The Association of Jumbo Femoral Heads and Acetabular Cup Position on Patient Outcomes After Modern Posterior Approach Total Hip Arthroplasty.

Abstract

Use of jumbo femoral heads (≥ 40 mm) in total hip arthroplasty decreases postoperative dislocation; however, may leave patients more susceptible to groin pain. Limited data exist for the effect of jumbo femoral heads and acetabular cup position on modern patient-reported outcome measures (PROMs). This study evaluated the effect of jumbo femoral heads and acetabular cup position on PROMs after primary total hip arthroplasty. A total of 328 consecutive primary THAs of a single implant system with various femoral head sizes (36% ≥ 40 mm) were retrospectively reviewed. Acetabular cup inclination and anteversion were radiographically measured. Demographics, comorbidities, and implant sizes were documented. Prospectively collected University of California Los Angeles Activity Level, Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR), and satisfaction were evaluated. The mean follow-up was 1.2 years (range, one to five). A P-value of 0.05 was considered statistically significant. Femoral head size was not associated with University of California Los AngelesActivity Level scores at any time point (P ≥ 0.209). Independent of patient sex, the mean HOOS JR score was significantly higher in the ≥ 40 mm femoral head group compared to the < 40 mm head group at 4 months although not reaching a clinically significant threshold (mean difference 4.4, 95% CI [confidence interval]: 0.5 to 8.3, P = 0.027); however, mean scores at the latest follow-up were not different (P = 0.956). The HOOS JR scores ≥ 90 and being "very satisfied or satisfied" were associated with a wide range and several combinations of acetabular cup inclination and anteversion. A total of 88.9% of patients reported being "very satisfied or satisfied" at the latest follow-up. Patients achieved comparable PROMs regardless of femoral head size, suggesting large femoral heads may not leave patients susceptible to groin pain in addition to reducing the risk of postoperative dislocation. Excellent patient outcomes correlated with wide ranges of acetabular cup positions. III.