Mid-term comparative outcomes of autologous bone-marrow concentration to treat osteonecrosis of the femoral head in standard practice

Purpose: To evaluate mid-term effectiveness of core decompression (CD) followed by injection of bone-marrow concentration (BMC) in osteonecrosis of the femoral head (ONFH) compared with CD alone. Methods: We retrospectively studied 60 hips in 45 patients with ONFH Ficat I-II after a mean follow-up of 45 (range 24-171) months. Group A (19 hips) were treated with CD, and Group B (41 hips) with CD plus autologous BMC. Necrotic lesions were classified according to MRI findings in: (i) the lesion angle; and (ii) the relation of the necrotic area to the weight-bearing portion. Outcomes included clinical changes and radiographic femoral head collapse. Risk factors associated with radiological collapse were evaluated by Cox regression analysis. Results: Postoperative Merle D'Aubigne and Postel hip score was similar in both groups. Femoral head collapse was observed in 10/19 hips in Group A and 22/41 in Group B. At 24 months, the probability of not having a collapse was 56.4% (95% CI, 33.6%-79.1%) for Group A and 57.6% (95% CI, 41.7%-73.4%) for Group B (p = 0.47). The risk of collapse increased in hips with a lesion angle higher than 150 degrees (p<0.02, hazard risk [HR] 4.073) in both groups. Conclusions: With the standard BMC technique performed without monitoring the number of progenitors in the concentrate, we are uncertain to observe a significant decrease in femoral head collapse compared to CD alone. Improved outcomes may require the monitoring of progenitor cells injected into the femoral head, particularly in large lesions.