Blood flow restriction training compared to conventional training in people with knee pain: a systematic review with meta-analysis.

This systematic review and meta-analysis asked whether blood flow restriction training (BFRT), which uses a cuff to partially limit blood flow during low-load exercise, adds any benefit for people with knee conditions when combined with resistance training. The authors pooled 15 randomised controlled trials with 418 participants, covering people after ACL reconstruction or cartilage surgery, and those with knee osteoarthritis or patellofemoral pain. Adding BFRT to resistance training showed a small statistically significant improvement in pain (SMD 0.47) compared to resistance training alone, but this was rated very low certainty evidence and described by the authors as of questionable clinical relevance. For function and quadriceps strength, BFRT plus resistance training performed similarly to resistance training alone, again with very low certainty evidence.

The main limitation is the low quality and small size of the underlying trials, meaning these findings could change substantially with better research.

This review looked at blood flow restriction training (BFRT), a technique using a cuff on the leg to partly limit blood flow during exercise, to see if it helps people with knee problems. Researchers combined results from 15 studies involving 418 people total, including those recovering from ACL surgery or cartilage surgery, and people with knee osteoarthritis or patellofemoral (kneecap) pain. When BFRT was added to regular strength training, there was a small improvement in pain compared to strength training alone, but the researchers rated this evidence as very low certainty and questioned whether the size of the improvement would actually matter to patients.

For muscle function and quadriceps strength, adding BFRT made no real difference compared to strength training on its own. The main limitation is that the studies included were generally small and not high quality, so these results are quite uncertain and could change as better research becomes available. No adverse events were reported.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This meta-analysis pooled 15 RCTs (n=418) across post-ACL reconstruction, cartilage surgery, knee osteoarthritis, and patellofemoral pain populations to evaluate BFRT added to resistance training. The pooled effect for pain favoured BFRT with a small standardised mean difference of 0.47 (95% CI 0.09 to 0.85), but GRADE certainty was rated very low, and the authors themselves flag the magnitude as of questionable clinical relevance. For function and quadriceps strength, BFRT combined with resistance training was statistically equivalent to resistance training alone, also with very low certainty evidence.

The heterogeneous diagnostic populations pooled together, small trial sizes, and low certainty ratings across all outcomes limit confidence in these estimates and any interpretation of clinical utility. The authors note that future high-quality RCTs are needed to properly establish efficacy, and that caution is warranted given the current evidence base. No adverse event data were reported in the abstract.