Oblique Bikini Incision Versus Longitudinal Incision for Direct Anterior Approach Total Hip Arthroplasty: A Systematic Review and Meta‐Analysis

ABSTRACT Background and Aims Standard protocols for the direct anterior approach (DAA) typically employ a longitudinal incision, which violates Langer's lines and may compromise scar esthetics. The oblique “bikini” incision aims to improve cosmesis by following natural skin tension lines, but it raises anatomical concerns regarding iatrogenic lateral femoral cutaneous nerve (LFCN) injury. This study aimed to systematically evaluate the safety, functional, and esthetic outcomes of the bikini incision versus the traditional longitudinal incision in DAA total hip arthroplasty (THA). Methods Adhering to the PRISMA 2020 guidelines, we searched major databases for comparative studies (both randomized controlled trials (RCTs) and observational cohorts) of bikini versus longitudinal incisions in DAA‐THA. Primary outcomes were scar cosmesis and LFCN injury incidence. Secondary outcomes included operative time and wound complications. Data were pooled using a random‐effects model, and subgroup analyses were performed to explore heterogeneity based on study design. Results Eight studies comprising 2017 hips were included. The bikini incision demonstrated significantly superior scar cosmesis (SMD = −0.62; 95% CI [−1.00, −0.24]; p = 0.001) without increasing operative time (MD = −0.52 min; 95% CI [−2.62, 1.58]; p = 0.63). The pooled analysis showed no significant difference in overall LFCN injury risk (OR = 1.19; 95% CI [0.60, 2.36]; p = 0.61); however, subgroup analysis of high‐quality RCTs indicated a higher risk in the bikini group (OR = 2.15; 95% CI [1.26, 3.68]; p = 0.005). Additionally, the bikini group exhibited a potential trend toward reduced wound complications, though this did not reach statistical significance (OR = 0.42; 95% CI [0.15, 1.15]; p = 0.09). Conclusion The bikini incision offers superior scar esthetics without prolonging operative time and demonstrates a potential trend toward minimizing wound complications. However, surgeons must remain vigilant regarding LFCN anatomy, as rigorous RCTs suggest a higher anatomical risk of nerve injury. This approach is recommended primarily for experienced surgeons who have surpassed the standard DAA learning curve.