[Subtalar arthrodesis-surgical management of the planovalgosity of the foot in infantile cerebral palsy]

Abstract

PURPOSE OF THE STUDY The study evaluated the possibilities of the application of the surgical method of fusion and the mutual comparison of its individual types in the treatment of planovalgus deformity in the foot in spastic patients affected by infantile cerebral palsy. Escalated spasm of eversion muscles of the foot with a simultaneous weakening of tibial muscles resulted in their case in relatively very severe deformities of feet and their poor function. The decision on the type of the chosen arthrodesis (extraarticular talocalcanear or triple subtalar) is based on the bone maturity of the patient and the degree of the possible correction of the deformity. On their own group of patients the authors present their experience in the application of the two types of arthrodesis and point out the necessity of an early treatment of the deformity by a less extensive and more considerate type of extraarticular arthrodesis, in their case with the use of a tricortical pelvic bone graft after Grice-Thomas. MATERIAL At the Orthopaedic Department of the Faculty Hospital Brno-Bohunice we treated in the period of 1992-1999 by arthrodesis 31 patients (49 feet) with the basic diagnosis of the spastic form of infantile cerebral palsy.The group comprises 27 girls and 22 boys. Forty-one feet (84 %) was operated on by the method of extrarticular talocalcanear arthrodesis after Grice with the use of a tricortical pelvic bone graft modification afterThomas.The average age of the patients in this group was at the time of operation 10 years and 8 months. The method of a triple subtalar fusion was used for the operation of 8 feet (16 %) in patients of the average age of 19 years and 9 months at the time of the operation. The combined method with the simultaneous lengthening of the shortened Achilles tendon was used in 21 feet. In 18 feet the lengthening of the Achilles tendon as a separate operation was performed prior to the arthrodesis. Ten Achilles tendons did not require such lengthening. A simultaneous combination of the transposition of the tibialis angerior muscle tendon (the Young technique) with extraarticular arthrodesis was used in 19 feet. Surgical results were evaluated on the basis of x-ray measurable angles, the talocalcanear angle in particular, measured on the lateral radiograph. Of great importance is the monitoring of the change of the movement stereotype and clinical examination with the possibility of photo and video documentation. RESULTS The average follow-up of our group of patients is 4 years and 5 months after operation. The minimum follow-up is 12 months after the operation. Regular clinical and x-ray examinations inform about clinical condition of the deformity (derotation of the heel, condition of the longitudinal arch), walking stereotype and evaluation of the position of the bone graft. The results may be divided into 3 categories. The category of excellent results comprises 25 (61 %) operated on feet from the group of extraarticular arthrodesis and 3 feet (37 %) from the group of triple arthrodesis. The category of satisfactory results included 13 (32 %) operated on feet from the first group and 4 feet (50 %) from the second group and 3 operated on feet (7 %) from the first group and 1 foot (13 %) from the second group fell into the category of unsatisfactory results. The talocalcanear angle had a mean preoperative value of 43,5 degrees (28-54) and its postoperative average value was 27 degrees (20-37). The average correction is 16,5 degrees . DISCUSSION In the discussion the authors compared the Thomas technique of harvesting tricortical bone grafts from the iliac crest with harvesting bone grafts from other locations (tibia, fibula, rib, etc.) The main reasons why the authors prefer this type of bone graft is mainly the solidity of the pelvic bone graft, the possibility to avoid its internal fixation, a quality ingrowth of the bone graft and excellent healing of the harvesting location. They compare their experience with the works of Banwart, Bar ras, Dennyson, Lancaster, McCall. Partio, Pirani and Smetana. CONCLUSIONS Both types of fusion have significantly contributed to the solution of planovalgus deformity of the foot in spastic patients. An early extraarticular arthrodesis brings high quality results of the functional condition of the foot. This method can prevent the necessary treatment of a rigid painful planovalgus deformity of the foot in the adult age requiring an extensive operation with the resection of subtalar joints. Both types of arthrodesis increase the stability of planovalgus feet and improve the walking stereotype in general.

Key words: planovalgosity of the foot, cerebral palsy, arthrodesis.