Abstract
The equinovarus hind foot deformity is one of the most common deformities in children with spastic paralysis and is usually secondary to cerebral palsy. Split posterior tibialis tendon transfer is performed to balance the flexible spastic varus foot and is preferable to posterior tibialis lengthening, as the muscle does not loose its power and therefore the possibility of a valgus or calcaneovalgus deformity is diminished. The cohort of the study consisted of 50 children with cerebral palsy who underwent split posterior tibial lengthening to manage spastic equinovarus hind foot deformity. Our inclusion criteria were: ambulatory patients with cerebral palsy, age less than 6 years at the time of the operation, varus deformity of the hind foot during gait, flexible varus hind foot deformity, and the follow-up at least 4 years. We retrospectively evaluated 33 ambulant patients with flexible spastic varus hind foot deformity. Twenty-eight patients presented unilateral and 5 bilateral involvement. The mean age at the time of the operation was 10,8 years (6–17) and the mean follow-up was 10 years (4–14). Eighteen feet presented also equinus hind foot deformity, requiring concomitant Achilles cord lengthening. Clinical evaluation was based on the inspection of the patients while standing and walking, the range of motion of the foot and ankle, callus formation and the foot appearance using the clinical criteria of Kling et al. Anteroposterior and lateral weight-bearing radiographs of the talo-first metatarsal angle were measured. The position of the hind foot was evaluated according to the criteria of Chang et al for the surgical outcome. 20 feet were graded excellent, 14 were graded good and 4 were graded poor. Feet with recurrent equinovarus deformity or overcorrection into valgus or calcaneovalgus deformity were considered as poor results. There were 23 feet presenting concomitant cavus foot component that underwent supplementary operations performed at the same time with the index operation. None of the feet presented mild or severe valgus postoperatively, while 4 feet presented severe varus deformity and underwent calcaneocuboid fusion sixteen and eighteen months after the index operation. On the anteroposterior and lateral weight-bearing radiographs the feet with severe varus had a negative talo-first metatarsal angle (mean −26,8 ± 18,4), those with mild varus had a mean of −14,5 ± 12,2. In feet with the hind foot in neutral position the mean value was 5.0 ± 7.4. The results of the feet in patients with hemiplegic pattern were better and significantly different than the diplegic and quadriplegic ones (p = 0.005). The results in our cases were in general satisfactory as 34 out of 38 feet were graded excellent and good. The feet with poor results presented a residual varus deformity due to intraoperative technical errors.
