The Progression of Crouch Gait in Bilateral Cerebral Palsy

Cerebral palsy (CP) is due to an insult to the developing brain and is the most common cause of motor deficiency in young children and usually leads to muscle spasticity, weakness and joint contracture which have a significant effect on gait. Crouch gait, defined as excessive knee flexion in stance phase, is a prevalent pathological gait patterns associated with CP and is thought to increase the energy cosy of gait and contribute to increased forces on the knee joint. Crouch is therefore often the focus of surgical intervention in CP. This thesis aimed to inform the natural progression of crouch gait in CP in the absence of surgical intervention.

A systematic review of the existing literature highlighted the lack of prospective studies on crouch gait and found that four of the five retrospective studies included in the final analysis reported increased crouch over time while only a single participant case-study demonstrated an overall improvement in knee extension over time and highlighted variation in crouch gait over a number of assessments.

The current study prospectively assessed knee flexion at mid-stance every six months (to a maximum of six assessments) in the absence of surgical intervention in a cohort of child/adolescent participants with bilateral CP (n=50). Clinical examination, assessment of quality of life (QoL) and daily activity were also completed at each assessment. One-year post-operative outcomes in child/adolescent participants who had surgical intervention (n=16) and the progression of crouch gait in adult participants (n=5) were described separately.

The results highlighted significant intra-participant variability in this measure of crouch gait over repeated analyses and this variability was associated with younger age. The mean value of knee flexion at mid-stance did not increase between the first and last analyses 3.34±0.52 years apart despite a significant increase in hamstring tightness. Overall, there did not appear to be an association between crouch gait and QoL or daily activity measures when examined over repeated assessments.

These results suggest that caution is advised in planning intervention based on an increase in knee flexion in stance phase over two analyses only, particularly in younger children, as this may reflect natural variability in this measure. Furthermore, the results highlight that increased hamstring tightness is not associated with increased knee crouch. This suggests that interventions other than hamstring lengthening should be considered to address crouch gait in bilateral CP.