Intra-articular allogeneic adipose-derived mesenchymal stromal cell injections for stage III knee osteoarthritis: a double-blind placebo-controlled trial with 60-month follow-up.
Level 2 - randomized trial
Randomized double-blind placebo-controlled trial
PubMed 42049633 · doi:10.1093/stcltm/szag018
What was done
In a single-site, randomized, double-blind, placebo-controlled trial, 29 patients with symptomatic stage III knee osteoarthritis were assigned to receive two ultrasound-guided intra-articular injections two weeks apart of either allogeneic expanded adipose-derived mesenchymal stromal cells (Arm A, mean total dose 69.58 × 10^6 cells, n=21) or equal-volume normal saline (Arm B, n=8). Blinding was maintained for 12 months, after which Arm A was followed through 60 months. Clinical outcomes were measured using normalized Knee Injury and Osteoarthritis Outcome Score and WOMAC index at 6, 12, 24, 36, 48, and 60 months; MRI was evaluated at baseline and 12 months.
What was found
All 29 subjects completed the trial. Adverse events in the treatment group were mild and transient localized pain and swelling. Arm A showed significant improvements in clinical scores compared to baseline at 6, 12, 24, and 36 months (P < .0001) and MRI structural improvement at 12 months (P < .02). Clinical improvements declined steadily after 36 months and neared baseline at 60 months. The abstract did not report absolute numerical outcome values or between-group statistical comparisons.
Why it matters
This study suggests allogeneic stem cell injections provide clinical and structural benefits in advanced knee osteoarthritis that persist for up to 3 years before diminishing. It highlights both the therapeutic window and eventual attenuation of cell-based therapy over extended follow-up.
Limits
The total sample size is very small (n=29) with an unequal allocation (21 vs. 8). Placebo control and blinding ceased after 12 months, rendering outcomes from 24 to 60 months an uncontrolled, unblinded cohort. The abstract provides no between-group comparative effect sizes or raw numerical scores.
Cited by
- contradicts There are no stem cell treatments that have been rigorously tested in controlled, blinded human clinical trials.