The influence of migration of the exeter V40 stem on patient reported outcome measures: a 2-year follow-up of 112 total hip arthroplasties using radiostereometric analysis

Purpose: The cemented Exeter V40 stem is known to migrate distally. Several previous studies have reported on the extent of stem migration and its influence on clinical outcome. However, no studies have investigated the influence of stem migration on Patient Reported Outcome Measures (PROM). Methods: One hundred and twelve total hip arthroplasties (THA) were included in a 2-year follow-up using Radiostereometric Analysis (RSA). Patients were evaluated using the Oxford Hip Score (OHS) and EQ-5D-3L PROMs. The purpose of this study was to assess the influence of stem migration, measured by Maximum Total Point Motion (MTPM), on the 2-year postoperative score (OHS and EQ-5D). Furthermore, the influence of pre-operative PROM, age, gender, acetabular component and BMI was associated with the 2-year postoperative OHS and EQ-5D scores. Results: MTPM was a non-significant predictor of the 2-year postoperative OHS (regression coefficient (B) = − 2.38 (CI − 5.44;.69)) and of the 2-year postoperative EQ-5D (B = − .01 (CI − .04;.02)). The only significant predictor of the 2-year postoperative OHS and 2-year postoperative EQ-5D was gender (B = 8.71 (CI 3.52; 13.90)) and (B =.13 (CI.07;.18)), respectively. Conclusion: Stem migration did not significantly influence PROMs at 2 years post-operatively. Using a patient-focused approach, our results seem to corroborate results reported by previous studies, showing that slow migration of the Exeter V40 stem does not seem to influence the clinical outcome.