What is a potential cause of a medial whip in TF prosthetics?

A medial whip in transtibial (TF) prosthetics typically occurs during the swing phase of gait, where the foot moves laterally instead of straight ahead. The potential cause of this phenomenon relates directly to the alignment and fit of the prosthetic components.

When the socket is too tight, it can restrict movement and create abnormal forces during the gait cycle. Specifically, a tight socket might lead to the residual limb being held in a position that promotes excessive internal rotation of the knee during the swing phase. This internal rotation can cause the foot to whip away from the body, resulting in a medial whip.

In contrast, while factors such as foot malpositioning or an excessive internal rotation of the knee bolt could contribute to gait abnormalities, they would not necessarily be identified as the primary cause of a medial whip. Additionally, a prosthesis that is too short generally affects ground clearance rather than causing a distinct lateral deviation like a medial whip. Therefore, tightness of the socket plays a crucial role in generating this specific gait pattern.