Artificial knee joint
An artificial knee joint can be used to replace a knee that has worn out due to wear and tear. The endoprosthesis ensures that the patient can move pain-free again.
What is an artificial knee joint?
The artificial knee joint is also called knee endoprosthesis, knee joint prosthesis or knee prosthesis. This refers to an implantable endoprosthesis that replaces the human knee either partially or completely. This happens due to pronounced wear of the knee joint or severe knee injuries. Apart from the implantation of a hip joint prosthesis, the insertion of the artificial knee joint is one of the most frequently performed endoprosthesis operations.
In Germany alone, about 150,000 to 175,000 people receive a knee endoprosthesis every year. Most patients have an age of around 70 years. Women receive an artificial knee joint more than men in their lives. The first artificial knee joint was inserted in Berlin as early as 1890. The patients suffering from joint destruction due to tuberculosis were given a simple ivory hinge.
Due to infections, however, the surgical procedures were not successful. Therefore, it was not until 1947 that another implantation attempt was made. From 1951, a model appeared that could also be successfully implanted in larger numbers. From 1968, the first sliding surface replacement prostheses came onto the market. The most common materials today are a cobalt-chromium casting alloy as well as alloys of titanium and surface coatings of titanium nitride or zirconium nitride.
Function, application and objectives
An artificial knee joint is used if there is a permanent dysfunction of the knee and the patient suffers from constant pain and movement restrictions. One of the most common causes of knee problems is osteoarthritis, in which pathological wear of the articular cartilage and soft tissue structures such as the cruciate ligaments or meniscus occurs.In medicine, a distinction is made between primary and secondary gonarthrosis. While there are no noticeable triggers in primary gonarthrosis, the secondary form is caused by sports injuries or accidents. Other reasons for the implantation of an artificial knee joint can be inflammation caused by transported bacteria, rheumatic diseases, malpositions such as X-legs or bow legs, chronic overload due to obesity or injuries.
Typical applications of the artificial knee joint:
- Knee injury
What does the patient have to consider in advance?
Medicine currently uses three different types of prostheses. These are the so-called sled prosthesis, which is a one-sided surface replacement, the complete surface replacement and the complete joint replacement with axis guidance. Each individual type of knee prosthesis has several models. These differ according to the physical activity of the patient, his weight, as well as the shape and size of the knee. The appropriate prosthesis is selected before the procedure by the surgeon, who performs a detailed examination using X-rays. During the operation, he performs trial procedures on the patient’s knee.
The sled prosthesis is used when it is only necessary to replace the inside or outside of the knee because the other areas of the joint are not damaged. The term sled prosthesis is due to the fact that the artificial knee joint moves up and down on a plastic block like a sled. Doctors speak of a complete surface replacement when several knee structures are replaced. If, in addition to the knee joint, ligaments, cartilage structures and bones are also affected, a complete joint replacement with an axle guide is used. However, this type of prosthesis is considered to be very complicated and has the lowest durability.
What does the patient have to consider beforehand and during aftercare?
It is important that any previous illnesses of the patient are known before the artificial knee joint is inserted. The main ones are cardiovascular diseases. In some cases it can be useful if the patient protects his knee before the implantation. It is also necessary to stop taking anticoagulant medication, which is done in consultation with the doctor. After the knee prosthesis implantation, the patient remains in the hospital for about 7 to 14 days. However, the length of stay can vary greatly from person to person. Physiotherapeutic measures begin as early as 24 hours after the operation.
If a cemented artificial knee joint is used in the patient, he may put weight on it at an early stage. However, the opposite is the case with an uncemented prosthesis, since it takes a certain amount of time to heal, meaning that the patient has to take it easy for a long time. In order to train Muscles and joints well, the patient should perform physiotherapy exercises that do not overload the knee. The load capacity of the artificial knee joint depends on the individual healing process. Regular check-ups are carried out to check this.
Execution – How does the investigation work?
In contrast to the implantation of an artificial hip joint, no autologous blood supply has to be created for an artificial knee joint. The blood loss during the procedure is usually very small. Shortly before the operation, the patient is given spinal or general anesthesia. Overall, the procedure can take one to two hours, but this varies from person to person. First, the worn joint surfaces of the knee are removed by the surgeon. He adapts the remaining bones to the knee endoprosthesis.
In some cases, the doctor is supported by special computer-aided navigation systems, which enable the operation to be carried out precisely. To prevent heavy bleeding, the surgeon clamps off the blood vessels. Finally, the artificial knee joint is fixed in the Bone Marrow . With a trial prosthesis, the doctor can check the mobility and fit of the new knee joint. Only then is the appropriate prosthesis fitted. In the final phase of the operation, the surgeon closes the wound and creates a drainage so that the wound secretion can drain off.
Self-service or health insurance – who bears the costs?
The costs for the insertion of an artificial knee joint are usually covered by the statutory health insurance companies. The prerequisite for this is the medical necessity of the implantation.
Risks, complications and side effects
In about 5 percent of all patients who receive an artificial knee joint, unwanted complications occur after the procedure. These include, above all, infections on the knee prosthesis caused by bacteria, the dislocation of individual parts of the prosthesis and the formation of a (thrombosis). In some cases, the knee prosthesis even loosens early. This is noticeable by pain, instability and a leg deformity. However, few people are affected by these complications.
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My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.