Direct Anterior THA with Leg Positioning Traction System for Avascular Necrosis: Technique and Early Outcomes

Avascular necrosis (AVN) of the femoral head commonly affects young adults, particularly in Asian populations, often requiring total hip arthroplasty (THA) at an early age. The direct anterior approach (DAA) is a muscle-sparing technique utilizing the internervous plane between the tensor fasciae latae and sartorius, preserving abductors and posterior structures, and enabling faster recovery with lower dislocation risk. However, DAA is technically demanding and often requires adjuncts, such as leg-positioning traction systems (LPTS) and intraoperative fluoroscopy.

We report a consecutive series of five hips in young patients (mean age 34.6 years) with stage III/IV atraumatic AVN and femoral head collapse. All patients underwent cementless DAA-THA using a mobile LPTS and fluoroscopic guidance. The mean operative time was 85 min, and mean incision length was 11.6 cm. Components were implanted with target acetabular positioning of 40-43° abduction and ~15° anteversion. Full weight-bearing was initiated on postoperative day 1. At a mean follow-up of 14 months, significant functional improvement was observed: Harris Hip Score improved from 41.6 to 91.4, hip disability and osteoarthritis outcome score for joint replacement from 49.8 to 90.6, and Patient-Reported Outcomes Measurement Information System Physical Function T-score from 42.5 to 59.2. Radiographs showed well-aligned components without loosening or subsidence. No dislocations or fractures occurred; one transient lateral femoral cutaneous nerve neuropraxia resolved within 3 months.

Direct anterior approach THA with a leg-positioning traction system and fluoroscopic guidance demonstrated favorable short-term functional and radiological outcomes in this small series of young AVN patients. However, given the limited sample size, retrospective design, and absence of a comparison group, these findings should be interpreted with caution. Larger prospective comparative studies with longer follow-up are required to validate the wider applicability and long-term outcomes of this technique.