AbstractThis thesis applied the imaging technology of shear wave elastography (SWE) to the Achilles tendon (AT) and monitoring of a rehabilitation protocol for Achilles tendinopathy (ATY). Study one assessed the reproducibility of SWE, demonstrating coefficient of variations between 2.9% - 6.3%, medium correlations between measures (r = 0.4-0.7), good to excellent Intra-class correlation coefficients (ICC = 0.54-0.85) and interclass correlations of ICC = 0.70 for transverse and ICC = 0.80 for longitudinal scans. Longitudinal scans and keeping the foot relaxed resulted in the least variable results. The second and third studies demonstrated that leg dominance, time of day or previous daily exercise do not impact interpretation of SWE measures, however a 30 minute acute bout of running significantly increased AT stiffness by almost 3%. Interpreting SWE results in the AT immediately following weight bearing exercise may not provide suitable baseline measures for assessment purposes.
The fourth study demonstrated that patients with symptomatic ATY had significantly lower AT stiffness (10%) compared to asymptomatic controls. A 12 week EcEx programme increased AT stiffness by 7.2% and the difference between pathological and control AT’s at 12 weeks was 3.5%. The 12 week EcEx protocol significantly improved symptom measures, range of motion, muscular endurance and muscular power, with significant decreases in tendon diameter, pain measures and neovascularisation. After the 12 week EcEx programme, despite significant improvements, most measures in the pathological ATs had not reached parity with the controls, leading to the fifth study. This monitored participants post 12 weeks to examine alterations when the EcEx loading was removed and whether continuation of EcExs brought increased benefits. The removal of the EcExs caused regression in the pathological ATs and a decrease in stiffness of 1.8%. Resuming the EcExs resulted in further positive adaptations and after six months, the difference in pathological and control AT stiffness was 1.1% with a discrepancy in symptoms of 4.4%. This is important information for both clinicians and patients and suggests the commonly used programme duration of 12 weeks may need to be increased.
This thesis demonstrates SWE is a reproducible technique with which to assess the mechanical properties of the AT in vivo. SWE may be use easily and effectively to offer clinicians and researchers additional information regarding the internal state of tendons, tendinopathy development and AT stiffness alterations during rehabilitation.
|Date of Award
|Nick Webborn (Supervisor), Peter Watt (Supervisor) & Mara Cercignani (Supervisor)