Summary of quality and risk of bias of included SRs
| First author | AMSTAR | Risk of bias | Quality rating | Main results and conclusions | Classification of usefulness |
| Andia16 | 6 | High | SR of RCTs, low quality, high risk of bias | One high-quality study with no evidence of effectiveness of PRP; meta-analysis of PRP interventions in tendinopathy cannot inform clinical decision making mainly because of clinical heterogeneity; meta-analysis findings cannot be applied to management of individual patients | Might be clinically useful |
| Balasubramaniam17 | 4 | High | SR of RCTs, low quality, high risk of bias | One high-quality study demonstrating no superiority of PRP for pain or patient satisfaction; given lack of articles, it is difficult to draw any conclusions about the efficacy of PRP, and further research is required prior to widespread clinical use of PRP | Redundant and unnecessary |
| Di Matteo10 | 1 | Very high | SR of case–control or cohort studies, low quality, very high risk of bias | One high-quality study with no evidence of efficacy of PRP, nine case series with evidence of efficacy of PRP; consider PRP an option for management of Achilles tendinopathy; PRP seems useful for tendinopathies not responsive to other conservative treatments so can be considered a second-line approach | Flawed beyond repair |
| Moraes12 | 10 | Very low | SR of RCTs, high quality, very low risk of bias | One high-quality study with no difference in short, medium or long-term functional outcomes between PRP and saline injections; insufficient evidence to recommend the use of PRP for treating musculoskeletal soft tissue injuries or show whether the effects of PRP vary according to the type of injury, or to indicate whether effects of PRP will differ importantly in individual clinical conditions | Decent and clinically useful |
| Taylor18 | 2 | Very high | SR of case–control or cohort studies, low quality, very high risk of bias | One high-quality study with no evidence of efficacy of PRP; one low-quality study showed improvement after treatment with PRP; although preliminary studies have shown promise, RCTs are needed to further confirm the proposed benefits of PRP | Flawed beyond repair |
| Vannini11 | 1 | Very high | SR of case–control or cohort studies, low quality, very high risk of bias | One high-quality study with no evidence of efficacy of PRP; four case series with evidence of benefit of PRP; no clear indication for using PRP in foot and ankle problems (including Achilles tendinopathy) | Flawed beyond repair |
Quality of evidence rating: high quality, very low risk of bias (AMSTAR ≥10); high quality, low risk of bias (AMSTAR 8–9); low quality, high risk of bias (AMSTAR 3–7); low quality, very high risk of bias (AMSTAR ≤2).
AMSTAR, Assessing Methodological Quality of Systematic Reviews; PRP, platelet-rich plasma; RCT, randomised controlled trial; SR, systematic review.