Ultrasound-Driven Evaluation of Achilles Tendon Pathology in Psoriatic Arthritis

  • Aimie Patience

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)

Abstract

Introduction: The Achilles tendon (AT) insertion to the posterior calcaneum is the most common site of enthesitis in individuals with psoriatic arthritis (PsA). The clinical and ultrasound (US) definitions and features of Achilles enthesitis and Achillestendinopathy overlap, yet management strategies differ significantly. Due to the mechanobiology and potential for stress on the entheses to initiate pro-inflammatory pathways, management of AT problems in PsA is complex. There is a lack of guidance regarding the assessment and management of AT pathology in people with PsA. In the absence of evidence for non-pharmacological management, the aim of this study was to address key uncertainties around the assessment of AT pain and pathology in people with PsA which could inform the development of a rehabilitation-focussed trial.
Methods: A series of studies, each addressing an area of AT assessment in PsA or management, were conducted. A systematic review of the prevalence of US features of Achilles enthesitis in PsA was performed. Individuals with PsA, with and without AT pain, and age and sex-matched healthy controls were recruited (33 participants). Between-group differences for the presence of clinical and US features of AT pathology, strain elastography measures, performance-based tests, and patient-reported outcome measures (PROMs) were evaluated in order to identify distinct features in well-defined subgroups and identify possible distinguishing features that could feasibly represent therapeutic targets for intervention. In the absence of validated disease and anatomical-region-specific outcomes measures, measurement properties, feasibility, and acceptability of potential primary and secondary outcome measures for a future trial were evaluated.
Results: A range of manifestations of AT pathology were identified including enthesitis, tendinopathic changes and residual structural changes at both the entheses and mid-portion of the tendon. Following identification of significant heterogeneity in US protocols and scoring systems for the AT, recommendations regarding US evaluation of the AT in PsA were provided. Structural enthesitis US features were found people with PsA, irrespective of the presence of AT pain. Inflammatory US enthesitis features were more prevalent in individuals with PsA and AT pain and Doppler signal was only present in this group. Significant levels of lower limb functional impairment, assessed using the Victorian Institute for Sports Assessment – Achilles (VISA-A) questionnaire and bilateral heel raise test, were identified in individuals with PsA with AT pain. Both PsA groups walked slower and reported higher levels of disability compared to healthy controls. Less than a third of people with AT pain had received treatment from podiatry or physiotherapy services and most reported long-term disabling symptoms. No significant between-group differences were observed in strain elastography measures. The VISA-A questionnaire and the bilateral heel raise test showed good measurement properties, feasibility, and acceptability as candidate primary outcome measures for assessing AT pain and pathology in PsA.
Conclusion: Compared to healthy controls, PsA cohorts exhibited features of AT pathology regardless of the presence of pain, highlighting either subclinical manifestations or residual changes from previous AT involvement. The severity of lower limb functional impairment was significantly greater in the PsA group with AT pain however functional deficits and disability were noted in both PsA groups compared to healthy controls. An unmet need for AT management was identified as individuals with AT pain who are receiving treatment based on current guidelines had persisting, debilitating AT symptoms. Further exploration of the clinical relevance of elastography in PsA enthesitis is required. Feasible and acceptable outcome measures with good measurement properties for future research were identified. The comprehensive evaluation of the full length of the ATs in people with PsA is completely novel and the results of this thesis provide incremental advances on current knowledge on the structure, function and assessment of AT pain and pathology in PsA. This work will help inform future research and the development of a future non-pharmacological, rehabilitative trial.
Date of Award2022
Original languageEnglish
Awarding Institution
  • Glasgow Caledonian University
SupervisorGordon Hendry (Supervisor), Martijn Steultjens (Supervisor) & Stefan Siebert (Supervisor)

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