[Early results of autologous mononuclear bone marrow cell implantation in nontraumatic avascular necrosis of the femoral head].

Objectives: We evaluated early clinical and radiologic results of core decompression combined with autologous mononuclear bone marrow cell implantation for early stage nontraumatic avascular necrosis of the femoral head.

Methods: The study included nine patients (1 female, 8 males, mean age 46.5 years; range 33 to 59 years) with stage I-II nontraumatic avascular necrosis of the femoral head, according to the Steinberg classification. Bone marrow-derived CD34 cells were injected through a core decompression channel into the femoral head. Clinical assessment included a visual analog scale (VAS), Harris hip score, and the WOMAC Osteoarthritis Index. Radiologically, femoral head collapse, narrowing of the coxofemoral joint space, and the size of the osteonecrotic area were assessed. The mean follow-up was 27.2 months (range 24 to 38 months).

Results: Pre- and postoperative (24th month) evaluations showed that the mean VAS score and the WOMAC Osteoarthritis Index decreased from 3.4+/-0.4 to 1.2+/-0.6, and from 33+/-3 to 11+/-6, respectively, with an increase in the Harris hip score (from 54 to 92). Preoperatively, two patients were Steinberg I-B, four were I-C, and three were II-A. Finally, all the patients were stage 0 except for one patient who regressed to I-A. None of the patients exhibited femoral head collapse or narrowing of the coxofemoral joint space.

Conclusion: Autologous mononuclear bone marrow cell implantation relieves articular pain, prevents the progression of osteonecrosis, and hence subchondral fractures. Therefore, it may be treatment of choice particularly in stage I-II avascular necrosis of the femoral head.