Radiographic Evaluation of Idiopathic Clubfeet Undergoing Ponseti Treatment

Abstract

Background: The Ponseti method for treatment of idiopathic clubfeet involves the use of serial casts, percutaneous Achilles tenotomy in most cases, and bracing with an abduction orthosis to prevent relapse. Although Ponseti recommended evaluation of the infant clubfoot strictly by palpation, many orthopaedic surgeons still rely on radiographs for decision-making during treatment. The aim of this study was to document with radiographs the effect of percutaneous Achilles tenotomy as described by Ponseti. Methods: We conducted a study of idiopathic clubfeet treated, at two centers, with the Ponseti method, including percutaneous Achilles tenotomy. Cast treatment was started within three weeks after birth, and radiographs were made before and after the tenotomy. Lateral radiographs with the foot in maximal dorsiflexion at the ankle were made for all patients, and anteroposterior radiographs of the foot were made at one center. The lateral tibiocalcaneal angle, the anteroposterior talocalcaneal angle, and the lateral talocalcaneal angle were measured on the radiographs. Foot dorsiflexion at the ankle was evaluated clinically. The results from both centers were evaluated separately and in combination. Results: Lateral dorsiflexion radiographs that showed the foot and ankle were evaluated for eighty-seven clubfeet, and anteroposterior radiographs that showed the foot were evaluated for sixty-five clubfeet. The mean improvement in the lateral tibiocalcaneal angle after the tenotomy was 16.9°. The mean change in the anteroposterior talocalcaneal angle was 2.1°, and the mean change in the lateral talocalcaneal angle change was 1.4°. The mean increase in clinically measured dorsiflexion after the tenotomy (in sixty-five feet) was 15.1°. Only the lateral tibiocalcaneal angle and dorsiflexion as measured clinically changed significantly after the Achilles tenotomy (p < 0.05). When the results at each center were analyzed separately, they were found to be nearly identical. Conclusions: The increase in the lateral tibiocalcaneal angle after Achilles tenotomy is essentially the same as the increase in ankle dorsiflexion seen on clinical examination. The anteroposterior and lateral talocalcaneal angles are not influenced significantly by the tenotomy. Radiographs confirmed that the additional dorsiflexion obtained from the percutaneous Achilles tenotomy is true dorsiflexion occurring in the ankle and hindfoot and not in the midfoot. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.