Ultrasound-Guided Injection Therapy of Achilles Tendinopathy With Platelet-Rich Plasma or Saline: A Randomized, Blinded, Placebo-Controlled Trial

Background: Achilles tendinopathy (AT) is a common and difficult to treat musculoskeletal disorder. Purpose: To examine whether 1 injection of platelet-rich plasma (PRP) would improve outcomes more effectively than placebo (saline) after 3 months in patients with AT. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 24 patients with chronic AT (median disease duration, 33 months) were randomized (1:1) to receive either a blinded injection of PRP (n = 12) or saline (n = 12). The primary endpoint was improvement in Victorian Institute of Sports Assessment-Achilles (VISA-A) score at 3 months. Secondary outcomes were pain at rest, pain while walking, pain when tendon was squeezed, ultrasonographic changes in tendon thickness, and color Doppler activity. Patients were informed that they could drop out after 3 months if they were dissatisfied with the treatment. Results: After 3 months, all 24 patients were reassessed (no dropouts). No difference between the PRP and the saline group could be observed with regard to the primary outcome (VISA-A score: mean difference [MD], -1.3; 95% CI, -17.8 to 15.2; P = .868). Secondary outcomes were pain at rest (MD, 1.6; 95% CI, -0.5 to 3.7; P = .137), pain while walking (MD, 0.8; 95% CI, -1.8 to 3.3; P = .544), pain when tendon was squeezed (MD, 0.3; 95% CI, -0.2 to 0.9; P = .208), color Doppler activity (MD, 0.3; 95% CI, -0.2 to 0.8; P = .260), and tendon thickness (MD, 0.8 mm; 95% CI, 0.1 to 1.6 mm; P = .030). After the 3-month follow-up, a large dropout was observed: 75% of patients in the PRP group and 33% in the saline group. Conclusion: PRP injection did not result in an improved VISA-A score over a 3-month period in patients with chronic AT compared with placebo. The only secondary outcome demonstrating a statistically significant difference between the groups was change in tendon thickness; this difference indicates that a PRP injection could increase tendon thickness compared with saline injection. The conclusions are limited to the 3 months after treatment owing to the large dropout rate.