The Impact of Femoral Anteversion Correction on Clinical Outcomes in Total Hip Arthroplasty for Adult Developmental Dysplasia of the Hip

<b>Background:</b> Total hip arthroplasty (THA) in adult patients with developmental dysplasia of the hip (DDH) presents unique surgical challenges due to altered hip anatomy and biomechanics. One of the most critical factors influencing surgical success is correcting femoral anteversion. This study evaluates the effects of different anteversion corrections (increased, unchanged, and decreased) during THA on clinical outcomes in adult Crowe type 3-4 DDH patients. <b>Methods:</b> A retrospective analysis was conducted on 130 patients who underwent THA with anteversion correction between 2008 and 2017 at a tertiary university hospital. Patients were divided into three groups: Group 1 (increased anteversion), Group 2 (unchanged anteversion), and Group 3 (decreased anteversion). Clinical outcomes were assessed using AOFAS and Lysholm scores, Q-angle measurements, and physical examinations, while radiological evaluations were performed to determine implant stability and complications. <b>Results:</b> Postoperative assessments show that increased anteversion is associated with higher rates of instability, knee dysfunction, and pain. Group 1 had significantly lower AOFAS scores (<i>p</i> < 0.001) and fell due to rotational deformity (25.6%). Group 2 exhibited the best clinical outcomes, with the lowest rates of instability and the highest functional scores. Group 3 had moderate functional improvements but a higher dislocation rate (17.1%) than Group 2. <b>Conclusions:</b> Our findings suggest that excessive changes in femoral anteversion during THA, remarkably increasing it, may negatively impact clinical outcomes by causing instability and pain. Preserving the anteversion angle as much as possible is the most favorable approach for optimizing functional recovery and implant stability. Further large-scale, long-term studies are required to confirm these findings and refine surgical strategies for DDH patients undergoing THA.