National Physical Therapy Examination (NPTE) Practice Exam

What gait compensation would most likely occur in a patient with a firm heel wedge in a transtibial prosthesis?

1. Excessive knee flexion in early stance

2. Insufficient knee flexion in early stance

3. Premature knee flexion in late stance

4. Toe drag during swing phase

The correct answer is: Excessive knee flexion in early stance

In the context of a transtibial prosthesis fitted with a firm heel wedge, the most likely gait compensation is excessive knee flexion in early stance. This occurs because the firm heel wedge raises the heel of the prosthetic foot, effectively altering the ground reaction forces. When the heel is elevated, it can lead to a more acute angle at the knee when the foot makes contact with the ground. As the individual steps down onto the heel, the increased angle may promote a flexed posture at the knee joint, as the body compensates for the altered mechanics. This compensation often occurs as the user attempts to stabilize themselves or prevent the prosthesis from being too far forward, which can lead to instabilities or difficulties in maintaining balance. The choice of excessive knee flexion aligns with the body’s instinct to seek a position that feels more stable, thus making it the most plausible option. Other potential compensations do exist, but they do not fit the specific biomechanical changes induced by a firm heel wedge as closely as the excessive knee flexion does.