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Stem cell injections for osteoarthritis of the knee

Whittle SL, Johnston RV, McDonald S, Worthley D, Campbell TM, Cyril S, Bapna T, Zhang J et al.

The Cochrane database of systematic reviews, 2025

1,341 participants · 21 citations

Abstract

Background: Stem cells are specialised precursor cells that can replace aged or damaged cells and thereby maintain healthy tissue function. Stem cell therapy is increasingly used as a treatment for knee osteoarthritis, despite the lack of clarity around the mechanism by which stem cell therapy may slow down disease progression in osteoarthritis, and uncertainty regarding its benefits and harms.

Objectives: To assess the benefits and harms of stem cell injections for people with osteoarthritis of the knee. A secondary objective is to maintain the currency of the evidence, using a living systematic review approach.

Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase on 15 September 2023, unrestricted by date or language of publication. We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for relevant trial protocols and ongoing trials.

Selection criteria: We included randomised controlled trials (RCTs), or trials using quasi-randomised methods of participant allocation, comparing stem cell injection with placebo injection, no treatment or usual care, glucocorticoid injection, other injections, exercise, drug therapy, surgical interventions, and supplements and complementary therapies in people with knee osteoarthritis.

Data collection and analysis: Two review authors selected studies for inclusion, extracted trial characteristics and outcome data, assessed risk of bias…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 1,341 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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