Joint Reaction Forces at the Hip Joint during Dynamic Manipulation of the Femur

Objective: To determine if the Articulated Total Body (ATB) Model can realistically model the joint reaction forces generated at the hip joint during posteriorly-directed manipulations of the femur. Methods: A 50th percentile adult male positioned supine with the pelvis constrained, the leg in 0° and 20° of abduction was modeled. Dynamic manipulation forces with a constant period of 0.24 seconds and amplitudes of 250N, 500N, and 750N were applied 10 cm distal to the center of the right hip joint along the longitudinal axis of the right femur in the anterior to posterior direction. Results: The percentage of the applied force seen at the hip joint decreased with increasing load amplitude. Conclusion: This study represents a novel and successful application of the ATB Model to elucidate the time-dependent forces produced within the hip joint during dynamic joint manipulations commonly performed by healthcare practitioners.