Clinical Outcomes of Biologic Treatment for Chronic Tendinopathy

Abstract

Biological interventions, such as ultrasound-guided platelet-rich plasma (PRP) injections, are a second-line treatment worth considering for recalcitrant tendinopathy, but efficacy and effectiveness have not been established yet. The use of PRP has been most commonly studied in lateral epicondylitis, with 9 randomized controlled trials and 7 prospective controlled studies in the medical literature. Corticosteroid injection was used as the comparator in 6 studies, autologous blood in 3, and local anesthetic agents in 2 studies. Recent meta-analyses showed that the PRP and autologous blood are superior to corticosteroids in pain reduction and ameliorating functionality in epicondylitis. PRP efficacy on supraspinatus tears is controversial, and PRP is better than controls in 2of 5 studies, when compared with corticosteroids and dry needling. Patellar tendinopathy is examined in 4 controlled studies and 8 case series, with PRP ameliorated outcomes but not in all cases. Whether more than 1 injection should be given is under discussion. Achilles tendinopathy was examined in 3 prospective controlled studies (a single injection) and 6 case series. Patients showed improvements regarding baseline values, but 2 controlled studies failed to reveal differences with controls. Pooling data across studies are challenging because of heterogeneity in outcome scores and comparators. Tendinopathy progression and outcomes are poorly monitored with self-reported questionnaires that are not sensitive enough to discriminate local changes. Molecular indicators of tendon health and disease can help to assess whether the condition progresses or heals after biological interventions. The international consensus about the design of clinical studies should be pursued.