A research team assessed the gait patterns associated with two types of mechanical stance control prosthetic knee joints—a weight-activated braking knee and an automatic stance-phase locking knee. They concluded that stance control affects biomechanics primarily in the early and late stance associated with prosthetic limb loading. Unloading and a prolonged swing-phase time for the weight-activated braking knee may be associated with the need for knee unloading to initiate knee flexion during gait.
The researchers obtained spatiotemporal, kinematic, and kinetic parameters via instrumented gait analysis for ten young adults with unilateral transfemoral amputations. Discrete gait parameters were extracted based on their magnitudes and timing.
A 1.01 percent longer swing phase was found for the weight-activated braking knee. The prosthetic ankle push-off also occurred earlier in the gait cycle for the weight-activated braking knee. Anterior pelvic tilt was 3.3 ± 3 degrees greater for the weight-activated braking knee. This range of motion was also higher and associated with greater hip flexion angles.
The study concluded that the differences in pelvic tilt may be related to knee stability and possibly the different knee joint stance control mechanisms.
For more information, see “Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints” in Prosthetics and Orthotics International.
