The longevity of joint prostheses depends on several factors, such as the quality of the biomaterials or the pathologies and particular problems of each patient, which is why it is difficult to define it. However, in a generic way, we can explain that the durability of a joint prosthesis can be between 15-20 years and in some cases up to 30 years.
What is a joint?
A joint is a special structure of the human body, where two or more bones end and whose gear allows movement. To these we add the final part of the bone of a joint that is covered with a smooth and shiny material called cartilage. This material cushions the forces acting on the underlying bone and allows the joint to move easily and painlessly.
The joint is enclosed in a capsule lined inside by smooth tissue called synovium. This produces a lubricant (synovial fluid) that reduces friction and wear on the joint. In addition, crossing the joints there are muscles and tendons that increase their stability and favor movement.
What is a prosthesis?
It is an artificial joint replacement. We must add, although we have already mentioned it, that it has been one of the greatest advances achieved by orthopedic surgery in this century. The joint effort of engineers and orthopedic surgeons has enabled the development of materials and techniques to make this possible.
Prosthetic replacement, in practice, consists of replacing an injured or osteoarthritic joint with an artificial joint called a prosthesis. The prosthesis will take over the functions of the lost joint.
When are joint prostheses necessary?
Joint replacement is recommended to eliminate pain and disability caused by extensive joint destruction. This may be because the joint surfaces may be damaged by osteoarthritis, a process that causes the joint cartilage to wear away.
Another factor to consider is that the joint can also be damaged by rheumatoid arthritis. In this disease, the synovial membrane produces chemicals that destroy joint cartilage.
When joint destruction is significant, a total joint replacement may be the only way for the patient to return to daily activities.
The diagnosis of osteoarthritis or rheumatoid arthritis includes:
- write down the patient’s symptoms
- perform a physical examination
- Lab tests
- x-rays showing the extent of joint destruction
Once the diagnosis is made, the possibility of placing a prosthesis can be considered, always after non-surgical treatment or other surgical alternatives have failed to eliminate pain and disability.
Let us now see in more detail the procedure of a total hip and knee replacement. Its benefits, its risks, complications and recovery times.
Total hip and knee replacement procedures
The total hip and knee replacement procedure is a surgical technique that is performed with the patient under anesthesia. The surgeon replaces the damaged joint with components made of artificial materials.
- The Hip. The upper end of the femur, which is like a ball, is replaced by a metal ball attached to a stem that is inserted into the bone. A plastic dome is implanted in the spherical cavity of the pelvis that is damaged.
- The Knee. The bony ends of the femur and tibia are replaced by prosthetic components that articulate with each other and with the patella (patella). Which in most cases is also replaced?
The materials used in joint replacements are designed to allow mobility similar to that of the normal joint. Prosthetic components are usually made up of a metallic element that fits exactly into a plastic.
The elements used for this type of prosthetic surgery are the following:
- Various metals – stainless steel, cobalt alloys, chrome and titanium
- The plastic – polyethylene which is extremely durable and resistant to wear
- Fixation – cement is usually used, although there are also non-cemented prostheses, which are anchored directly to the bone.