The purpose of this study was to explore the associations between sagittal plane joint kinematics throughout the gait cycle and passive knee range of motion in the form of maximal knee extension in children with CP.
Retrospective gait data of 48 children with spastic CP (age 4-16; mean age 10+/-3y; 24 bilateral CP (bCP), 24 unilateral CP (uCP)) was included. Data from the most affected leg was included in the analysis with the leg with the least available knee extension considered the most affected leg for the bCP group. If there was no difference between left and right, passive ankle dorsiflexion range of motion was additionally considered to differentiate the most affected leg. Cannonical correlation using statistical parametric mapping was used to associate the clinical values of passive knee extension with the sagittal plane kinematic data of the pelvis, hip, knee and ankle throughout the gait cycle.
The children in the bCP group ranged from GMFCS level I to III (I=12; II=9; 3=1) whereas the children in the uCP group were GMFCS level I (n=19) and II (n=5). For the bCP group, 7/24 children showed reduced passive knee extension (0), for the uCP group this was 8/24. The median knee extension deficit for the total group was -10(n=15). The uCP group showed associations between sagittal plane hip kinematics (hip flexion/extension) and passive knee extension between 30 and 61% of the gait cycle (p=0.018). The bCP group showed associations between sagittal plane knee kinematics (knee flexion/extension) and passive knee extension for the full stance phase (0-64%, p0.001) and late swing phase (87-99%; p=0.03). There were no significant associations at the level of the pelvis and ankle.
Current results highlight the differences between gait patterns in children with unilateral and bilateral CP. Where children with uCP with a clinically reduced passive knee extension showed reduced hip extension in late stance, children with bCP did not show these differences. At the level of the knee, children with uCP did not show a significantly reduced knee extension angle during stance, whereas there was a greatly decreased knee extension angle during stance for the bCP group, even though only a minority of these children presented with a passive knee extension deficit.
These preliminary results imply that the association between anatomical factors such as passive joint range of motion and activities in an upright position such as in walking is more complex than currently assumed and requires further detailed investigation to elucidate the complex interactions between these two factors. Specifically considering that their combination is an important indicator for treatment management strategies aiming to enhance walking ability during interdisciplinary patient care such as muscle lengthening surgeries and passive and active range of motion training.
gait kinematics
joint range of motion
