Introduction Chronic Achilles tendinopathy (AT) is a common and disabling injury. Injection therapy is often offered if conservative treatment fails, but only sparse scientific evidence exists for injection treatments. High volume injections have shown efficacy in case series [e.g. Chan, 2008]. Evidence for blood product injections is conflicting but they are commonly used in clinical practice [de Vos, 2010]. The aim of the study was to compare the effect of high volume injection (HVI) or platelet rich plasma (PRP) in combination with eccentric training to placebo treatment (sham injections and eccentric training).

Methods Healthy males (21–59 years; n = 55) with AT were randomly assigned to either 1) HVI (50 mls;10 mls 0.5% bupivacaine hydrochloride and 20 mg of Depomedrol followed by 40 mls saline), 2) PRP (~ 4 mls) or 3) placebo treatment. Participants were treated on 4 successive occasions with 2 weeks interval (HVI was only performed once at baseline, the 3 following injections were placebo). The injections were done under ultrasound guidance. All subjects underwent a 12-week eccentric training program. Clinical effects were assessed as changes in symptoms and pain (VISA-A and VAS score), tendon ultrasound thickness and muscle function (one-legged heel-rise test). All outcome measures were recorded at baseline and again at 6, 12 and 24-weeks follow-up.

Results VISA-A scores improved in all groups at each outcome time (p < 0.05). Improvement in VISA-A was significantly greater (p < 0.01) in the HVI (29 ± 4 points) versus PRP (15 ± 3) and placebo (11 ± 3) groups at 12-weeks follow-up. At 24-weeks VISA-A improved was significantly greater in both the HVI (22 ± 5) and PRP (20 ± 5) compared with placebo group (9 ± 3). VAS scores improved in all groups at each outcome time (p < 0.05). Decrease in VAS was significantly greater in the HVI (12 weeks = 45 ± 6 mm; 24 weeks=34 ± 6 mm) and PRP (12 weeks=41 ± 7 mm; 24 weeks = 37 ± 6 mm) compared with placebo group (12 weeks=30 ± 5 mm; 24 weeks=18 ± 6 mm) at 12-weeks and 24-weeks. Tendon thickness only showed a significant decrease (p < 0.05) in HVI and PRP. At 12-weeks the decrease in thickness was larger in HVI (2 ± 0.3 mm) vs PRP (0.8 ± 0.2 mm) and placebo (0.4 ± 0.2) (p < 0.01). At 24-weeks a larger decrease was found (p < 0.05) in HVI (1 ± 0.3 mm) and PRP (1 ± 0.1 mm) vs placebo (0.4 ± 0.2 mm). Muscle function improved in the entire cohort (p < 0.001) with no group interaction observed.

Discussion Treatment with HVI or PRP in combination with a 12-week eccentric training regime in Achilles tendinopathy seems more effective in reducing pain symptoms, improving activity level and reducing tendon thickness than eccentric training alone. HVI was found to be more effective than PRP in the short-term (12 weeks).

References Chan, O, et al . Disabil Rehabil. 2008;30:1697–1708.

de Vos, RJ, et al . JAMA. 2010;303:144–49