What could cause lateral trunk bending to the prosthetic side during midstance?

Lateral trunk bending to the prosthetic side during midstance is a compensatory mechanism that can occur for various reasons, and all of the options listed can contribute to this posture.

When the foot is inset, the base of support narrows, which can make the user feel unstable. To compensate for this perceived instability, the individual may lean toward the prosthetic side during midstance to create a more stable posture. This can result in lateral trunk bending as they shift their weight toward the prosthetic limb.

Residual limb pain is another significant factor. If the individual experiences discomfort or pain in the residual limb, they may alter their center of gravity or the distribution of weight to avoid putting pressure on the painful area. This shift can manifest as lateral bending of the trunk toward the prosthetic side to alleviate stress on the residual limb.

If the prosthesis is too long, it can disrupt the natural biomechanics of gait. A longer prosthesis may require the user to lean toward the prosthetic side to achieve a proper alignment during the stance phase, effectively causing lateral trunk bending as they adjust to maintain balance.

These mechanisms all underscore how various factors can interrelate, leading to the observed compensatory behavior during ambulation. Addressing any of these issues—whether