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

Abstract

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.

Introduction

There have been few reports on the natural progression of gait in diplegic cerebral palsy (DCP) based on gait analysis [1], [2], [3]. Johnson et al. [1] used 3-D gait analysis to compare temporal and kinematic data from 18 children with spastic diplegia (age range 4–14 years), over a mean of 32 months. The children had no surgery in the year preceding the first gait analysis, but nine had had previous surgery. They found a worsening of gait over time, with decreasing stability and a loss of movement at the pelvis, knees and ankles. Bell et al. [2] assessed 28 children with cerebral palsy (age range 5–16 years) with an average of 4.4 years between gait analyses. Of these subjects, 19 were diplegic, seven hemiplegic and two quadriplegic. Unlike Johnson et al.’s study, no child had a history of previous surgery. Bell et al. [2] also concluded that gait function decreased over time, with a deterioration in kinematics, temporal and stride parameters. Gough et al. [3] performed gait analysis on 12 children with diplegia (mean age 10.1 years) with a mean interval between analyses of 14.1 months. None underwent surgery and a significant increase in the minimum hip and knee flexion in stance was found. More recently Gough and Shortland [4] compared the short term outcomes in children for whom surgery had been recommended and for those for whom surgery was not thought to be necessary. There was no change in maximum knee extension in single support a year later in those children for whom surgery was not thought to be necessary.

Diplegic cerebral palsy is often not a static orthopaedic condition and its effects on function can change over time. Gait analysis is usually performed for children to evaluate problems with mobility or for pre-operative planning. Children undergoing gait analysis are, inevitably, a selected group and those with milder involvement may never have a gait study. This may introduce a bias in studies on children that have used gait analysis as an investigation. There is little information on the natural history of mobility, evaluated by gait analysis, in children with DCP. In the aforementioned studies [1], [2], [3], [4] the maximum mean follow-up was 4.4 years and we wished to report our findings in a similar number of children with DCP but followed up for longer (mean 6.3 years).