What is a likely cause of terminal impact in TF prosthetics?

Terminal impact in transfemoral (TF) prosthetics refers to the abrupt cessation of motion at the knee joint, often resulting in a loud sound or jolt as the knee reaches full extension. This phenomenon typically occurs when a patient forcibly extends the prosthetic limb rather than allowing it to extend smoothly through the gait cycle.

When a patient deliberately or inadvertently forces the prosthesis into extension, it creates a sudden stop, contributing to the terminal impact effect. This can often stem from a lack of control or awareness of the knee's mechanics during ambulation. Additionally, the design of the knee joint and the friction settings can influence how smoothly the knee transitions through its motion, but the act of forceful extension is the most direct cause of the terminal impact sound.

While factors such as knee friction and the strength of extension aids might influence overall gait dynamics, they do not cause the abrupt jolt associated with terminal impact. A slower gait may lead to other gait deviations but is not directly responsible for the impact sound. Thus, the act of forcibly extending the prosthesis is the key factor leading to terminal impact in TF prosthetics.