Comparison of percutaneous cross screw fixation versus open reduction and internal fixation for pelvic Day type II crescent fracture-dislocation: case-control study

Anterior Sacroiliac Fracture Dislocation: A Comparative Radiologic analysis of Crescent Fractures in Pelvic Ring Injuries: A Retrospective Study

Background and Objectives: Anterior sacroiliac fracture dislocation (ASFD), also known as locked pelvis, is a rarely reported diagnosis. The types of ASFDs are often misdiagnosed as lateral compression fractures due to the presence of crescent fractures. In this study, we distinguished ASFD from lateral compression fractures (LC 2) and studied their characteristics. Materials and Methods: This is a retrospective study involving patients from a Level 1 trauma center. Fifty-nine patients under the age of 65 years with crescent fractures caused by a high-energy mechanism were investigated. Results: The incidence of ASFD was 25% (15 of 59) in patients with crescent fractures. Among the 15 patients, 6 had override of the ilium over the sacrum, inhibiting reduction in the sacroiliac joint. Pre-operative radiographic evaluations revealed that vertical displacement of the ASFD was larger than that of lateral compression fracture (LC 2) in the outlet view (mean 9.5 vs. 1.9 mm, p = 0.013), and the pelvic asymmetry ratio was larger in ASFD (mean 7.8 vs. 4.1, p = 0.006) in the pelvis AP view. All patients achieved union after surgery. Post-operative radiography showed no significant vertical displacement difference. There was no difference in vascular injury or hemodynamic instability requiring embolization or preperitoneal pelvic packing (PPP) between the two groups. Conclusions: Patients with ASFD have greater vertical displacement and asymmetry compared to patients with LC 2 fractures. These fractures must be distinguished for appropriate reduction and anterior plate fixation.

Open reduction and internal fixation of crescent fracture-dislocation: anterior or posterior approach?

INTRODUCTION

To date, the approach that prevails in the open reduction and internal fixation of crescent fracture-dislocations (CFD) remains unknown. This study aimed to compare the outcomes of CFD treated via the anterior or posterior approach.

MATERIALS AND METHODS

Data from 64 cases of CFDs openly reduced through an anterior (group A, n = 31) or a posterior (group B, n = 33) approach were retrospectively analyzed. Functional results, reduction quality, residual displacements in the axial and coronal planes, pelvic asymmetry deformity, and correlations between Day's classification were compared. Complications and fracture union were also recorded. All patients were followed up for at least 12 months.

RESULTS

The functional scores were similar between the two groups, and all fractures achieved good or excellent reduction postoperatively. In the coronal plane, the excellent/good ratio in group B was higher than in group A. The mean residual displacement in the coronal plane was significantly higher in group A than in group B, with group A showing greater displacement in both planes for Day I fractures and in the coronal plane for Day II fractures. The residual displacement in both planes for Day III fractures was comparable between the groups. The pelvic asymmetry deformity was equal between the two groups and among the different Day's fracture types.

CONCLUSIONS

Open reduction and internal fixation of CFDs obtained satisfactory outcomes through an anterior or posterior approach. The posterior approach achieved a better sacroiliac joint reduction. The optimal indication for the posterior approach was a Day I fracture, followed by a Day II fracture. No correlation was found between the surgical approach and reduction quality in Day III fractures.

[Finite element analysis of five internal fixation modes in treatment of Day type crescent fracture dislocation of pelvis]

Objective

To compare the biomechanical differences among the five internal fixation modes in treatment of Day type Ⅱ crescent fracture dislocation of pelvis (CFDP), and find an internal fixation mode which was the most consistent with mechanical principles.

Methods

Based on the pelvic CT data of a healthy adult male volunteer, a Day type Ⅱ CFDP finite element model was established by using Mimics 17.0, ANSYS 12.0-ICEM, Abaqus 2020, and SolidWorks 2012 softwares. After verifying the validity of the finite element model by comparing the anatomical parameters with the three-dimensional reconstruction model and the mechanical validity verification, the fracture and dislocated joint of models were fixed with S 1 sacroiliac screw combined with 1 LC-Ⅱ screw (S 1+LC-Ⅱ group), S 1 sacroiliac screw combined with 2 LC-Ⅱ screws (S 1+2LC-Ⅱ group), S 1 sacroiliac screw combined with 2 posterior iliac screws (S 1+2PIS group), S 1 and S 2 sacroiliac screws combined with 1 LC-Ⅱ screw (S 1+S 2+LC-Ⅱ group), S 2-alar-iliac (S 2AI) screw combined with 1 LC-Ⅱ screw (S 2AI+LC-Ⅱ group), respectively. After each internal fixation model was loaded with a force of 600 N in the standing position, the maximum displacement of the crescent fracture fragments, the maximum stress of the internal fixation (the maximum stress of the screw at the ilium fracture and the maximum stress of the screw at the sacroiliac joint), sacroiliac joint displacement, and bone stress distribution around internal fixation were observed in 5 groups.

Results

The finite element model in this study has been verified to be effective. After loading 600 N stress, there was a certain displacement of the crescent fracture of pelvis in each internal fixation model, among which the S 1+LC-Ⅱ group was the largest, the S 1+2LC-Ⅱ group and the S 1+2PIS group were the smallest. The maximum stress of the internal fixation mainly concentrated at the sacroiliac joint and the fracture line of crescent fracture. The maximum stress of the screw at the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 2AI+LC-Ⅱ group. The maximum stress of the screw at the ilium fracture was the largest in the S 1+2PIS group and the smallest in the S 1+2LC-Ⅱ group. The displacement of the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 1+S 2+LC-Ⅱ group. In each internal fixation model, the maximum stress around the sacroiliac screws concentrated on the contact surface between the screw and the cortical bone, the maximum stress around the screws at the iliac bone concentrated on the cancellous bone of the fracture line, and the maximum stress around the S 2AI screw concentrated on the cancellous bone on the iliac side. The maximum bone stress around the screws at the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 2AI+LC-Ⅱ group. The maximum bone stress around the screws at the ilium was the largest in the S 1+2PIS group and the smallest in the S 1+LC-Ⅱ group.

Conclusion

For the treatment of Day type Ⅱ CFDP, it is recommended to choose S 1 sacroiliac screw combined with 1 LC-Ⅱ screw for internal fixation, which can achieve a firm fixation effect without increasing the number of screws.

Lateral Compression Type 2 Pelvic Fractures-A Clinical Study of Fracture Displacement Measurement and Closed Reduction

Objective

To evaluate the displacement in four lateral compression type 2 (LC2) fracture subtypes (iliac wing and three kinds of crescent fractures) and to investigate the appropriate closed reduction for treatment using a pelvic reduction frame.

Methods

A total of 71 patients with LC2 pelvic fractures from February 2014 to November 2019 were included in this retrospective cohort study. Preoperative X‐ray and computed tomography data were used to assess the direction of the fracture displacement and the sacroiliac joint dislocation. The fractures in all patients were reduced with a pelvic reduction frame and fixed with percutaneous screws as well as an anterior subcutaneous pelvic ring internal fixator. Two different closed reduction strategies were adopted, one was first longitudinal traction and then transverse traction, the other was first transverse traction then longitudinal and LC2 traction. The Matta score system was used to evaluate the postoperative X‐ray and the Majeed score system was used for follow‐up evaluation.

Results

A total of 13 iliac wing fractures (86.7%) and 16 Day type 1 fractures (94.1%) were vertically stable with only internal displacement, the ring width displacements were 5 (3, 8.75) and 8 (4, 12) mm, the posterior superior iliac spine (PSIS) differences were 0 (0, 0) mm and 0 (0, 0) mm. A total of 21 Day type 2 fractures (95.5%) and 16 Day type 3 fractures (94.1%) were characterized by cephalic and dorsal fracture dislocation on the basis of internal displacement, the ring width displacements were 6 (4.25, 12) and 4 (0, 7.5) mm and the PSIS differences were 4 (2, 5) and 0 (0, 3.75) mm. Based on the Matta scores, excellent reduction was achieved in 51 patients, good reduction in 17 patients, and poor reduction in three patients. The average Majeed score was 91.6, with a minimum outpatient follow‐up of 12 months (average 31.6 months).

Conclusion

LC2 fractures involve two different kinds of fracture displacement: internal displacement only and a combination of internal, cephalic, and dorsal dislocation through the sacroiliac joint. Good clinical outcomes can be achieved for LC2 fractures using two different closed reduction strategies.