Minimally invasive surgery using an external circular fixator in the treatment of paralytic equinocavus foot deformity secondary to peripheral nerve lesion

Abstract

Objective: The objective of this study is to evaluate the efficacy of correction of rigid feet with severe equinocavus deformity secondary to peripheral nerve lesion. The treatment consists of minimally invasive surgery by gradual and progressive joint distension using a circular external fixator. Methods: In the period July 1993 to June 2010, seven patients were evaluated, all with complications of peripheral nerve lesion and with severe rigid equinocavus deformity of the foot and ankle. The main complaints were claudication, walking difficulty, and painful calluses under the metatarsal heads. Detailed clinical exam and simple radiographs, performed in the lateral view, with support, were compared before and after treatment to measure and grade the correction of deformity and improvement of symptoms. Results: Using clinical and radiographic criteria, we obtained a result that was considered good in six of the seven feet (86%); and regular in only one (14%). In the lateral radiographic evaluation of the foot and ankle, we found average correction of 9.5cm of the equine deformity and 1.0cm of the cavus deformity. There were no major complications during treatment. Complementary surgeries, including osteotomy of the heel (one foot), panarthrodesis (one foot), and arthrodesis of the hallux interphalangeal joint (one foot) were necessary to correct small residual deformities in three of the seven feet treated (43%). Conclusion: Minimally invasive surgery using a circular external fixator to correct severe and rigid equinocavus deformities of the foot and ankle is an efficient and relatively safe treatment alternative. In cases of symptomatic arthrodesis, this procedure significantly facilitates the execution of complementary arthrodesis, reducing the need for extensive bone resection and its potential complications.