Abstract

Background: Acetabular fracture remains as a major challenge to orthopaedic surgeons despite of decades of improvement in its operative management. Unfavorable reduction is considered one of the key factors leading to joint degeneration and compromised clinical outcome in acetabular fracture patients. Besides the columns, walls, and superior dome, the postoperative position of hip joint center (HJC), which is reported to affect hip biomechanics, should be considered during the assessment of quality of reduction. Objectives: In this study, we aimed to quantify the postoperative shift of HJC radiographically, and to evaluate the relationship between the shift of HJC and the quality of fracture reduction following ORIF of acetabular fractures. Material and Methods: Patients with a displaced acetabular fracture that received open reduction and internal 􀃶xation in the authors' institution during the past three years were identi􀃶ed from the trauma database. The horizontal and vertical shifts of HJC were measured in the standard anteroposterior view radiographs taken postoperatively. The radiographic quality of fracture reduction was graded according to Matta's criteria. The relationships between the shift of HJC and the other variables were evaluated. Results: Totally 95 patients with 36 elementary and 59 associated-type acetabular fractures were included, wherein the majority showed a medial (92.0%) and proximal (94.0%) shift of HJC postoperatively. An average of 2.9 mm horizontal and 2.3 mm vertical shift of HJC were observed, which correlated signi􀃶cantly with the quality of fracture reduction (P < 0.001 for both). The horizontal shift of HJC correlated with the fracture type (P = 0.022). Conclusion: The restoration of HJC correlates with the quality of reduction in acetabular fractures following open reduction and internal 􀃶xation. Further studies are required to address the effects of HJC shift on the biomechanical changes and clinical outcomes of hip joint, especially in poorly reduced acetabular fractures.

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