Mid-term Results of Core Decompression Combined With Bone Marrow Aspirate Concentrate (BMAC) Injection for Early Osteonecrosis of the Femoral Head: A Prospective, Pilot Study.

INTRODUCTION: Osteonecrosis of the femoral head (ONFH) is a chronic, debilitating affliction of the hip, with a high incidence in the employable population, thus posing a significant social and economic burden. To date, total hip arthroplasty (THA) remains the only successful treatment for the late stages of ONFH. Various joint-preserving surgical options have been described for early ONFH, with varying success rates. The study aimed to analyze the functional and radiological outcomes of core decompression (CD) combined with bone marrow aspirate concentrate (BMAC) injection for early ONFH. MATERIAL AND METHODS: A total of 30 patients with ONFH, Ficat-Arlet Stage I, IIA, and IIB, underwent CD with BMAC injection under fluoroscopic guidance, followed by a period of protected weight-bearing and physiotherapy. Patients were reviewed at 3, 9, and 15 months to look for improvement in the following parameters: pain on visual analogue scale (VAS), hip range of motion (ROM), weekly analgesic requirement, Harris Hip Score (HHS), and reduction in size of lesion on magnetic resonance imaging (MRI). RESULTS: The mean age of the study population was 41.2 ± 6.74 years. Mean VAS scores and HHS significantly improved over time (Friedman's test, p < 0.001). Median weekly analgesic doses reduced from 14 (interquartile range (IQR): 10-18) preoperatively to 5 (IQR: 3-7) at 3 months, 3 (IQR: 1-5) at 9 months, and 2 (IQR: 0-4) at 15 months. Following the intervention, hip abduction and external rotation improved significantly (Friedman's test, p < 0.01). While MRI analysis showed an initial significant reduction in size of the lesion at 3 months (p < 0.01, r = 0.33), subsequent follow-ups showed a significant increase (p < 0.01 at 9 months, r = 0.35; p < 0.05 at 15 months, r = 0.29), suggesting limited durability of radiological improvement or possible disease progression despite initial response. A Kaplan-Meier survival analysis indicated a 30% progression rate to Stage III.  Conclusion: While CD with BMAC injection has definite advantages in decreasing pain and improving hip ROM, our results suggest that patients with smaller initial lesions and better baseline function may have a more favorable outcome than those with more widespread involvement of the weight-bearing dome. However, MRI findings and a survival analysis indicated a 30% progression rate to Stage III, raising concerns about the long-term efficacy of this treatment.