Adipose-derived stem cell injections provide borderline meaningful pain relief in adults with knee degenerative joint disease

Reference

Kim KI, Lee MC, Lee JH, et al. Clinical efficacy and safety of the intra-articular injection of autologous adipose-derived mesenchymal stem cells for knee osteoarthritis: a phase III, randomized, double-blind, placebo-controlled trial. Am J Sports Med 2023;51(9):2243-2253.

Synopsis

These researchers from Korea enrolled adults with radiographically confirmed degenerative joint disease of the knee who had pain levels of at least 50/100 on a visual analog scale (VAS) and impaired function on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The authors report that the minimum clinically important difference (MCID) for these scores are 14 points and 9 points, respectively. They randomized the patients (uncertain if the allocation was concealed) to receive ultrasound-guided injections of autologous adipose-derived stem cells (n = 131) or saline (n = 130) performed by a physician not part of the study. They cultured the stem cells for 3 weeks before injection (a practice currently not allowed in the Unites States). They evaluated changes in the VAS and WOMAC only for the 252 patients who completed the 6-month follow-up. After 6 months, both groups had clinically important improvements in pain, but the net difference — 9.7 points — is less than the MCID. Similarly, both groups’ function scores improved, but the net difference was only 5.4 points. More important, more patients who received stem cell injections had clinically meaningful improvements in pain scores (68.6% vs 53.3%; number needed to treat [NNT] = 7; 95% CI 4 - 32) and in WOMAC scores (73.4% vs 47.6%; NNT = 4; 3 - 8) than did those who received placebo. Slightly more than one-third of the participants in each group experienced adverse events, mainly pain and swelling following the injections.