Chronic mid portion achilles tendinopathy is not associated with central sensitisation

Achilles tendinopathy (AT) is a common painful and disabling condition and current understanding of its pathophysiology is incomplete. Widespread hyperalgesia as a clinical manifestation of central sensitisation has emerged as a possible contributor to the pain state in chronic musculoskeletal injuries. Eight AT participants and eight healthy, gender, age and activity matched participants were recruited to participate in a case-controlled repeated measures study. Pressure pain threshold (PPT) was measured with a manual electronic algometer at four sites bilaterally; tibialis anterior (TA), patella tendon (PT), common wrist extensor tendon (CWET), and first dorsal interosseous (1DI). We hypothesised a reduction in PPT scores in the AT group at locations remote to the Achilles tendon compared to the healthy group. A linear mixed model analysis was used to compare the groups with age and gender adjustment. No significant difference was found between groups at any of the locations investigated: TA p= 0.638, PT p= 0.334, CWET p= 0.474, 1DI p= 0.056. Central sensitisation as represented through widespread hyperalgesia was not demonstrated in participants with AT. Our results must be treated with caution given the small number of participants tested. We also expect that the younger average age of our participants combined with a possible predisposition for decreased PPT scores secondary to high training loads may have influenced our results. Further research into pain processing changes with AT patients should be pursued with larger sample sizes and careful attention to participant matching. This will assist in developing the current understanding of pain mechanisms and guide treatment approaches in patients with AT