Abstract
Background: Ankle-foot orthoses (AFO) are frequently recommended to children with CP to improve their functional ambulatory ability, namely to increase walking velocity and stride length, and decrease cadence. Several studies examined the effectiveness of different types of AFOs based on gait analysis. AFOs however, are usually prescribed upon clinical examination alone. Based on our first year experience at the Dana Gait Lab not all AFOs improved function significantly.
Objective: To investigate the effect of prescribed AFOs on gait performance of children with cerebral palsy.
Methods: Twenty-two children with cerebral palsy (aage 5–17 y; gender: 11 males, 11 females, of them: 8 hemiplegic, 11 diplegic, 3 quadriplegic) were referred for full 3D instrumented gait analysis for different purposes. Using the Vicon 612 system they were studied walking both barefoot and with their prescribed AFOs. The two modes were compared in terms of spatio-temporal parameters and ankle-knee kinematics. Statistical analysis included paired t-test, and Pearson correlation coefficient; level of significance was set to .05.
Results: Using the prescribed AFOs, stride length was significantly increased (on average, 9.95±0.11 cm, p=0.000) while no significant changes were found in walking velocity and cadence (p= .111, p= .420, respectively). Split-by diaganosis revealed significant reduction in cadence (12.7 step/min, p=0.034) in the hemiplegic children. There was no significant improvement in the symmetry index of the stride length and step time due to the use of AFOs. Ankle and knee kinematics at initial contact and at loading response revealed non-significant changes. In the hemiplegic group knee flexion increased significantly (p=0.002) while ankle dorsiflexion at initial contact was almost significant (p=0.3).
The consistency of the results within subject and between modes was highly correlated (r=0.858–0.928) and statistically very significant (p< 0.000).
Discussion: In the current study, the only benefits of AFOs were increasing stride length and some improvement in ankle and knee kinematics. Our findings show that the use of an AFO, by itself, does not change dramatically other walking parameters. The high correlation between barefoot and AFO modes suggests that the child’s basic capability is the main factor that affects the gait pattern. Inappropriate AFO may partly be the reason for the non-significant results in this study.
We conclude that AFO’s should be given only after optimization of the child’s physical capabilities. Prescription should be made after careful evaluation using gait analysis whenever possible.
The abstracts were prepared by Ms Orah Naor. Correspondence should be addressed to Israel Orthopaedic Association at PO Box 7845, Haifa 31074, Israel.
