Thigh prosthetic socket, which socket do you use

"Many friends who have installed prosthetic limbs know that an important factor in evaluating the effect of a prosthetic limb after installation is the closest partner to our residual limb [Prosthetic socket]. The quality of the socket of a prosthetic limb directly reflects the wearing effect of the prosthetic limb and the time of walking with the prosthetic limb. So let's take a look at the types of thigh prosthetic sockets.

Suction socket

 

The bottom of the socket does not contact the stump, and a suction space is left between them, which is closed with a suction valve. The negative pressure generated in the suction space is one of the mechanisms of this type of socket suspension. Under the action of suction negative pressure, blood stays in the stump, which can easily cause congestion and edema in the stump and cause harm to amputees. Since the stump is not in contact with the socket, the contact area between the residual limb and the socket is reduced, and the force borne by the surface of the residual limb is correspondingly reduced, and more force has to be transmitted through the ischium. This method of force transmission can adversely affect the patient's gait while wearing the prosthesis. It can also cause discomfort in the ischium for some patients. The suction-type socket is not conducive to the blood reflux of the residual limb, and is only suitable for patients with poor soft tissue coverage of the stump, or patients whose stump is too sensitive and cannot be touched. In order to improve venous blood return, the suction space at the bottom of the suction socket is sometimes filled with silicone rubber or other soft elastic materials.

Full contact socket

 

All contain the stump, and the stump is in direct contact with the socket. The entire residual limb surface is in contact with the socket, increasing the contact area. The average pressure per unit area decreases (P=F/A), allowing some overloaded skin to be partially unloaded. And the larger the containment area, the greater the load-bearing capacity.

Full contact prevents stump swelling from occurring. Sliding between the stump and socket is reduced, resulting in less skin irritation and injury. When swinging the leg, the femur pumps upward, and blood is sucked into the distal end of the residual limb. During mid-stance, the internal pressure of the residual limb contained by the socket increases, and the blood sucked into the residual limb is pumped out again. Promotes blood circulation in residual limbs.

The full-contact socket has the following advantages: the patient has the feeling of touching the ground; promotes blood circulation at the genital end; avoids skin discoloration and hyperkeratosis; reduces and improves phantom limb pain; and distributes force to the entire residual limb surface to avoid excessive local pressure.

The full contact socket is suitable for all patients with a good residual limb condition. Patients whose residual limbs are diseased and whose stump cannot be contacted are not suitable for full-contact sockets.

Ischia-containing socket

 

The literal translation of CAT/CAM socket is "contour-adducted greater trochanter controlled alignment socket", which is also called "internal and external diameter (M-L) narrow socket". Currently, it is collectively known as IRC socket (Ischial Ramal Containment Socket) internationally. It is currently the most advanced socket production technology in the world. The characteristics of CAT/CAM socket:

① There is no obvious supporting plane for the ischium. The socket contains and supports the ischium from the medial and posterior sides; the stump is in full contact

② The internal and external diameters of the socket are quite narrow, while the anterior and posterior diameters are quite wide, forming a longitudinal oval shape, which effectively avoids compression of the blood vessels and nerves at the femoral triangle:

③ The lateral edge of the socket is higher than the greater trochanter, which keeps the femur in an adducted position and increases the lateral stability of the socket;

④ In addition to using the ischium containment area and the lower part of the lateral greater trochanter for support, the socket also mainly uses soft tissue and femur to bear weight, so that the force is distributed on the entire residual limb surface;

⑤ The point of action of the combined force on the socket approaches the center of the hip joint, making it closer to the natural physiological state. Therefore, this type of socket is more comfortable to wear and easier to control the prosthesis; ⑥ Wearing the socket makes the sitting posture beautiful and comfortable, and it is not easy to wear clothes; One of the purposes of the CAT/CAM load-bearing method is to increase the load-bearing weight of the femur.

Double layer socket

 

Also called double-sided UDS socket. The inner flexible socket is made of flexible thermoplastic material through thermoplastic molding technology, and the outer layer is covered with a hard support frame of PP to form an integrated body. The flexible socket plays a role in containing and suspending the residual limb, and the socket wall also has a certain deformation ability. When the residual limb muscles contract forcefully, the socket gives the muscles a certain amount of space through elastic deformation while maintaining the same volume. Patients have a good "natural" feeling when wearing the prosthesis. The hard and solid outer PP support frame plays the role of bearing force. The flexible socket is more comfortable to wear. The shape of the socket changes when the muscles contract, which can massage the residual limb and promote blood circulation.