Foot drop after gastrocsoleus lengthening for equinus deformity in children with cerebral palsy.

BACKGROUND

Gastrocsoleus lengthening (GSL) is the most common surgical procedure to treat equinus deformity in ambulant children with cerebral palsy (CP). Foot drop, where the ankle remains in plantarflexion during swing phase, can persist in some children post-operatively. There is currently limited understanding of which children will demonstrate persistent foot drop after GSL.

RESEARCH QUESTION

Which children develop persistent foot drop after GSL surgery for equinus?

METHODS

We conducted a retrospective cohort study on ambulant children with CP who had GSL surgery for fixed equinus deformity. The aims of the study were: to determine the frequency of persistent foot drop post-operatively and to compare outcome parameters from physical examination and three-dimensional gait analysis for children with hemiplegia or diplegia.

RESULTS

One hundred and ten children functioning at GMFCS Levels I/II/III of 28/75/7 met the inclusion criteria for this study. There were 71 boys and mean age was 9.1 years at time of GSL surgery. The overall frequency of persistent foot drop was 25%, with a higher frequency of persistent foot drop in children with hemiplegia (42%) than children with diplegia (19%). There were significant improvements in dorsiflexor strength and in selective motor control in children with diplegia but not in children with hemiplegia. Mean (SD) pre-operative mid-swing ankle dorsiflexion for children with hemiplegia was - 14.0° (9.9°) and improved post-operatively to - 1.6° (5.5°). For children with diplegia, the pre-operative mid-swing ankle dorsiflexion was - 12.1° (12.9°) and improved post-operatively to + 4.2° (6.9°).

SIGNIFICANCE

Foot drop is present following GSL surgery for fixed equinus deformity in a significant number of children with hemiplegia and to a lesser extent in children with diplegia, which may reflect a difference in the central nervous system lesion between these groups. New management approaches are required for this important and unsolved problem.