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

Area of Science:

• Biomedical Engineering
• Pediatric Orthopedics
• Neurology

Background:

• Flexed knee gait is a common characteristic in children with cerebral palsy (CP).
• This gait pattern is often associated with knee joint contractures, affecting mobility.

Purpose of the Study:

• To compare knee position during walking with passive knee extension in children with CP.
• To investigate the relationship between flexed knee gait and functional mobility in children with CP across different Gross Motor Function Classification System (GMFCS) levels.

Main Methods:

• 3D motion analysis was used to assess gait in 30 children with bilateral spastic CP (GMFCS levels I-III) and 22 typically developing (TD) children.
• Knee angle at initial contact (KneeAngleIC) and minimum knee flexion in stance (MinKneeFlexSt) were measured.
• Functional mobility was assessed using the timed-up-and-go test.

Main Results:

• KneeAngleIC was greater than MinKneeFlexSt in all groups.
• MinKneeFlexSt exceeded measured knee contractures in GMFCS levels II and III.
• Both KneeAngleIC and MinKneeFlexSt were significantly greater in GMFCS levels II and III compared to GMFCS I and TD groups.
• Excessive knee flexion in GMFCS II and III was not fully explained by knee contractures.
• Timed-up-and-go test results indicated longer duration for GMFCS level III, linked to energy-demanding gait and spatial insecurity.

Conclusions:

• Flexed knee gait in children with CP, particularly at higher GMFCS levels, may not solely be attributed to knee contractures.
• The observed gait pattern likely contributes to reduced functional mobility and increased energy expenditure.
• Differentiating between passive knee extension and weight-bearing knee extension is crucial for understanding the underlying causes of flexed knee gait in CP.