Abstract / Summary
Objective: To compare the magnitude of subsidence between single- (SW) and double-wedge (DW) femoral stems in primary total hip arthroplasties (THA), and to identify factors associated with clinically relevant subsidence.
Methods: Retrospective cohort study with 82 patients (164 hips) undergoing bilateral THA between 2012 and 2022, each receiving type I (Corail) and type II (Summit) stems. Subsidence was measured radiographically up to 6 months postoperatively and was considered clinically relevant when greater than 3 mm. Radiographic variables included cortical enlargement index (CEI) and canal fill rate (CFR). Statistical analyses included paired t-test, logistic regression, and Spearman correlation.
Results: The mean subsidence was 1.93 ± 1.16 mm in type I stems and 2.23 ± 1.57 mm in type II ( p = 0.181). Clinically relevant subsidence occurred in 18.2% of type I stems and 31.7% of type II (OR = 2.07; p = 0.050). Greater subsidence was observed in the first surgery in bilateral arthroplasties ( p = 0.006). There was no significant correlation between subsidence, age, body mass index (BMI), CEI, or CFR.
Conclusion: The double-wedge stems were associated with a higher risk of clinically relevant subsidence. In bilateral THA, subsidence is more pronounced at first surgery, with no detectable influence of demographic or radiographic factors.