Value of quantitative MRI parameters in predicting and evaluating clinical outcome in conservatively treated patients with chronic midportion Achilles tendinopathy: A prospective study

Objectives: To evaluate whether baseline MRI parameters provide prognostic value for clinical outcome, and to study correlation between MRI parameters and clinical outcome. Design: Observational prospective cohort study. Methods: Patients with chronic midportion Achilles tendinopathy were included and performed a 16 week eccentric calf-muscle exercise program. Outcome measurements were the validated Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire and MRI parameters at baseline and after 24 weeks. The following MRI parameters were assessed: tendon volume (Volume), tendon maximum cross-sectional area (CSA), tendon maximum anterior-posterior diameter (AP), and signal intensity (SI). Intra-class correlation coefficients (ICCs) and minimum detectable changes (MDCs) for each parameter were established in a reliability analysis. Results: Twenty-five patients were included and complete follow-up was achieved in 20 patients. The average VISA-A scores increased significantly with 12.3 points (27.6%). The reliability was fair-good for all MRI-parameters with ICCs > 0.50. Average tendon volume and CSA decreased significantly with 0.28 cm(3) (5.2%) and 4.52 mm(2) (4.6%) respectively. Other MRI parameters did not change significantly. None of the baseline MRI parameters were univariately associated with VISA-A change after 24 weeks. MRI SI increase over 24 weeks was positively correlated with the VISA-A score improvement (B = 0.7, R-2 = 0.490, p = 0.02). Conclusions: Tendon volume and CSA decreased significantly after 24 weeks of conservative treatment. As these differences were within the MDC limits, they could be a result of a measurement error. Furthermore, MRI parameters at baseline did not predict the change in symptoms, and therefore have no added value in providing a prognosis in daily clinical practice. (C) 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.