Changes in gait velocity, mean knee flexion in stance, body mass index, and popliteal angle with age in ambulatory children with cerebral palsy.

BACKGROUND

The purpose of this study was to explore changes in body mass index (BMI), gait velocity, mean knee flexion in stance, and popliteal angle with age in ambulatory children with cerebral palsy.

METHODS

A cross-sectional sample of 188 ambulatory children with cerebral palsy Gross Motor Function Classification System II or III who had a motion analysis evaluation. Subjects had no previous surgical interventions and were between the ages of 4 and 21. Velocity was normalized to limb length, and BMI was converted to age-adjusted percentile scores (BMI-a).

RESULTS

For GMFCS level II children, age and normalized velocity demonstrated a moderate and significant relationship (r = -0.4; P = 0.000). Age explained 20% of the variance in normalized velocity (P = 0.000). Weak but significant relationships were found between mean knee flexion in stance and normalized velocity (r = -0.3; P = 0.000) and popliteal angle and age (r = 0.3; P < 0.002). For GMFCS level III children, the following variables demonstrated a weak but significant association: normalized velocity and BMI-a (r = 0.3; P < 0.006), popliteal angle, and mean knee flexion in stance (r = 0.3; P < 0.022). Age was not associated with velocity, mean knee flexion in stance, BMI-a, or popliteal angle.

CONCLUSIONS

For GMFCS level II children, as age increases, there is a slight decrease in normalized velocity, and with decreasing normalized velocity, there is slightly increased mean knee flexion in stance. For GMFCS level III children, age was not associated with slower velocities, increased mean knee flexion in stance, or increased popliteal angle. Increased BMI-a was not associated with slower gait velocities or increased mean knee flexion in stance. Increasing BMI-a was not associated with increasing age.