Ultrasonographic observation of the healing process in the gap after a Ponseti-type Achilles tenotomy for idiopathic congenital clubfoot at two-year follow-up

BACKGROUND Ponseti management usually requires Achilles tenotomy during the final stage of serial casting. However, we lack a good understanding of the sequential tendon healing process after tenotomy in the Ponseti bracing protocol. The purpose of this study was to clarify the ultrasonographic process of tendon healing in the gap for up to two years after Ponseti-type Achilles tenotomy in patients with clubfeet. METHODS We conducted an ultrasonographic study to clarify the sequential changes in gap healing for up to two years after tenotomy. The subjects were 23 patients with 33 clubfeet. Achilles tenotomy was performed at mean 10.4 (8-16) weeks after birth. Dynamic and static ultrasonography was performed before tenotomy and at 1, 2, 3, 4, 6, 8, and 12 weeks as well as at 4, 6, 12, 18, and 24 months after tenotomy. RESULTS Continuity and gliding were noted within four weeks. The united portion continued to thicken for up to three months after tenotomy. Starting from the fourth month, the healed portion began to lose its thickness, and this process continued into the sixth month. At one year, the thickness of the tendon did not differ much from that of the tendon on the opposing foot. In cases where patients had clubfoot on both feet and underwent simultaneous tenotomies, measurement of the tendons could not be accurately compared. At two years after tenotomy, slight irregularity of the internal structure persisted when compared with the unaffected foot. In addition, clinical and X-ray findings were evaluated simultaneously, and no recurrence was confirmed. CONCLUSIONS To our knowledge, our results are the first to describe the process of gap healing in the tendon after tenotomy up to and beyond two years, as recommended in the Ponseti bracing protocol. Level of evidence IV.