Split tibialis posterior tendon transfer for correction of spastic equinovarus hindfoot deformity

Equinovarus hindfoot deformity is one of the most common deformities in children with spastic paralysis ; it is usually secondary to cerebral palsy. Split tibialis posterior tendon transfer is performed to balance the flexible spastic varus foot and is preferable to tibialis posterior lengthening, as the muscle does not loose its power and therefore the possibility of a valgus or calcaneovalgus deformity is diminished. We retrospectively evaluated 33 consecutive ambulant patients (38 feet) with flexible spastic varus hindfoot deformity. Twenty-eight presented unilateral and five bilateral involvement. The mean age at operation was 10.8 yrs (range 6-17) and the mean follow-up was 10; yrs (4-14). There were 20 hemiplegic feet, 11 diplegic and 7 quadriplegic. Eighteen feet also presented an equinus position of the hindfoot, requiring Achilles tendon lengthening. The surgical technique applied was similar to the one described by Green et al, with four skin incisions, two on either side of the foot and ankle. The evaluation of the results was carried out using Kling and Kaufer's clinical criteria. Results were graded excellent or good for 34 out of 38 feet (89.5%). Twenty feet were graded excellent, indicating that the children managed to walk with a plantigrade foot without fixed or postural deformity and did not have callosities. Fourteen feet were graded good in children who walked with less than 50,varus, valgus or equinus of the hindfoot and had no callosities. Four were graded poor, with recurrent equinovarus deformity. The feet with poor results presented a residual varus deformity due to intraoperative technical errors.