Gait Deviation Index of Children with Cerebral Palsy with Severe Gait Impairment

The gait deviation index (GDI) is a comprehensive tool derived from three-dimensional gait analysis providing averaged kinematic data from the pelvis, hip, knee, ankle, and foot. It guides clinicians in quantifying intervention efficacy over time by informing gait performance and magnitude of kinematic change in gait pattern. Severity in motor disability is associated with decreased GDI. However, the lack of information on the GDI of children with severe gait impairment characterized by high crouch angle (> 20°) motivated our group to explore GDI at different levels of the gross motor function classification system (GMFCS). Forty-seven ambulatory children (5–18 years) with cerebral palsy (CP) (28 males; 19 females) with a mean crouch angle 20.15° were compared with 45 normally developing healthy children. The GDI of children with CP was 25% lower than that of age-matched healthy children and 13%–27% lower than that of children with less severe crouch angle (2.2°–18.9°) at similar functional levels reported in the literature. Significant linear decline was observed in GDI across GMFCS I (70), GMFCS II (65.42), and GMFCS III (44.6). Out of nine kinematic variables computed to calculate GDI, minimum knee flexion in stance was three times greater (6.9°) among children at GMFCS I and two times greater (16.1° and 37.39°, respectively) among children at GMFCS II and III compared with children at similar GMFCS levels reported in the literature. This is the first study to report GDI of children with CP characterized by greater crouch angle at varying GMFCS levels. The sensitivity of GDI in detecting minimal clinically important differences can guide physicians and health care professionals in monitoring the outcome of surgical and nonsurgical interventions in children with CP.