Patellar and Achilles tendinopathies are predominantly peripheral pain states: a blinded case control study of somatosensory and psychological profiles

Abstract

Study design: Case-control design.

Background: Tendinopathy is characterised by pain on tendon loading. In persistent cases of upper limb tendinopathy, it is frequently associated with central nervous system sensitisation, whereas less commonly linked in the case of persistent lower limb tendinopathies.

Objectives: Compare somatosensory and psychological profiles of participants with persistent patellar (PT) and Achilles tendinopathies (AT) with pain-free controls.

Methods: A comprehensive battery of Quantitative Sensory Testing (QST) was assessed at standardised sites of the affected tendon and remotely (lateral elbow) by a blinded assessor. Participants completed the Victorian Institute of Sports Assessment, a health-related quality of life questionnaire, the Hospital Anxiety and Depression Scale and the Active Australia Questionnaire. Independent t-test and analysis of covariance (sex-adjusted and age-adjusted) were performed to compare groups.

Results: Participants with PT and AT did not exhibit differences from controls for the QST at the remote site, but there were differences at the affected tendon site. Compared with controls, participants with PT displayed significantly lower pressure pain threshold locally at the tendon (p=0.012) and fewer single limb decline squats before pain onset, whereas participants with AT only displayed fewer single heel raises before pain onset, but this pain was of a higher intensity.

Conclusion: PT and AT appear to be predominantly local not widespread pain states related to loading of tendons without significant features of central sensitisation.

Level of evidence: Level 4.

Keywords: athletic injuries; central sensitization; chronic pain; jumper’s knee; pain threshold.