Research on the Performance of the Spastic Calf Muscle of Young Adults With Cerebral Palsy

BACKGROUND: The aim of this study was to find an objective graduation of pes equinus in infantile cerebral palsy, especially with regard to functional aspects, to allow a differentiated choice of the therapeutic options. Very often raises the question of whether a surgical lengthening of the Achilles tendon may let expect a functional improvement. METHODS: For this documentation 17 patients with pes equinus and a diagnosis of spastic cerebral palsy, primarily of the lower limbs, and hemiplegia were examined first clinically and then by a procedure for calculating the functional kinetic parameters from an in-shoe plantar pressure distribution measurement (novel pedar-X system), which is used in many orthopedic practices and clinics as a standard measuring device. Using additional video motion analysis, the flexion in the ankle joint and the ankle joint torque were determined. From this the physical performance of the spastically shortened calf muscle was calculated. The course of the curves of torque and joint performance allows a functional classification of the pes equinus. RESULTS: Approximately three quarters of all pes equinus demonstrated functional activity of the most part of the normal push-off propulsion power. Even the rigid pes equinus was capable of performing push-off propulsion work, provided it converted energy that was absorbed during the heel-strike phase and released it again during the push-off phase. This suggests that the function of paretic ankle joint is better than its kinematics of motion. CONCLUSIONS: A heel strike with a pes equinus triggers via stretching stimuli in the muscle-ligament structure reflex motor functions, thereby causing the typical spastic gait pattern. This remarkable gait pattern is often evaluated as dysfunctional and as absolutely requiring correction. However, an aspect possibly neglected in this instance is the fact that this gait pattern may be efficient for the patient and may in fact be a suitable means allowing for economic locomotion despite the cerebral control deficits. KEYWORDS: Pes equinus; Cerebral palsy; Pedography; Ankle joint performance