Biomotion community-wearable human activity monitor: total knee replacement and healthy control subjects

Abstract

The arrival of copious and cheap flash memory, as well as micromanufacturing techniques, permitted us to generate a pager-sized whole-body activity and knee range of motion monitor - and record these kinematics continuously at 32 Hz for two days on a single AA battery. Thus, we report here data from a healthy convenience sample of 5 males and 5 females, and 3 women and 7 men who had total knee replacements (TKR) 25plusmn4 mo previously. Prior to our project, TKRs, artificial (transfemoral) limbs, airline seats, and other ergonomic knee-motion based designs were based on simulated motion lab studies. These latter indicated that les105deg knee flexion was sufficient to accommodate most activities; recently, however, TKR manufacturers began supplying "high flexion" knees that permit >150deg knee flexion. Our data show that healthy Caucasian health care workers rarely employ >120deg knee flexion, nor do Caucasians even with high flexion TKRs-even outside the lab environment