Clinical Question

Are adipose-derived stem cell injections effective in adults with moderate degenerative joint disease of the knee?

Bottom Line

After six months, adults with moderate degenerative joint disease of the knee who received stem cell injections were more likely to experience clinically meaningful improvements in pain and function than those who received saline injections. (Level of Evidence = 1b−)

Synopsis

The researchers from Korea enrolled adults with degenerative joint disease of the knee confirmed on radiography who had pain levels of at least 50 out of 100 on a visual analog scale and impaired function on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The authors reported that the minimum clinically important difference for these scores was 14 points and 9 points, respectively. They randomized patients (uncertain if the allocation was concealed) to receive ultrasound-guided injections of autologous adipose-derived stem cells (n = 131) or saline (n = 130) that were performed by a physician who was not part of the study. They cultured the stem cells for three weeks before injection (a practice currently not allowed in the United States). They evaluated changes in the visual analog scale and WOMAC only for the 252 patients who completed the six-month follow-up. After six months, both groups had clinically important improvements in pain, but the net difference (9.7 points) is less than the minimum clinically important difference. Similarly, both groups' function scores improved, but the net difference was only 5.4 points.

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 to 32) and in WOMAC scores (73.4% vs. 47.6%; NNT = 4; 95% CI, 3 to 8) than those who received placebo. Approximately one-third of the participants in each group experienced adverse events, which were mostly pain and swelling following the injections.

Study design: Randomized controlled trial (double-blinded)

Funding source: Industry

Allocation: Uncertain

Setting: Outpatient (specialty)

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.