Posttraumatic Hip Osteoarthritis After Pelvic Ring Injuries.

OBJECTIVES

While rates of posttraumatic osteoarthritis after acetabulum fracture have been thoroughly studied, there has been less emphasis on hip osteoarthritis after pelvic ring injuries. The objective of this study was to determine the frequency of posttraumatic hip osteoarthritis in pelvic ring injury patients. It was hypothesized that more severe pelvic ring injuries would be associated with greater rates of posttraumatic hip osteoarthritis.

DESIGN

Retrospective Cohort.

SETTING

Urban/Suburban Academic Level I Trauma Center.

PATIENT SELECTION CRITERIA

Subjects were identified using a retrospective search for OTA/AO type A, B, and C pelvic ring injuries. Patients were included if they were aged 18 years or older, had a pelvic ring injury, and had 1 year or more of radiographic follow-up. Patients were excluded if they had prior total hip arthroplasty or hip hemiarthroplasty, femoral neck fracture, acetabulum fracture, femoral head fracture, or inadequate radiographic follow-up.

OUTCOME MEASURES AND COMPARISONS

Both hips were graded using the Tönnis classification at the time of injury and available follow-up pelvis films. Comparison of rate of osteoarthritis progression was made between stable (LC I injuries stable on examination under anesthesia, all APC I injuries) and unstable (APC II, APC III, LC II, LC III, and LC I injuries unstable on examination under anesthesia) pelvic ring injury patients, as well as severity of injury using the Young-Burgess classification.

RESULTS

Two hundred eleven patients were included for final analysis. Average age was 58.8 years (SD 28.1 years, range 18-100 years). Eighty-eight patients (41.7%) were male. One hundred twenty-seven patients underwent nonoperative management, and 84 underwent surgical stabilization. 34.5% (29/84) of patients with unstable pelvic ring injuries and 6.2% (8/127) of patients with stable pelvic ring injuries demonstrated progression of osteoarthritis on the ipsilateral side of their injury ( P < 0.001). More severe pelvic ring injury patterns had a greater rate of posttraumatic osteoarthritis (PTOA) based on the Young-Burgess injury classification (44.4% of LC III vs. 11.1% of LC I pelvic ring injury patients, P < 0.001).

CONCLUSIONS

A significant frequency of posttraumatic osteoarthritis after pelvic ring injuries was identified. A higher rate of progression to PTOA was found with unstable injuries compared with stable pelvic injuries.

LEVEL OF EVIDENCE

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