The use of dynamic EMG in predicting the outcome of split posterior tibial tendon transfers in spastic hemiplegia.

The purpose of this study was to assess the outcome of split posterior tibial tendon transfers in patients with spastic cerebral palsy to determine whether the use of preoperative dynamic electromyography was predictive of surgical success. The study is a consecutive case series of 25 children with spastic hemiplegia who underwent unilateral split posterior tibial tendon transfers for varus foot deformities. Three patients were considered failures because of residual varus, which required further surgery. An additional 5 patients had mild residual varus. Preoperative dynamic electromyographic data were evaluated to determine the etiology of postoperative undercorrection. Undercorrection seems to be related to unrecognized anterior tibial muscle overactivity and advanced age at surgery. Overcorrection did not occur. Dropfoot was noted postoperatively in 52% of patients and was related to early cessation of anterior tibial muscle activity in swing. Split posterior tibial tendon transfer is a successful surgery on those patients with increased posterior tibial muscle activity. Undercorrection can be avoided by assessing the activity of the anterior tibial muscle before surgery. These results are expected to assist in surgical decision making for the equinovarus foot in cerebral palsy.