Lateral Shear Forces at the Low Back in Persons with Unilateral Transfemoral Amputation during Overground Walking

The prevalence of low back pain (LBP) is considerably higher in persons with lower-extremity amputation (52-71%) compared to the general population (6-33%) [1]. Alterations in gait and movement among persons with lower-extremity amputation have been associated with overall increases in trunk and pelvic motion [2]. Persons with unilateral transfemoral amputation (TFA), specifically, tend to walk with larger lateral bending of the trunk toward the prosthetic side in singlelimb stance [3]. Due to its relatively large mass compared to the whole body, increases in lateral trunk movement can substantially alter ground reaction force generation, thereby altering joint loads throughout the body [4]. As such, altered gait with increased trunk (and pelvic) motion among persons with TFA likely results in spinal loading patterns distinct from able-bodied individuals. Increased or asymmetric spinal loads are an important proximate cause of LBP [5]; repeated exposure to increased and altered spinal loads may therefore contribute, in part, to LBP onset and recurrence in this population. The goal of the present study was to quantify and compare lumbosacral (L5/S1) lateral shear forces in persons with and without unilateral TFA during overground walking.