Natural history of flexed knee gait in diplegic cerebral palsy evaluated by gait analysis in children who have not had surgery.

Eighteen children with diplegic cerebral palsy and no history of orthopaedic surgery had two gait analyses a mean of 6.3 years apart to analyse the effects of time on their gait. The mean age of the children at first analysis was 7.7 years (range 4.4-13.3 years). The data was analysed as a whole group (18 children) and as two sub-groups of nine children: those with a shorter follow-up (mean 5.0 years) and those with a longer follow-up (mean 7.5 years) between analyses. The following significant bilateral changes were seen in the whole group and longer follow-up sub-group: deterioration in the range of knee flexion, mid-stance knee flexion, peak knee extension in stance and hamstring length and an improvement in mean and maximum hip rotation. Temporal data showed no significant changes once normalised. There were no bilateral significant changes in data from children evaluated at a mean of 5 years follow-up. GMFCS scores generally improved over time despite the significant increase in flexed knee gait. There was no significant change in gait deviation index in any group over time. There was an increase in body mass index in 16 children but there was no correlation between this and the degree of mid-stance knee flexion. These findings may have implications for longer term follow-up of children with cerebral palsy into adulthood.