Post-Traumatic Hip Osteoarthritis after Pelvic Ring Injuries.

Objectives: While rates of post-traumatic 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 post-traumatic hip osteoarthritis in pelvic ring injury patients. It was hypothesized that more severe pelvic ring injuries would be associated with greater rates of post-traumatic hip osteoarthritis.

Methods: Design : Retrospective Cohort.

Setting: Urban/Suburban Academic Level I Trauma Center.

Patient selection criteria: Subjects were identified using a retrospective search for AO/OTA type A, B, and C pelvic ring injuries. Patients were included if they were age 18 or greater, had a pelvic ring injury, and one year or more of radiographic follow-up. Patients were excluded if they had prior total or hemi-arthroplasty of either hip, 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, 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 and 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. 127 patients underwent non-operative 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 post-traumatic osteoarthritis (PTOA) based on the Young-Burgess injury classification (44.4% of LC III versus 11.1% of LC I pelvic ring injury patients, p < 0.001).

Conclusions: A significant frequency of post-traumatic osteoarthritis after pelvic ring injuries was identified. A higher rate of preogression to PTOA was found with unstable injuries compared with stable pelvic injuries.

Level of evidence: III, Retrospective Cohort Study.