Upper Extremity Joint Dynamics During Walker Assisted Gait: A Quantitative Approach Towards Rehabilitative Intervention

Background Many children with spastic diplegic cerebral palsy (CP) use anterior or posterior walkers to aid ambulation. Prolonged use may lead to upper extremity (UE) pathology later in life, including arthritis and joint contractures. Purpose This study analyzes the dynamics (kinematics and kinetics) of the shoulder (glenohumeral), elbow, and wrist joints during anterior and posterior walker use. It also examines the dynamic effects of adjusting handle height and grip rotation. Methods Ten children with CP underwent motion analysis with upper and lower extremity marker sets and six-degree-of-freedom instrumented walker handles, while using both anterior and posterior walkers. One child underwent the same analysis, with added trials for wrist derotation (adjusted axial grip rotation) and wrist plus elbow derotation (adjusted handle height). A validated kinematic and kinetic model was applied to calculate UE joint angles, joint reaction forces (JRFs), and joint reaction moments (JRMs). Results Surprisingly, no statistically significant differences in UE angles, JRFs, or JRMs were observed between anterior and posterior walkers. Wrist derotation, however, decreased the flexion JRM seen at the wrist, and elbow derotation decreased the flexion JRM seen at the elbow. Conclusion Anterior and posterior walkers produce similar UE motion and peak loading values. Wrist and elbow joint derotation alters the dynamic effects experienced by the UEs. UE motion analysis during aided gait can be useful for optimizing UE loading conditions to limit pathology later in life

Analysis and modeling of upper and lower extremity dynamics in children with cerebral palsy using walkers

Cerebral palsy (CP) is a condition characterized by a motor disorder that is usually diagnosed during the early stages of life. It occurs from brain damage and has symptoms including postural instability and abnormal muscle tone. A large number of CP patients have spastic diplegic cerebral palsy (lower extremities (LEs) affected more severely than the upper extremities (UEs)) and many use walkers. Several researchers have studied the effects of walkers on the LE gait of patients. However, to date, no quantitative characterization of UE kinematics in subjects using an assistive device such as a walker existed. To better understand full body gait, both UEs and LEs should be assessed. This dissertation analyzes UE (torso, glenohumeral, elbow, and wrist) and LE (pelvis, hip, knee, and ankle) kinematics during use of anterior and posterior walkers. Subjects were recruited and tested during two motion analysis visits (one with each type of walker). Data were process and analyzed through a validated biomechanical model developed for the dissertation. The method of fitting a Fourier series to the kinematic data was used to characterize motion. The data was fit to the linear model: Yij = [alpha] 0 + [Special characters omitted.] [alpha]l sin(2[pi]il /100) + [beta]l cos(2[pi]il /100) + errorij where Yij represented a specific joint angle with i signifying the data for the i th percentage of a gait cycle and j symbolizing the j th trial. From this model, predicted values at each percentage of the gait cycle were determined for each patient. Overall results showed that posterior walker use produced less anterior torso tilt, torso rotation, and ulnar deviation. The posterior walker also increased shoulder extension and internal rotation, and elbow flexion and internal rotation. With the LEs, posterior walker use caused an increase in pelvic tilt and knee flexion. The eventual goal of this line of inquiry is to be able to provide clinicians with quantitative data to assist in prescribing a particular walker for a particular child, with complete confidence that it is the best possible selection. These findings bring us a major step closer to understanding the overall motion of children with CP, how walkers affect their motion, and how both of these factors affect the comprehensive well-being of the children