Knee Flexion While Walking Exceeds Knee Flexion Contracture in Children with Spastic Cerebral Palsy.

Flexed knee gait is commonly related to contractures in children with cerebral palsy (CP). Therefore, knee position while walking was compared with passive knee extension and explored with respect to functional mobility. Gait was assessed with 3D motion analysis in 30 children with bilateral spastic CP, Gross Motor Function Classification System (GMFCS) levels I-III, and in 22 typically developing (TD) children. Knee angle at initial contact (KneeAngleIC) was greater than knee flexion in stance (MinKneeFlexSt) in all groups. MinKneeFlexSt exceeded knee contractures at GMFCS levels II and III. Both KneeAngleIC and MinKneeFlexSt were greater at GMFCS II and III than at GMFCS I and the TD group. The excessive knee flexion while walking at GMFCS II and III could not be explained by knee joint contractures. Functional mobility measured with the timed-up-and-go test took longer in children at GMFCS level III compared to the other groups, assumed to be explained by the energy-requiring flexed knee gait and spatial insecurity. Discriminating between passive knee extension at the physical assessment and maximum knee extension while weight bearing may contribute to further understanding of flexed knee gait and its causes in ambulating children with spastic bilateral CP.