Analysis of Cell Therapies Used in Clinical Trials for the Treatment of Osteonecrosis of the Femoral Head: A Systematic Review of the Literature

Background Osteonecrosis of the femoral head (ONFH) is associated with regional loss of cells within bone, often resulting in pain and mechanical collapse. Our purpose was to analyze the cell-therapies used in clinical trials for the treatment of ONFH with regard to (1) cell-sources, (2) collection techniques, (3) cell-processing, (4) qualitative and quantitative characterizations, and (5) delivery methods. Methods A systematic review of the current literature on the use of cell therapies for the treatment of ONFH was performed. Studies with a level-of-evidence III or higher were evaluated. A total of 1483 articles were screened. Eleven studies met the criteria to be included in this review. Results Ten studies used bone-marrow, and 1 study used blood as the cell-source. Nine studies used freshly isolated tissue-derived nucleated cells from bone-marrow, mixed bone marrow-derived nucleated cells, 1 study used mixed blood-derived nucleated cells, and 1 study used culture-expanded cells derived from bone marrow aspirate. Cell dose varied from 2-million to 3-billion cells. Qualitative cell characterization of injected cells using surface markers was done by 5 studies using CD34. Two studies assayed the cell-population using a colony-forming-unit assay. Conclusion There is a lack of standardization with respect to the quantitative and qualitative characterization of methods for cell-harvest, cell-processing, and cell-transplantation/delivery. Cell-therapy holds promise as a means of restoring local cell populations that are made deficient because of injury or disease. However, the orthopedic community and patients will benefit greatly by a greater investment in blinded, randomized, controlled trials and clinical effectiveness trials that embrace rigorous standards.