Prosthetic management of coxa vara hips with increased femoral offset: the value of hip resurfacing

Background: Restoration of the femoral offset is critical for joint stability, range of motion, and abductor muscle efficiency in hip arthroplasty, particularly in young patients. Hips characterized by "long-neck coxa vara" (femoral offset >40 mm and neck-shaft angle <125°) present significant reconstructive challenges, as standard non-modular stems often fail to restore anatomy without risking instability, limb length discrepancy, or premature loosening due to increased varus moments.

Objective: This study evaluates the radiographic and clinical efficacy of hip resurfacing arthroplasty (HRA) in reproducing native proximal femoral morphology and restoring function in young, athletic patients with high-offset coxa vara.

Key Points: A prospective study of 45 patients (mean age 46.6 years) with coxa vara and offsets exceeding 40 mm underwent HRA. At a mean 9-year follow-up, the Postel Merle d’Aubigné score improved from 11.1 to 17.7, and the Harris Hip Score increased from 50.3 to 97.5 (p<0.0001). Radiographic analysis showed a non-significant mean offset reduction of 1.6 mm. The mean stem-shaft angle was 131.3°, representing a significant mean valgus gain of 8.7° relative to native anatomy (p<0.0001). No cases of dislocation, revision, or limb length inequality exceeding 5 mm were recorded.

Conclusion: Hip resurfacing arthroplasty effectively restores native biomechanical parameters in complex coxa vara morphologies. By facilitating anatomical reconstruction and allowing for protective valgus positioning without compromising offset, HRA provides a durable alternative to conventional total hip arthroplasty in young, active populations, avoiding the complications associated with modular necks or custom implants.