Background: This study reports the long-term survivorship of primary total hip arthroplasty (THA) for protrusio acetabuli. Methods: Patients undergoing THA utilising cement and bone graft acetabular reconstruction for protrusio acetabuli in a university teaching hospital during the period 2003 to 2014 were included. Kaplan-Meier survival estimates were calculated with 95% confidence intervals (CI) up to 15 years following surgery. PROMs were collected pre- and post-operatively for hip-specific function (Oxford Hip Score [OHS]) and health-related quality of life (HRQoL) using the EQ-5D-3L. Results: 129 consecutive THAs (96 patients) performed for protrusio acetabuli were identified (median age 69, IQR 61-75; female 115 [89.1%]; 38 [29.5%] inflammatory arthritis) with a mean follow-up of 15.7 years (range: 10.1-20.1 years). At the final follow-up, fifty-six (43.4%) patients had died and there were eleven (8.5%) reoperations, of which eight (6.2%) involved the revision of the acetabular component. The fifteen-year Kaplan-Meier any-reoperation survival estimate was 91.3% (95% CI 85.9-97.0). When considering all-cause acetabular revision only, the 15-year survival estimate was 93.1% (95% CI 88.2-98.3). The median pre-operative OHS improved significantly from baseline to 1 year post-THA, beyond the minimal important change (mean difference 28, 95% CI 25-30, p < 0.001). Similarly, there were clinically relevant improvements in HRQoL at 1 year post surgery (mean difference 0.10, 95% CI 0.06-0.15, p < 0.001). Conclusions: This study demonstrates that primary cemented THA utilising acetabular bone graft for reconstruction in patients with protrusio acetabuli was associated with 15-year survival rates of 93.1% and clinically relevant improvements in hip-specific function and HRQoL.
Keywords: arthroplasty; hip; outcome; protrusio acetabuli.