Reza Firoozabadi1, Benjamin Hamilton2, Paul Toogood3, Milton Chip Routt4, Dave Shearer3. 1. Department of Orthopaedic Surgery and Sports Medicine, Harborview Medical Center, Seattle, WA. 2. Department of Medicine, Emergency Medicine, University of Washington Medical Center, Seattle, WA. 3. Department of Orthopaedics, University of California, Orthopaedic Trauma Institute, San Francisco, CA. 4. Department of Orthopaedic Surgery, The University of Texas Medical School at Houston, Houston, TX.
Abstract
OBJECTIVES: Identify risk factors for early conversion to total hip arthroplasty (THA) in an effort to aid in counseling patients and selecting the optimal treatment for patients who sustain a fracture involving the posterior wall of the acetabulum. DESIGN: Retrospective cohort analysis. SETTING: Level I trauma center. PATIENTS: Patients with acetabular fractures involving the posterior wall managed with open reduction internal fixation at least 4 years out from surgery. INTERVENTION: Preoperative and postoperative computed tomography scans were reviewed for injury characteristics and reduction quality. Participants were contacted by telephone to document reoperations and functional outcomes including the SF-8 and modified Merle d'Aubigne Hip Scale. MAIN OUTCOME MEASURE: Conversion to THA. RESULTS: The overall rate of conversion to THA was 5% at 2 years, 14% at 5 years, and 17% at 9 years. Presence of 5 specific radiographic features was associated with a 50% rate of conversion to THA in contrast to 11% if 4 or less features were present. Among cases with less than 1 mm of diastasis/step-off on postoperative computed tomography scan, there were no THA conversions, 10% conversion for 1-4 mm, and 54% if 4 mm or more of malreduction. There was no difference in SF-8 or modified Merle d'Aubigne scores comparing patients who underwent THA and those who did not. CONCLUSIONS: Acetabular fractures with posterior wall involvement are associated with a significantly higher rate of conversion to THA if reduction is not near-anatomic. A combination of clinical/radiographic findings is associated with poorer reductions and higher rate of conversion to THA. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
OBJECTIVES: Identify risk factors for early conversion to total hip arthroplasty (THA) in an effort to aid in counseling patients and selecting the optimal treatment for patients who sustain a fracture involving the posterior wall of the acetabulum. DESIGN: Retrospective cohort analysis. SETTING: Level I trauma center. PATIENTS: Patients with acetabular fractures involving the posterior wall managed with open reduction internal fixation at least 4 years out from surgery. INTERVENTION: Preoperative and postoperative computed tomography scans were reviewed for injury characteristics and reduction quality. Participants were contacted by telephone to document reoperations and functional outcomes including the SF-8 and modified Merle d'Aubigne Hip Scale. MAIN OUTCOME MEASURE: Conversion to THA. RESULTS: The overall rate of conversion to THA was 5% at 2 years, 14% at 5 years, and 17% at 9 years. Presence of 5 specific radiographic features was associated with a 50% rate of conversion to THA in contrast to 11% if 4 or less features were present. Among cases with less than 1 mm of diastasis/step-off on postoperative computed tomography scan, there were no THA conversions, 10% conversion for 1-4 mm, and 54% if 4 mm or more of malreduction. There was no difference in SF-8 or modified Merle d'Aubigne scores comparing patients who underwent THA and those who did not. CONCLUSIONS: Acetabular fractures with posterior wall involvement are associated with a significantly higher rate of conversion to THA if reduction is not near-anatomic. A combination of clinical/radiographic findings is associated with poorer reductions and higher rate of conversion to THA. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.