The effects of surgical lengthening of hamstring muscles in children with cerebral palsy--the consequences of pre-operative muscle length measurement.

Children with cerebral palsy often undergo multiple orthopaedic surgical procedures in a single episode. Evidence of the effectiveness of individual components within the overall package is sparse. The introduction of musculoskeletal modelling in Oswestry has led to a more conservative management approach being taken with hamstring muscles for children walking in a degree of crouch. Muscles which were shown to be of at least normal length at initial contact were not surgically lengthened, as would have been the case previously. A retrospective review of 30 such patients was therefore possible, comparing 15 patients treated before the policy change who had their hamstrings lengthened with 15 treated after who did not. All patients had pre and post operative gait assessments and significant changes were observed for each group separately and for the two groups when compared. The comparison revealed that preserving the hamstrings does tend to reduce, and therefore normalize, the dynamic muscle length. Examination of the two patient groups separately, however, reveals a more complex picture with more global gait improvements seen when the hamstrings were lengthened. No absolute recommendation can be made to inform the clinical management of all children with normal to long hamstring muscles during gait. The final decision of whether to include a hamstring lengthening will need to take into account the characteristics of the individual child.