[Kinematics of the healthy and arthritic hip joint during walking. A study of 136 subjects]. / Cinématique de la coxofémorale saine et arthrosique durant la marche. Etude de 136 sujets.

ABSTRACT

PURPOSE OF THE STUDY The study aimed to analyze the spatiotemporal parameters and 3-dimensional pelvic and hip kinematic components during gait in two groups patients with a primitive osteoarthritis of the hip and control normal subjects. MATERIAL: The study included 51 patients, ranged from 42 to 81 years, and 86 normal subjects. METHOD: Gait analysis was performed using the optoelectronic system VICON with 5 cameras in free-speed conditions. Functional grading of the patients was assessed by Lequesne's score. Thickness of the hip cartilage was measured on pelvis AP radiograph. A preliminary study was performed to measure reliability of the data on 11 patients. RESULTS: At the initial stage of osteoarthritis, speed, cadence, stride length and hip flexion-extension motion appeared as very close to normal data. After this initial stage, there was a statistical relationship between these parameters and arthritis functional grading. Pelvis rotation around the vertical axis did not change according to severity of functional grading. The mean value of this component of pelvis motion was 10 degrees in the pathological group, whereas it was 8 degrees in the female normal group, and 7 degrees in the male group. There were no significant relationship between radiographical thickness of hip cartilage and functional grading of patients or gait parameters. DISCUSSION: This study demonstrates that spatiotemporal gait parameters and kinematic data appear as quantitative index which could be used in future studies. It also shows that pelvic rotation is greater in pathological group than in normal subjects, even in the extreme beginning of the hip osteoarthritis. This particularity can be explained as a very early consequence of the arthritis or, in the opposite, as risk factor.