A hip replacement is an artificial hip joint. It is used to replace a worn-out joint.
What is a hip replacement?
The use of an artificial hip joint may be necessary when the original joint is so worn out that it causes the affected person constant severe pain. A hip prosthesis is also called a total hip endoprosthesis (TEP) or artificial hip joint. It is one of the implants and is used when the original hip joint is worn out. In Germany, approximately 200,000 people receive a hip prosthesis every year. The use of an artificial hip joint may be necessary if the original joint is so worn that it causes the affected person constant severe pain. This can no longer be remedied by conservative treatments, which is why only the surgical replacement of the joint can provide relief. The most common cause for the use of a hip prosthesis is hip osteoarthritis.
Forms, types and styles
A distinction is made between several types of hip prostheses. For example, there are hip stem prostheses, femoral head prostheses, hip cap prostheses, and total hip arthroplasty. A femoral head prosthesis is given to older people who have a fracture of the neck of the lower leg and for whom a longer operation is not advisable for health reasons. This type of artificial hip joint is used only to replace the fractured femoral head. In contrast, no changes are made to the acetabulum. However, with a femoral head prosthesis, there is the disadvantage of possible injuries to the acetabulum due to more severe impairments. Another type is the hip stem prosthesis. With this type, the neck of the femur is replaced. A stem in the femur is also used as an anchor. The modern variants include the cementless short-shaft prostheses, which primarily include the femoral neck. A hip cap prosthesis is an artificial hip joint in which only the surface joint components are removed. A metal endoprosthesis is used as a replacement. The femoral head and femoral neck can be completely preserved in this form. A hip cap prosthesis makes sense for women up to 60 and men up to 65. If the hip joint is completely replaced, it is called a total hip endoprosthesis. It is composed of a ball head, the acetabulum and the hip stem. The surgeon places the ball head on the hip stem, which in turn is implanted into the thigh bone. The acetabulum is implanted onto the pelvis.
Structure and function
Important for the function of the artificial hip joint are the materials used for the prosthesis. This is how the artificial joint meets the natural bones. In this process, the materials must ensure a pain-free movement process. At the same time, it is important that the foreign materials are tolerated in the long term. The hip prosthesis has the task of imitating the function of a natural hip joint. Depending on the type of hip prosthesis, the implant consists of up to four components. These include the acetabular component, which is anchored in the pelvis, and the hip prosthesis stem, which the surgeon attaches in the femur. Another component is the femoral head component. In the case of a hip cap prosthesis, this is implanted on the bone of the femoral head that is still intact. If it is a hip prosthesis stem, it is attached as a ball head. The fourth component is a plastic inlay. This rests on the acetabular component and ensures that the femoral head component slides. In order for the hip prosthesis to fulfill its functions, it is necessary to connect the respective components to the hip bone. There are basically three options for anchoring the artificial hip joint. These are the cementless hip prosthesis, the cemented total hip endoprosthesis, and the hybrid prosthesis. In a cementless hip prosthesis, the prosthesis stem and the artificial acetabulum are screwed to the bone. Over time, the hip bone can grow together with the surface of the prosthesis, resulting in a stable unit. In the case of a cemented hip TEP, the surgeon uses a special cement that hardens quickly. The socket and stem are cemented together, creating a bond between the bone and the prosthesis. A mixture of cemented and cementless hip prosthesis forms the hybrid prosthesis.Here, the socket of the prosthesis is attached without cement, while bone cement is used for the stem.
Medical and health benefits
There are several benefits to having an artificial hip joint, provided that the course of the surgery is successful and the patient cooperates well with physicians during follow-up care. The primary health benefit of a hip replacement is a significant improvement in pain. In some cases, even complete freedom from pain is possible. Since the functions of the hip joint also improve again, this has a positive effect on the patient’s quality of life. The patient can move around better again, walk longer and even go on hikes and bicycle tours. Using cars or public transportation is also easier again. Putting on clothes and personal hygiene are also easier. For example, the patient can put on his shoes or cut his toenails more easily again. In addition, certain sports activities are possible with a hip prosthesis, although this also depends on the type of sport and the patient’s age. Despite all these advantages, the implantation of an artificial hip joint also involves some risks. For example, there is a risk of inflammation by bacteria, the formation of a blood clot, or injury to the blood vessels or nerves. Likewise, dislocation of the hip prosthesis or leg length discrepancy may occur. If material wear or loosening of the prosthesis occurs, the artificial joint must be replaced prematurely, but this is rare.
