Achilles Tendinopathy Management: Single blinded placebo controlled multicentre randomised clinical trial of platelet rich plasma injections for midportion Achilles tendinopathy

Keywords: Achilles tendon, Injection, Tendinopathy Purpose: Chronic midportion Achilles tendinopathy is common, with an incidence of 2.35 per 1000 people. It is a condition characterised by activity limiting pain and swelling over the midportion of the tendon. There are a wide range of treatment options, of which platelet rich plasma (PRP) injections have grown in popularity. The 2020 global PRP market was $261 million USD and is projected to reach $500 million USD by 2025. The objective of this study was to assess function, quality of life, pain and complications in adults treated with a single platelet rich plasma injection vs. placebo injection for midportion Achilles tendinopathy. Methods: The Achilles Tendinopathy Management (ATM) trial was a single blind multicentre randomised clinical trial registered on the International Standard Randomized Controlled Trial Number registry with reference number ISRCTN 13254422 on 28th October 2015. 24 UK hospital trusts recruited participants 18 years or over, with midportion Achilles tendon pain for longer than three months (tendinopathy confirmed by ultrasound and/or MRI). Exclusion criteria included systemic conditions; pregnancy; prior Achilles tendon surgery or rupture; prior major ankle injury; fracture of a leg long bone in the previous six months; prior platelet rich plasma treatment; or contraindication to receiving a platelet rich plasma. Participants received a single intra-tendinous platelet rich plasma injection (n = 121) or a single placebo injection consisting of a subcutaneous injection of a dry needle (n = 119). The participants were blind to their treatment allocation. Clinicians involved in preparing or delivering the intervention could not be blinded but had no role in collection or assessment of follow up data. The primary outcome was the Victorian Institute of Sport Assessment – Achilles (VISA-A) score six months after randomisation, analysed by Intention-to-treat. Range 0-100, an asymptomatic person would score 100. Secondary outcomes were complications, health related quality of life (EQ-5D-5L; 1 being full health) and pain assessed using a 10 cm visual analogue scale, anchored by two verbal descriptors (no pain and worst imaginable pain). These data were collected at baseline, three and six months after randomisation. Results: 240 participants were randomised, mean age was 52 years (SD 11 years) and 58% were female. At six months 92% (n = 221) completed the study. There was no difference in primary outcome between the platelet rich plasma and placebo injection groups at six-months (Mean difference (platelet rich plasma group – placebo group): −2.7; 95% CI −8.8 to 3.3, adjusted analysis) or in the secondary, imputed or per protocol analyses. There were no differences in the secondary quality of life (EQ-5D-5L utility) or pain (VAS) scores. There were no differences between adverse events for both groups, except for mild discomfort at two weeks (97 in PRP group and 73 in placebo group) and six months (nine in PRP group and one in placebo group). Conclusion(s): We found no evidence that platelet rich plasma injections are an effective treatment for chronic midportion Achilles tendinopathy. Impact: There is no evidence to support continued use of PRP injections in physiotherapy practice for chronic midportion Achilles tendinopathy. Funding acknowledgements: This trial was funded by Versus Arthritis commencing 1st September 2015 (Versus Arthritis 20831). The views expressed are those of the authors and not necessarily those of the funder.