Ethnic and sex-specific differences in proximal femoral geometry and its implications for prosthetic design in total hip arthroplasty - A systematic analysis.

Restoration of proximal femoral geometry is critical for total hip arthroplasty (THA) success, yet ethnic and sex-based morphological variations remain inadequately characterised. This systematic review synthesises morphometric evidence across multiple ethnic cohorts to inform implant design and surgical planning. A 3-year systematic review was conducted at Yenepoya Medical College (June 2022-present), searching multiple databases for studies reporting proximal femoral parameters in Chinese, Korean, Japanese, European, and Brazilian populations using radiography and 3D-CT imaging. An in-vivo Indian cohort of 96 hips was included for clinical correlation. Studies lacking ethnic/sex stratification, involving pediatric populations, or with inadequate methodology were excluded. Quality assessment used the Newcastle-Ottawa Scale (≥6 points retained). Sex-stratified data extraction was performed using fixed/random-effects meta-analyses, with meta-regression evaluating ethnicity and sex as predictors of geometric parameters (α = 0.05). Six studies were analyzed, representing six ethnic populations plus one in-vivo cohort (n = 727 femurs). Korean males showed the largest femoral head diameter (48.50 ± 2.23 mm) compared to Brazilian males (31.1 ± 2.7 mm), a 17.4 mm disparity. Neck-shaft angles varied between 126.35° and 132.1° across populations. Chinese females exhibited the highest anteversion (29.03 ± 2.73°) versus males (11.66 ± 1.55°), representing a 149 % difference. Brazilian populations displayed minimal sexual dimorphism (<2 %). Indian CT measurements revealed systematically lower head diameter values compared to radiography (43.0 ± 2.6 vs 48.4 ± 2.6 mm in males). Substantial ethnic and sex-specific differences in proximal femoral geometry necessitate ethnicity-conscious and sex-specific implant modularity or customization to prevent offset under-restoration, impingement, and accelerated bone resorption, rather than relying on universal implant designs.