Diagnosis
The diagnosis is based on anamnesis (family, own anamnesis), physical examination (pain localization) with additional confirmation by x-rays of the affected hip side. Flexion, extension, internal and external rotation, as well as abduction and adduction are checked during a hip joint movement test. In the presence of coxarthrosis, the internal rotation of the hip joint is particularly limited, and the entire leg appears shortened due to muscle shortening.
Types of hip prosthesis
Which type of hip prosthesis is used for a particular patient depends on the patient’s age, bone condition and the degree of hip joint disease. Generally, a distinction is made between partial hip joint prostheses, in which only individual structures involved in the joint are replaced by artificial materials, and the so-called total hip joint endoprosthesis (hip TEP), which replaces all joint structures. Partial hip endoprostheses include the femoral head prosthesis, in which only the femoral head is replaced, but not the acetabulum.
The artificial femoral head is anchored in the femur with a more or less long hip stem (normal or short stem prosthesis). On the other hand, the hip cap prosthesis after McKinn falls under partial endoprosthetics. Here the body’s own femoral head is retained and is crowned with an artificial cap after the original cartilage has been removed.The corresponding artificial hip joint socket is placed “classically” in the pelvic bone.
In contrast, the total hip prosthesis is characterized by the fact that the femoral head and part of the femur as well as the acetabulum are completely replaced by a prosthetic. The material of which the respective implanted hip prostheses are made can vary and vary from patient to patient and from model to model. In addition, a hip prosthesis does not consist of a single material, but usually of several.
The shaft of the hip prosthesis, which is anchored in the femur, is usually made of titanium, as is the prosthesis socket, which will subsequently replace the actual acetabulum. Titanium is often used as a base material because of its stability, durability and good compatibility. The inlay of the artificial acetabular cup, which lies on the titanium cup and can be regarded as a kind of articular cartilage replacement, is on the other hand mostly made of polyethylene (plastic) or ceramic.
Polyethylene is considered to be particularly abrasion-resistant and resistant to oxidation. Ceramics have proven themselves in long-term use and are therefore suitable for younger, more active patients and patients with metal allergies. The joint ball head can also be made of ceramic or modified titanium. Material combinations in the sliding combination are also possible. Basically all hip prostheses and prosthesis components are nickel-free.
