Risk of Total Hip Arthroplasty After Acetabular Fracture Fixation: The Importance of Age

BACKGROUND: Geriatric patients are the most rapidly growing cohort of patients sustaining acetabular fractures (AFs). The purpose of this study was to examine the risk of a secondary total hip arthroplasty (THA) in older patients (>60 year old) with a prior AF open reduction internal fixation (ORIF) compared with younger patients (<60 year old) with an AF ORIF on a large population level. METHODS: Using administrative health care data from 1996 to 2010 inclusive of all 202 hospitals in Ontario, Canada, all adult patients with an AF ORIF and a minimum of two year follow-up were identified and included. The risk of THA was examined using a Cox proportional hazards model adjusting for patient risk factors. Secondary outcomes included surgical complications and all-cause mortality. RESULTS: A total of 1725 patients had an AF ORIF; 1452 (84.2%, mean age of 38.3 ± 12.1 years) aged <60 years ("younger") and 273 (15.8%, mean age of 69.9 ± 7.8 years) > 60 years ("older"). The mean (SD) follow-up time for all patients was 6.9 (4.2) years. In older patients, 19.4% (53 of 273) went on to receive a secondary THA with a median time to event of 3.9 years, compared with 12.9% (187 of 1452) in the younger patient cohort with a median time of 6.9 years (HR 1.7, 95% CI: 1.2-2.3). As expected, older patients had a higher 90-day mortality rate compared with younger patients (7.7% vs. 0.7%, respectively; HR 9.2, 95% CI: 4.3-19.9; P < .001). CONCLUSION: Older patients with an AF ORIF are at a significantly higher risk for a secondary THA than younger patients with an AF ORIF.