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

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.