The long-term clinical and MRI results following eccentric calf muscle training in chronic Achilles tendinosis

Abstract

Purpose To evaluate the long-term results following eccentric calf-muscle training in patients with chronic Achilles tendinopathy. Materials and methods A total of 24 patients with chronic Achilles tendinopathy were included in a study evaluating MRI findings and clinical symptoms before and after 3 months of daily eccentric calf-muscle strength training. Median duration of symptoms was 18 months (range 6- 120). Four of the patients did not perform the prescribed treatment for different reasons and were followed for 14 months. The resulting 20 treated patients completed 4.2- year (range 29-58 months) follow up. Tendon volume was evaluated by using 3D seed growing technique and signal abnormalities were visually semi-quantitatively graded. Level of pain and performance was categorized using a questionnaire completed by the patient. Results In the symptomatic treated patients, median intensity level of pain decreased from moderate/severe at time of inclusion to mild at follow up (p<0.05). Median level of performance increased from severe impairment at time of inclusion to normal at follow up (p<0.05). 12 out of 20 patients had raised intratendinous signal at time of inclusion compared to 2 out of 20 patients at follow up (p<0.001). Mean tendon-volume measured 6.7 cm3 (SD 2.0) at time of inclusion and 6.4 cm3 (SD 2.0) at follow up (p=0.18). The four symptomatic non-treated tendons did not improve regarding pain, performance, intratendinous signal or tendon volume. Conclusion We found decreased pain, improved performance and decreased intratendinous signal both compared to index examination and immediately after the 3 months training regimen in a 4.2-year clinical and MRI follow up, in a group of patients treated with heavy loaded eccentric calf-muscle training for chronic Achilles tendinopathy. The improvements were greater at 4.2-year follow up, despite no further active treatment, than immediately after the treatment. This may indicate a good long-term prognosis for Achilles tendinosis patients.