April 5, 2004

There are many new advances in the field of lower extremity orthotics. Among these, is the development of stance control knee joints in Knee Ankle Foot Orthoses (KAFO). Typically, the stance control knee joint has three settings. One setting is free swing mode, similar to having offset knee joints. Another leaves the knee locked straight much like drop locks. The third setting allows the user to swing the leg through with a knee bent and will lock as weight is applied.

In the past, achieving knee stability during stance meant keeping the knee joint locked in the straight position, usually with the use of drop locks. A very unnatural gait results, requiring extraneous body movements and wasted energy. Stance control orthoses allow the knee to bend as the leg swings through to the next step, but with the added advantage of providing stability on weight bearing, even on a slightly bent knee. As a result, the wearer can walk more efficiently, smoothly and consume less energy, and have the security to safely stand on a bent knee.

There are several examples of these stance control knees. The Horton Stance Control Knee Joint uses a cam lock mechanism and weight bearing to allow the knee to bend and lock. The Fillauer Swing Phase Lock utilizes a pendulum mechanism and knee joint angle to lock and unlock. The Becker Orthopedic UTX, Otto Bock Free Walk both rely on knee and ankle joint angles to lock and unlock. The latest addition to this group, the Becker E- Knee, uses a foot sensor and electromechanically controls the knee joint. The added advantage of the E-Knee is that less hip strength is required to use it effectively.

As great as this technology sounds, it is not for everyone and there are certain criteria that must be met for the stance control orthosis to be successful. This can be determined through a thorough evaluation by a certified clinician.
The orthotists here are certified in the evaluation, fabrication, and fitting of both the Horton Stance Control Knee Joint and the Becker E-Knee.