In a SACH foot alignment for TT prosthetics, how far should the socket be positioned anterior to the ankle bolt?

In the alignment of a SACH (Solid Ankle Cushioned Heel) foot for transtibial (TT) prosthetics, it is crucial to position the socket in relation to the ankle bolt to ensure optimal function and stability. Placing the socket 37mm anterior to the ankle bolt is a standard parameter that supports the alignment needed for proper gait mechanics.

This distance helps to promote a natural gait by accommodating the required knee flexion during activities such as walking. The anterior positioning allows for appropriate weight distribution during the stance phase, aiding in balance and push-off power. It also aligns the socket relative to the foot to minimize energy expenditure and enhance stability.

If the socket is positioned too far forward or backward, it can lead to uncomfortable gait mechanics, instability, or increased difficulty in ambulation. Therefore, adhering to the 37mm guideline is based on biomechanical principles that optimize the function of a SACH foot in a transtibial prosthesis.