Technical note: validation of a motion analysis system for measuring the relative motion of the intermediate component of a tripolar total hip arthroplasty prosthesis.
Tripolar total hip arthroplasty (THA) prosthesis had been suggested as a method to reduce the occurrence of hip dislocation and microseparation. Precisely measuring the motion of the intermediate component in vitro would provide fundamental knowledge for understanding its mechanism. The present study validates the accuracy and repeatability of a three-dimensional motion analysis system to quantitatively measure the relative motion of the intermediate component of tripolar total hip arthroplasty prostheses. Static and dynamic validations of the system were made by comparing the measurement to that of a potentiometer. Differences between the mean system-calculated angle and the angle measured by the potentiometer were within +/-1 degrees . The mean within-trial variability was less than 1 degrees . The mean slope was 0.9-1.02 for different angular velocities. The dynamic noise was within 1 degrees . The system was then applied to measure the relative motion of an eccentric THA prosthesis. The study shows that this motion analysis system provides an accurate and practical method for measuring the relative motion of the tripolar THA prosthesis in vitro, a necessary first step towards the understanding of its in vivo kinematics.
Chen
Qingshan
Q
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic College of Medicine, 200 First Street, S.W., Rochester, MN 55905, USA.
Lazennec
Jean Yves
JY
Guyen
Olivier
O
Kinbrum
Amy
A
Berry
Daniel J
DJ
An
Kai-Nan
KN
D000465:Algorithms; D019544:Equipment Failure Analysis / Q000379:methods*; D006621:Hip Joint / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D009068:Movement; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity