Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Patients With Chronic Midportion Achilles Tendinopathy: A Randomized Clinical Trial

Abstract

Importance: Platelet-rich plasma injections are used as a treatment for chronic midportion Achilles tendinopathy, but evidence for this treatment is limited.

Objective: In adults with midportion Achilles tendinopathy, to assess the effects of a single platelet-rich plasma injection, compared with sham injection, on the outcome of the Victorian Institute of Sport Assessment-Achilles (VISA-A) score (a single composite measure of Achilles tendinopathy severity).

Design, setting, and participants: A participant-blinded, multicenter randomized clinical trial that included 240 people from 24 sites assigned to either a platelet-rich plasma injection or a sham injection between April 2016 and February 2020. Final follow-up was July 2020. Participants were older than 18 years with midportion Achilles tendon pain for more than 3 months as confirmed by ultrasound, magnetic resonance imaging, or both.

Interventions: A single intratendinous platelet-rich plasma injection (n = 121) or a single sham injection (insertion of a subcutaneous dry needle not entering the tendon) (n = 119).

Main outcomes and measures: The primary outcome was the VISA-A score, measured 6 months after treatment allocation. The VISA-A score contains 8 questions that cover 3 domains of pain, function, and activity, analyzed as a composite score (range, 0 [worst symptoms] to 100 [no symptoms]; minimal clinically important difference in score, 12 points). The primary analysis was adjusted for laterality, age, sex, and baseline VISA-A score.

Results: Among 240 patients assigned to a platelet-rich plasma or sham injection (mean age, 52 years; 138 [58%] women), 221 (92%) completed the trial. At 6-month follow-up, mean VISA-A score values in the plasma-rich plasma group vs the sham injection group were 54.4 vs 53.4 (adjusted mean difference, -2.7 [95% CI, -8.8 to 3.3]). The most common adverse events compared between patients in the platelet-rich plasma group vs the sham group were injection site discomfort (97 vs 73 patients), swelling (56 vs 52 patients) and bruising (48 vs 49 patients).

Conclusions and relevance: Among patients with chronic midportion Achilles tendinopathy, treatment with a single injection of intratendinous platelet-rich plasma, compared with insertion of a subcutaneous dry needle, did not reduce Achilles tendon dysfunction at 6 months. These findings do not support the use of this treatment for chronic midportion Achilles tendinopathy.

Trial registration: isrctn.org Identifier: ISRCTN13254422.

Figure 1.. Recruitment, Randomization and Follow-up in the Achilles Tendinopathy Trial

^aReferred patients were screened from orthopedic foot and ankle clinics. ^bIndicates subcutaneous dry needle injection. ^cSwitched to sham injection due to equipment failure with platelet-rich plasma injection.

Figure 2.. VISA-A Scores at Baseline and 6 Months for Each Participant by Group

The baseline Victorian Institute of Sport Assessment-Achilles (VISA-A) scores for individual participants are connected using blue lines for the platelet-rich plasma (PRP) group and orange lines for the sham (subcutaneous dry needle injection) group. Changes from baseline (indicated by the pre label) to 6 months (post label) are represented by the vertical lines with upward lines indicating improvement of Achilles tendinopathy and downward lines indicating deterioration. Box plots show the summary of baseline, 6 months, and changes by group. Boxes from bottom to top show the 25th, 50th, and 75th percentiles; horizontal dashed lines indicate the mean; horizontal solid lines indicate the median; whiskers with caps indicate the range from the lower to upper adjacent values (25th percentile−1.5 × the interquartile range [IQR]; 75th percentile + 1.5 × the IQR).