Ultrasound of the Achilles tendon after surgical repair: morphology and function

Ultrasound is a well established method for the examination of the Achilles tendon. The objective of the study was to provide answers to the following questions: What ultrasonographic structural changes are long lasting after surgical repair? How important is ultrasound with regards to the functional evaluation of late results? 60 patients were examined at an average 11 years (2-19) after surgical repair of Achilles tendon rupture. In only four patients sonographic morphology of the tendon was according to the non-injured side. A variety of distinct basic alterations in ultrasound morphology was found: a hypoechogenic ribbon ventrally to the dorsal paratenon (n = 40), spots of hypoechogenic areas in the tendon (n = 18), dishomogeneous hyperechogenicity with preservation (n = 12) or dissolving (n = 22) of its fibrillar components along the longitudinal axis. In most of the cases the paratenon was thickened or could not be differentiated. In the dynamic ultrasound examination gliding mechanism of the achilles tendon was limited in 41 patients. Extensive functional subjective and objective parameters of all patients were evaluated in an Achilles tendon score. The results were rated as excellent (n = 18), good (n = 29), satisfactory (n = 12) and poor (n = 1). There was no statistical correlation between ultrasound morphology and clinical outcome. Therefore, it was concluded that ultrasound examination is able to reveal long-lasting alterations in echogenicity of the tendon but is only of limited value with regards to evaluation of the functional results after surgical repair.