Kinematic of the hip joint during the gait of normal subjects and osteoarthritic patients

Purpose of the study The study aimed to analyze the spatiotemporal parameters and 5-dimensional pelvic and hip kinematic components during gait in two groups: patients wit h 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 s ubjects. Method Gait analysis was performed using the optoelectronic system VICON(TM) 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 o n pelvis AP radiograph. A preliminary study was performed to measure reliab ility of the data on II patients. Results At the initial stage of osteoarthritis, speed, cadence, stride length and h ip flexion-extension motion appeared as very close to normal data. After th is initial stage, there was a statistical relationship between these parame ters and arthritis functional grading. Pelvis rotation around the vertical axis did not change according to severity of functional grading. The mean v alue 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 i n the male group. There were no significant relationship between radiograph ical thickness of hip cartilage and functional grading of patients or gait parameters. Discussion This study demonstrates that spatiotemporal gait parameters and kinematic d ata appear as quantitative index which could be used in futur studies. It a lso shows that pelvic rotation is greater in pathological group than in nor mal subjects, even in the extreme beginning of the hip osteoarthritis. This particularity can be explained as a very early consequence of the arthriti s or, in the opposite, as risk factor.