Ultrasonographic findings after Achilles tenotomy during Ponseti treatment for clubfeet: Is ultrasound a reliable tool to assess tendon healing?

INTRODUCTION Several studies have claimed ultrasound to be useful and accurate in assessing the healing phase of Achilles tendons after tenotomy during Ponseti treatment for clubfoot deformity. The purpose of our study was to assess the healing process of Achilles tendons ultrasonographically after tenotomy as part of Ponseti clubfoot management and to assess the effects of previously not considered ultrasound properties (anisotropy, partial volume effect), and whether these practical considerations affect accurate measurements which have been claimed possible in previous studies. MATERIALS AND METHODS We monitored the post-tenotomy healing process in 15 patients (22 tendons) using high frequency ultrasound for a minimum of six months (range 6-14 months). The scanning was discontinued once a tendon looked normal or when the appearance remained unchanged between scans. We also studied nine patients (11 tendons) who had undergone Achilles tenotomies up to seven years previously (range 34-83 months). RESULTS In the immediate postoperative period, ultrasound showed large variations in the distance of the tenotomy from the calcaneum as well as the obliquity and completeness of the surgical division. We encountered pitfalls in the use of ultrasound to define healing stages that were not described previously. Sonography was inaccurate and subjective in assessing both completeness of the surgical division and tendon measurements. Despite ultrasonographically proven incomplete tendon division in 63 % of cases, the clinical effect of an immediate increase of passive foot dorsiflexion from the pretenotomy position with an obvious palpable tendon gap was achieved in all patients. At the end of the study, 65 % of tendons did not achieve a normal appearance. CONCLUSIONS We do not think that routine ultrasound studies are of any value as an adjunct to clinical assessment intra- and post-operatively. It can give misleading information regarding the need to complete the tenotomy, which may increase risks associated with a further pass of the scalpel blade.