Examining the "revisability" benefit of hip resurfacing arthroplasty.

Background: Hip resurfacing arthroplasty (HRA) is an alternative to total hip arthroplasty (THA) that is typically reserved for young active patients because it preserves bone. However, the benefits of HRA only hold true if conversion THA after failed HRA provides acceptable outcomes.

Aim: To compare patient reported outcomes for conversion THA after HRA failure to primary THA.

Methods: A retrospective review of 36 patients (37 hips) that underwent conversion THA for failed HRA between October 2006 and May 2019 by a single surgeon was performed. Patient reported outcomes [modified Harris Hip Score (mHHS), University of California Los Angeles (UCLA) activity score] were obtained an email-based responder-anonymous survey. Outcomes were compared to normative data of a primary THA cohort with similar demographics. Subgroup analysis was performed comparing outcomes of conversion THA for adverse local tissue reaction (ALTR) all other causes for failure.

Results: The study group had a lower mHHS than the control group (81.7 ± 13.8 90.2 ± 11.6, < 0.01); however, both groups had similar UCLA activity levels (7.5 ± 2.3 7.2 ± 1.6, = 0.51). Patients that underwent conversion for non-ATLR causes had similar mHHS (85.2 ± 11.5 90.2 ± 11.6, = 0.11) and higher UCLA activity levels (8.5 ± 1.8 7.2 ± 1.6, < 0.01) compared to the control group. Patients that underwent conversion for ATLR had worse mHHS (77.1 ± 14.5 90.2 ± 11.6, < 0.01) and UCLA activity levels (6.1 ± 2.3 7.2 ± 1.6, = 0.05) when compared to the control group.

Conclusion: Patient outcomes equivalent to primary THA can be achieved following HRA conversion to THA. However, inferior outcomes were demonstrated for ALTR-related HRA failure. Patient selection and perhaps further studies examining alternative HRA bearing surfaces should be considered.