hypothesize that a biomechanical test set-up with two-leg alternate loading will lead to stress imitation at the pubic symphysis that are more similar to existing strains than other test set-ups, and would, therefore, be more adequate for biomechanical testing of fixation methods. A new biomechanical two-leg standing test set-up with an alternate pelvic loading was constructed and was validated with six human pelvises from fresh frozen cadavers. Three-dimensional motion tracking was performed. The specimens were subjected to a non-destructive quasi-static test and a non-destructive cyclic test with progressive load amplitude from 170 N to 340 N over 1000 cycles. The initial rotational 'range of motion' and 'mean displacement' around the vertical axis for a pre-load of 170 N was about 0.3° and 0.2°, respectively, increasing by 0.1-0.2° at a load of 340 N. The rotation around the vertical axis and the translation along the frontal horizontal axis confirmed the stability of the pubic symphysis. The rate of ascend of displacements decreased, once the rotation reached 1° or the translation reached 1mm. The current biomechanical test set-up was compared with previous clinical findings, and the method was found valid for measuring inter-segmentary movements at the pubic symphysis.

The posterior approach to pelvic ring injuries: A technique for minimizing soft tissue complications

Surgical techniques and fixation strategies for the treatment of unstable posterior pelvic ring injuries continue to evolve. The safety of the posterior surgical approach in particular has been questioned due to historically high rates of wound related complications. More contemporary studies have shown lower infection rates, however concern still persists. These concerns for infection and wound necrosis have led, in part, to increased interest in closed reduction and percutaneous fixation for treatment of these injuries but an open posterior approach remains the optimal strategy in some injury patterns. We describe herein a modified posterior approach to the pelvis designed to minimize wound related complications and present our clinical results demonstrating wound complication rates consistent with contemporary publications.

Accuracy in radiographic assessment of pelvic ring fracture deformity: analysis of current methods

OBJECTIVES

To our knowledge, measuring pelvic ring displacement on plain radiographs has not been scientifically evaluated. This study aims to assess the validity and reliability of existing measurement systems utilizing plain radiographs.

METHODS

A Sawbones model, validated as part of this study, was fractured in a controlled fashion to simulate known pelvic ring fracture patterns. Computed tomographic scans with 2- and 3-dimensional reconstructions of intact and injury models were obtained to measure the "true" displacement of anterior and posterior disrupted surfaces. The computed tomographic data set was used to create computer-reconstructed radiographs (CRR) simulating standard anteroposterior, inlet and outlet views. Currently described measurement techniques were utilized by 8 senior orthopaedic residents and 3 fellowship-trained orthopaedic trauma surgeons on the computer-reconstructed radiograph of each model. These measurements were than assessed for interobserver reliability and validity.

RESULTS

Average observer measurements of anterior symphysis diastasis and vertical translation had good validity and reliability with each having an average confidence interval of 4.6 mm. The observer measurements of sacroiliac (SI) joint displacement were significantly less reliable with average confidence interval of 5.8 mm. Kappa correlation calculations for whether the SI joint was displaced more than 1 cm showed an overall agreement of 0.702 and kappa coefficient of 0.404.

CONCLUSIONS

Computer-reconstructed radiographic, and thus plain radiographic, assessments of deformity at the SI joint have poor reliability and accuracy. Clinicians should recognize these limitations when measuring pelvic displacement of the SI joint and cautiously interpret clinical results of treatment of SI joint injuries where displacement is measured on plain radiographs.