Evidence for the Use of Cell-Based Therapy for the Treatment of Osteonecrosis of the Femoral Head: A Systematic Review of the Literature.

BACKGROUND Cell-therapy has been promoted among the therapeutic arsenal that can aid in bone formation and remodeling, in early stages of osteonecrosis of the femoral head (ONFH). The purpose of this systematic review was to assess the evidence supporting the (1) clinical efficacy; (2) structural modifying effect, as evaluated radiographically; (3) revision rates; and (4) safety of cell-therapy for the treatment of ONFH. METHODS A systematic review was performed including studies with a level-of-evidence of III or higher. A total of 1483 articles were screened. Eleven studies met the criteria for inclusion in this review (level-of-evidence: 6 level-I, 1 level-II, and 4 level-III), including 683 cases of ONFH. RESULTS All 10 studies that reported patient-reported outcomes showed improved outcomes in the cell-therapy groups compared with the control group. Overall, 24.5% (93/380 hips) that received cell-therapy showed radiographic progression compared with 40% (98/245 hips) in the control group. Nine of 10 studies that reported failure rates showed a lower total hip arthroplasty conversion rate in the cell-therapy group 16% (62/380 hips) compared with the control group 21% (52/252 hips). There was a low complication rate (<3%) with no major adverse effects. CONCLUSION Cell-therapies for the treatment of ONFH have been reported to be safe and suggest improved clinical outcomes with lower disease progression rate. However, there was substantial heterogeneity in the included studies, and in the cell-based therapies used. Specific clinical indications and cell-therapy standardization are required because studies varied widely with respect to cell sourcing, cell characterization, adjuvant therapies, and assessment of outcomes.