TOTAL HIP ARTHROPLASTY IN AVASCULAR NECROSIS OF THE HIP: A PROSPECTIVE OBSERVATIONAL STUDY ON FUNCTIONAL AND RADIOLOGICAL OUTCOMES

Background: Avascular necrosis (AVN) of the femoral head is a debilitating condition that leads to progressive joint destruction and functional impairment. Total Hip Replacement (THR) remains the definitive treatment for advanced-stage AVN (Ficat-Arlet III/IV), yet variations in outcomes based on patient demographics, aetiology, and surgical approaches necessitate further investigation. This study evaluates the functional and radiological outcomes of THR in AVN patients over a 26-month duration.

Methods: A prospective observational study was conducted on 50 patients diagnosed with AVN of the hip who underwent THR. Patients were assessed preoperatively and postoperatively at 6 weeks, 3 months, 6 months, and 1 year using Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Visual Analog Scale (VAS) for pain relief. Radiological outcomes, surgical approaches (Southern Moore vs. Hardinge), complications, and range of motion (ROM) improvements were analysed. Statistical significance was determined using paired t-tests, ANOVA, and Kaplan-Meier survival analysis.

Results: Significant functional improvement was observed with HHS increasing by 116.2% at 12 months (p < 0.001) and VAS scores improving by 77.8% (p < 0.001). Post-traumatic AVN patients exhibited superior outcomes (HHS: 92.1) compared to steroid-induced cases (HHS: 89.2). Radiological evaluation confirmed satisfactory implant positioning in all cases, with 92% showing optimal osseointegration and mild radiolucency (<2 mm) in 8%. ROM improved significantly, with internal rotation (+137.5%) and adduction (+111.3%) showing the highest gains. The Southern Moore approach was associated with 2 cases (4%) of neurapraxia (foot drop), while the Hardinge approach had no neurovascular complications. No cases of periprosthetic fractures, deep vein thrombosis (DVT), or implant loosening were recorded.

Conclusions: THR in AVN patients significantly improves function, reduces pain, and restores mobility, with better outcomes in younger patients (<40 years) and post-traumatic AVN cases. The study reinforces the efficacy of fenestrated cemented femoral stems in promoting osseointegration. The Southern Moore approach carries a higher risk of nerve injury, necessitating careful patient selection. Further long-term studies are required to assess implant longevity and the impact of surgical techniques on long-term outcomes.