Hip, knee, and ankle kinematics of high range of motion activities of daily living.

Treatment of joint disease that results in limited flexion is often rejected by patients in non-Western cultures whose activities of daily living require a higher range of motion at the hip, knee, or ankle. However, limited information is available about the joint kinematics required for high range of motion activities, such as squatting, kneeling, and sitting cross-legged, making it difficult to design prosthetic implants that will meet the needs of these populations. Therefore, the objective of this work was to generate three-dimensional kinematics at the hip, knee, and ankle joints of Indian subjects while performing activities of daily living. Thirty healthy Indian subjects (average age: 48.2 +/- 7.6 years) were asked to perform six trials of the following activities: squatting, kneeling, and sitting cross-legged. Floating axis angles were calculated at the joints using the kinematic data collected by an electromagnetic motion tracking device with receivers located on the subject's foot, shank, thigh, and sacrum. A mean maximum flexion of 157 degrees +/- 6 degrees at the knee joint was required for squatting with heels up. Mean maximum hip flexion angles reached up to 95 degrees +/- 27 degrees for squatting with heels flat. The high standard deviation associated with this activity underscored the large range in maximum hip flexion angles required by different subjects. Mean ankle range of flexion reached 58 degrees +/- 14 degrees for the sitting cross-legged activity. The ranges of motion required to perform the activities studied are greater than that provided by most currently available joint prostheses, demonstrating the need for high range of motion implant design.