Coordination between shoulders and pelvis during walking on sloped and cross-sloped surfaces in unilateral transtibial amputees

Abstract

Numerous studies have explored various kinematics, kinetics and spatiotemporal data in gait analysis of able-bodied subjects and amputees on slope and cross-slope. None have evaluated amputees’ shoulders-pelvis dissociation in these situations. It is important for health professionals to understand how these patients’ shoulder and pelvic girdles move and interact in theses situations to optimize their rehabilitation. The aim of this study is to compare shoulder girdle and pelvis forward progression and their dissociation in transtibial amputees as well as able-bodied subjects during slope and cross-slope conditions. Twenty transtibial amputees and 30 able-bodied subjects walked at self-selected paces uphill and downhill on a 12% slope incline and on a 10% cross-slope incline, in an eight-camera optoelectronic motion analysis system. Measurements included: distance between acromions; distance between anteriosuperior iliac spines according to the x-plane; and angle between the right acromion, left acromion, right anteriosuperior iliac spine and left anteriosuperior iliac spine according to the z-plane. These values were correlated with the gait cycle and compared between groups. Shoulder anterior displacements were significantly greater in the amputee population in every situation, except for downhill left shoulder maximal forward progression. In ascent, their timing of shoulder and pelvis forward progression was significantly altered when compared to able-bodied subjects. Amputees tended to delay their pelvis forward progression, which was quickly followed by their shoulder progression. Their shoulders-pelvis coordination was in-phase instead of being out-of-phase in this condition. During unstable situations, such as downhill and cross-slope, they tended to brake the movement by moving the shoulder after the pelvis, similar to able-bodied subjects. During downhill, amputees’ shoulder girdle and pelvis dissociation angles were significantly less than the control group. Transtibial amputees, like able-bodied subjects, react differently depending on the surface they walk on. Due to the lack of adaptability of the prosthetic foot and the lesser muscular strength of the residual limb, transtibial amputees’ balance on difficult surfaces depends greatly on their shoulder girdle and its coordination with the pelvis. Therefore, sidewalks with slopes or cross-slopes may impede gait and increase risk of fall. As such, these conditions are important to address in rehabilitation.