Most of the early knee joints were uniaxial, and the main characteristics were simple structure, easy to manufacture, and low cost. Low safety performance, so this joint is gradually replaced by multiaxial knee joints.
In contrast to uniaxial knee joints, multiaxial knee joints are stable during the support period and are prone to transition to the swing phase. The multiaxial knee joint allows the patient to remain stable when heeling the ground, and when walking, the stump only needs to use less force to flex the joint. According to the characteristics, the multi-axis knee joint can be divided into hydraulic control, pneumatic pressure control, and automatic locking.
 
Next, let's briefly talk about the characteristics of the branches of the multiaxial knee joint.  
Hydraulic control of the knee joint is the use of hydraulic oil characteristics, by adjusting the oil path to achieve control of piston movement, which can make the walking gait become more ideal. However, the hydraulic device will have an impact on the response speed of the knee joint, for example, when the patient wants to speed up the walking speed, when the thigh is forced, the flexion resistance generated by the knee joint will increase due to the increase in the buckling speed and the increase in the speed of the reverse movement of the oil in the oil path, thereby limiting the flexion of the knee joint. Hydraulic oil will become viscous at low temperatures, resulting in increased swing resistance of the joints, which requires more force when used. The working principle of controlling the knee joint with pneumatic control is basically the same as that of the hydraulic control of the knee joint. The main difference is that when adjusting gait, the pneumatic control knee joint does not limit the knee flexion too much, and the pneumatic control device reduces the weight of the product and also reduces the failure rate. The auto-locking knee joint locks automatically at the end of the swing period or when it is fully straightened, and the joint lock can be automatically released after the end of the support period. The auto-locking knee joint has the characteristics of support period locking, and free knee flexion during the swing period. First of all, under the guidance of medical staff, it is necessary to master the care of the stump, maintain the hygiene of the stump and prevent complications. Secondly, it is necessary to pay attention to maintaining a good position, and under the guidance of prosthetic professional and technical personnel, carry out training to enhance muscle strength and strengthen the range of motion of the joints to prevent joint contractures and deformities of the stump limbs. And as early as possible to prepare temporary prosthesis, so that can speed up the stump atrophy stereotype, early exercise can reduce complications, help improve the general physical and mental condition of amputees, and lay the foundation for a permanent prosthesis to obtain a satisfactory gait as soon as possible.