The Efficacy of Platelet-rich Plasma Injection in the Treatment of Patellar Tendinopathy

Background: Patellar tendinopathy is one of the leading causes of tendon related injuries affecting active individuals. Because of the chronic nature of tendinopathy, traditional measures aimed at treating inflammation have not been effective. Platelet-rich plasma (PRP) has gained favor because of the theorized ability to accelerate tissue healing and regeneration. Will the injection of PRP be an effective treatment for patellar tendinopathy? Methods: An exhaustive literature search was performed using Medline, Web of Knowledge, SPORTDiscus, CINAHL, and the NIH clinical trials site using the keywords: platelet-rich plasma and tendinopathy. The selected articles were analyzed for quality using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Results: Four studies were included that met inclusion and exclusion criteria. A randomized control trial with 23 patients treated with PRP showed superior Victorian Institute of Sport Assessment – Patellar questionnaire (VISA-P) score improvements as compared to 23 patients treated with extracorporeal shock wave therapy at 6 and 12 months follow-up. A prospective cohort followed 43 patients and showed stable improvements in VISA-P at 2, 6, and 84 month follow-up. One prospective cohort analyzed 14 patients who had prior injection and/or surgical treatment with 22 patients who had not received any injection or surgical treatment before. Both treatment groups had decreased pain, but the group who had not received prior treatments showed improved VISA-P. Another prospective cohort examined 24 patients at 20 days post injection and 6 months post injection. No significant improvement was seen at 20 days, but VISA-P did improve at the 6 month follow-up. Conclusion: The use of PRP for treating patellar tendinopathy has shown to be effective in these studies by increasing VISA-P. To date, no randomized control trials comparing PRP to saline or dry-needling have been conducted. Thus, future research should focus on identifying proper treatment time, optimal dosage and number of injections, and ideal PRP concentration. Keywords: platelet-rich plasma, injections, patella, tendinopathy, and jumper’s kne