Katherine A. Konop

A biomechanical analysis of upper extremity kinetics in children with cerebral palsy using anterior and posterior walkers

Upper extremity (UE) joint kinetics during aided ambulation is an area of research that is not well characterized in the current literature. Biped UE joints are not anatomically designed to be weight bearing, therefore it is important to quantify UE kinetics during assisted gait. This will help to better understand the biomechanical implications of UE weight bearing, and enable physicians to prescribe more effective methods for treatment and therapy, perhaps minimizing excessive loads and torques. To address this challenge, an UE model that incorporates both kinematics and kinetics has been developed for use with walkers instrumented with load cells. In this study, the UE joint kinetics are calculated for 10 children with cerebral palsy using both anterior and posterior walkers. Three-dimensional joint reaction forces and moments are fully characterized for the wrist, elbow, and shoulder (glenohumeral) joints for both walker types. Statistical analysis methods are used to quantify the differences in forces or moments between the two walker types. Comparisons showed no significant differences in kinetic joint parameters between walker types. Results from a power analysis of the current data are provided which may be useful for planning longer term clinical studies. If risk factors for UE joint pathology can be identified early, perhaps a change in gait training routine, walker prescription, or walker design could prevent further harm.

Segmental Kinematic Analysis of Planovalgus Feet during Walking in Children with Cerebral Palsy

Pes planovalgus (flatfoot) is a common deformity among children with cerebral palsy. The Milwaukee Foot Model (MFM), a multi-segmental kinematic foot model, which uses radiography to align the underlying bony anatomy with reflective surface markers, was used to evaluate 20 pediatric participants (30feet) with planovalgus secondary to cerebral palsy prior to surgery. Three-dimensional kinematics of the tibia, hindfoot, forefoot, and hallux segments are reported and compared to an age-matched control set of typically-developing children. Most results were consistent with known characteristics of the deformity and showed decreased plantar flexion of the forefoot relative to hindfoot, increased forefoot abduction, and decreased ranges of motion during push-off in the planovalgus group. Interestingly, while forefoot characteristics were uniformly distributed in a common direction in the transverse plane, there was marked variability of forefoot and hindfoot coronal plane and hindfoot transverse plane positioning. The key finding of these data was the radiographic indexing of the MFM was able to show flat feet in cerebral palsy do not always demonstrate more hindfoot eversion than the typically-developing hindfoot. The coronal plane kinematics of the hindfoot show cases planovalgus feet with the hindfoot in inversion, eversion, and neutral. Along with other metrics, the MFM can be a valuable tool for monitoring kinematic deformity, facilitating clinical decision making, and providing a quantitative analysis of surgical effects on the planovalgus foot.