Which condition might result in lateral trunk bending in transtibial (TF) prosthetics?

Lateral trunk bending in transtibial prosthetics often occurs when the prosthesis is too short. A short prosthesis can disrupt the body’s natural alignment and mechanics during gait, leading the user to lean toward the sound limb to compensate for the lack of length on the prosthetic side. This compensatory mechanism helps maintain balance and stability but results in a lateral deviation of the trunk.

When the prosthesis is appropriately sized, the user can walk with a more aligned posture, minimizing unnecessary lateral movements. In contrast, other options, such as a socket that is too tight, may lead to discomfort or pain but not necessarily a change in trunk alignment. Similarly, excessive dorsiflexion of the foot or an overly firm suspension system could contribute to other gait abnormalities but are less likely to cause the specific behavior of lateral trunk bending. The alignment and length of the prosthetic limb are critical factors influencing overall gait mechanics, making the length of the prosthesis a key determinant in preventing lateral trunk bending.