Outcomes following staged bilateral total hip replacement: does first-side surgery predict the second?

Abstract

Introduction Patient-reported outcome measures (PROMs) for bilateral staged total hip replacements (THRs) were reviewed to determine whether first-side surgery can predict second-side outcomes. Methods A retrospective review was undertaken of a consecutive cohort of staged bilateral THRs using the same approach, implant and technique, from August 2009 to February 2020. Minimal important change (MIC) in PROMs was set at ≥5. Results A total of 296 consecutive staged bilateral THRs were performed in 148 patients. Mean time interval between sides was 25 months (range 2–102). Mean age was 63.2 years for the first side and 65.3 years for the second; 62.8% of patients were female. Mean body mass index was 31.08 for the first side, increasing to 31.57 for the second side (p = 0.248). One-year follow-up PROMs were available for 96.6% and 92.5% of the first and second side, respectively. Mean PROMs improvement at 1 year was 26.4 for the first side and 25.1 for the second side (p = 0.207). Some 97.9% of patients achieved MIC for the first side and 96.3% for the second side (p = 0.092). Eight patients failed to reach an MIC on one side, all were female (p < 0.001); however, MIC was achieved for the contralateral side. Seven of eight patients (87.5%) achieved MIC by 2 years. Conclusions This study identified no significant difference between first- and second-side PROMs improvements following staged bilateral THRs at 1-year follow-up. Failure to reach MIC on one side does not preclude success on the other. Female patients were more prone to not reach MIC at 1 year, but improvement was still subsequently achieved in the majority of cases. The informed consent process is able to reflect this expectation.