In order to benefit from your artificial joint for as long as possible, it has to be firmly anchored in the bone. There are three recognised techniques available for anchoring the endoprosthesis:
Bone cement and more: how the artificial joint is held in the bone
- Cemented endoprosthesis:
In this case a polymer, referred to as a bone cement, is used to fix the endoprosthesis. A cemented endoprosthesis can bear weight immediately after joint replacement surgery and thus enables the patient to get moving again quickly. In order to prevent the joint from becoming infected, an antibiotic-loaded bone cement can be used. One example of a bone cement that has been used and trusted for more than 60 years is PALACOS® from Heraeus Medical.
- Cementless endoprosthesis:
Alternatively, the surgeon can anchor the artificial joint without bone cement. In this case, the bone slowly grows into the endoprosthesis and only creates a firm connection after some time.
- Hybrid endoprosthesis:
This is the combination of a cementless and cemented endoprosthesis. Part of the endoprosthesis is anchored with bone cement, while the other part is fixed without cement.
The procedure used for each individual case depends on a number of factors, including the age of the patient, any pre-existing conditions, such as diabetes and the bone quality. Globally, regional differences and the training of surgeons also play a role in the choice of endoprosthesis and surgical technique used.
Studies show that cemented endoprostheses have a particularly long lifetime. This prevents the need for surgery to replace joints or at least defers it for a long time. The infection risk is also significantly reduced when using an antibiotic-loaded bone cement.
An aside: what is bone cement exactly?
Bone cement is not actually a cement, but is instead a polymer made up of two components. The technical name is polymethyl methacrylate (PMMA). It is mixed up from a liquid and powder immediately before insertion of the artificial joint, and then cures completely within a few minutes. Bone cement enables the endoprosthesis to be firmly anchored and thus enables force to be transferred between the bone and the artificial joint. Bone cement has been successfully used for more than 60 years to anchor artificial joints.