SR: poor-quality data suggests stem cell joint injections are safe, but of unclear benefit

Reference

McIntyre JA, Jones IA, Han B, Vangsness CT, Jr. Intra-articular mesenchymal stem cell therapy for the human joint: a systematic review. Am J Sports Med 2018;46(14):3550-3563.

Synopsis

These authors conducted a limited systematic review of the literature by searching MEDLINE and the Cochrane Library and the bibliographies of included studies to find studies that evaluated intra-articular injections of mesenchymal stem cells. The included studies were published in English and could be case studies with at least 3 patients. The authors did not search for unpublished studies. Ultimately, they included 28 small studies with an average of 23 participants; half evaluated patients with degenerative joint disease and half evaluated patients with chondral defects. Only 3 were randomized trials: 2 evaluated patients with degenerative joint disease, and one evaluated patients with high-grade cartilaginous knee lesions at arthroscopy. One study used allogenic stem cells, while all others used autologous sources. The study duration ranged from 6 months to 60 months—most lasted 16 months to 24 months. Other than localized pain and swelling at donor and injection sites, only 3 patients in all the studies experienced a serious adverse event: one developed a kidney stone, one developed unstable angina 3 months after the procedure, and one control patient developed a deep vein thrombosis. With the small number of participants, it is likely that infrequent complications would easily be missed. The bulk of the studies evaluated pain, function, and radiographic changes. The authors report that, overall, patients were better after receiving the stem cell injections. However, the data from observational studies are likely to be biased, so conclusions about therapeutic effectiveness are limited.