Platelet-rich plasma = saline for patients with patellar tendinopathy

Reference

Scott A, LaPrade RF, Harmon KG, et al. Platelet-rich plasma for patellar tendinopathy: a randomized controlled trial of leukocyte-rich PRP or leukocyte-poor PRP versus saline. Am J Sports Med 2019;47(7):1654-1661.

Synopsis

In this multicenter (Seattle, Oslo, Bologna) trial, the authors enrolled 61 adults, 18 years to 50 years of age, with at least 6 months of clinically diagnosed patellar tendinopathy confirmed by ultrasound with persistent symptoms in spite of a minimum of 6 weeks of exercise-based rehabilitation. The authors randomized patients to receive ultrasound-guided injections of either leukocyte-rich platelet-rich plasma, leukocyte-poor platelet-rich plasma, or saline. One week later, all patients engaged in a supervised gym-based rehabilitation program 3 times weekly for 6 weeks. Using standardized scales, the researchers evaluated each patient's pain, function, and activity limitations at baseline, and at 12, 24, and 52 weeks after the injections. Additionally, they asked the patients' for their own overall rating of change at the subsequent assessments. They had nearly complete (93%) follow-up at 12 weeks, but only 79% at the end of a year. At no point in the study did the authors find any differences in the 3 groups as to any of the outcomes or patient global assessment of improvement. Six weeks after the intervention, 5 patients, none whom received saline, reported overall worsening compared with their baseline. The authors report one patient experienced localized patellar tendon pain following the injection, enough to prevent activity. No other harms are reported, possibly because of the small sample size. The study was large enough to detect clinically meaningful differences in pain and functional limitations.