The talar body prosthesis

Abstract

Arthrodesis or talectomy for the treatment of avascular necrosis of the talus or a severe crush fracture of the body of the talus often produces a disability of the ankle and the foot. Therefore, a prosthesis designed to replace the body of the talus and to preserve the function of the ankle and the foot was developed. The prosthesis has a superior curved surface, and the medial and lateral surfaces are inclined for articulation with the tibia and the fibula. The inferior aspect has a concave curved surface at the posterior aspect of the prosthesis to serve as the posterior facet for articulation with the posterior facet of the calcaneus, and there is a convex curved surface at the anterior aspect of the prosthesis for articulation with the middle facet of the calcaneus. The neck and the head of the talus are preserved to allow insertion of the prosthetic stem into bone. A transmedial malleolar approach is used for insertion of the prosthesis. We inserted the talar body prosthesis in sixteen patients - twelve who had avascular necrosis of the talar body and four who had a severe crush fracture of the talar body - between 1974 and 1990. Three patients who were evaluated five years postoperatively had a satisfactory result, and one patient had failure of the prosthesis at eight months because the diameter of the inferior concave curved surface was too small in the region of the posterior facet and had caused erosion of the posterior facet of the calcaneus. All three patients who were evaluated six to ten years post-operatively had a satisfactory result. All except one of the nine patients who were evaluated eleven to fifteen years postoperatively had a satisfactory result; the exceptional patient had an unsatisfactory result because the prosthetic stem had sunk into the talar neck. This patient had a revision thirteen years after the index operation. We believe that the talar body prosthesis can be used to replace the body of a talus with avascular necrosis or a severe crush fracture, thus maintaining the function of the ankle and the foot for a prolonged period.