Injectable agents derived from or targeting vascularity: has clinical acceptance in managing tendon disorders superseded scientific evidence?

OBJECTIVES To report outcomes after sclerosing, platelet-rich plasma (PRP) and autologous blood injection therapies as a treatment for tendinopathy. METHODS We searched Pubmed for clinical trials on sclerosing, PRP and autologous blood injections for tendinopathy. We scored the quality of the studies using a modified Coleman Methodological Score (CMS) with 9 criteria, which results in a final score between 0 and 90. RESULTS We included 14 studies involving 328 tendons on sclerosing (mean CMS: 52; range 31-77), 6 studies involving 143 tendons on PRP (CMS: 57; 43-73) and 5 studies involving 160 tendons on autologous blood injections (CMS: 58, 50-68). Across treatments, the results appear promising, but as reflected by the low methodology scores, the majority of studies are non-randomized, retrospective, with small sample size or of short duration. Two of three RTCs on sclerosing injections reported better outcomes in the treatment group, while two RCTs on PRP injections show conflicting results. The only available RTC on autologous blood injections has only 8 weeks follow-up. CONCLUSIONS There is a need for large-scale RTCs with appropriate follow-up and study size to determine the efficacy of sclerosing, platelet-rich plasma and autologous blood injection therapies as a treatment for tendinopathy.