Prosthetic knee is very important for thigh amputees. Human knee joint motion isquite complicated prosthetic knee type.Prosthetic knee is one of most types in prosthetic joint. Knee joint as the important feature,is the most complex parts amongknee, thigh and hip prostheses.The most basic requirement of prosthetic knee joint is that knee can remain stable in the support phase,it can flex in the swing phase.Various knee joints vary in function.
According to the number of the axis of rotation, knee joint is divided into single-axis and multi-axis knee joint. According to stability control method in the support phase,knee joint is divided into manual lock, load-bearing self-locking , geometric lock knee joint.
According to control method in the support phase, knee joint is divided into the pendulum joint, friction control joint, pneumatic joint, hydraulic joint,microelectronic control joints.
According to the material classification, knee joint is divided into single alloy steel, stainless steel, titanium knee joint.It also has composite material of stainless steel and aluminum as well as carbon and stainless steel. A special prosthetic knee disarticulation joint is designed for a long stump of above-knee and knee disarticulation.
Medi-Rehatek prosthetic knee should ensure the stability of the support, and to provide appropriate knee torque of the swing, swing to achieve a flexible and natural. When the foot when walking off into the swing phase, leg swing movement depends on the thigh and knee torque. The size and pattern of the knee moment and walking speed, road conditions and human parameters. Knee friction torque may be provided by the spring force, pneumatic means, hydraulic means. Friction torque can only be set onceaccording to the condition of amputee who is installing prosthesis.
Gait follow of above knee prosthesis is crucial, if the joint damping can not be changed, the gait speed of prosthesis can’t change as healthy limb does.It will resultin gait difference.Amputees will increase energy consumption and feel a great discomfort. Traditional simple prosthesis uses mechanical damping which can not beadjusted or not automatically change with the pace. so the rotation speed of prosthesis in flexion and extension is different from the rotation speed of healthy limb in the gait swing phase.In the stance phase the stability is guaranteed by self-locking device or manual lock.From 1960s to 1970s, the prosthetic knee started using a hydraulic / pneumatic device as a damping element. The rotation speed can be controlled by the hydraulic or pneumatic cylinder of prosthetic knee so that the amputee can meet the needs of faster or slower pace.
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