With cement-free fixation, the implant is inserted into the bone in such a way that it becomes wedged in the medullary cavity (the inside of the bone which houses the bone marrow). The prostheses are especially designed for this type of anchorage and have particular shape characteristics that ensure wedging.
Aside from the design, the implant surface also contributes to good stability. Depending on the model, the prostheses have a rough surface into which the bone can grow after some time (a process known as osseointegration). If the bone mass is of sufficient quality and mass, cement-free anchorage is usually preferred.
If the bone structure or quality is no longer as stable as necessary – in cases of osteoporosis, for example – the individual implant components are cemented into the bone.
The cement is a plastic consisting of two separate components (a monomer and a polymer phase). The phases are mixed immediately before application and filled into the bone. The prosthesis is then inserted into the still mouldable cement. After curing, the cement ensures stable anchorage of the implant in the bone.
The bone cement is highly biocompatible and can be enriched with antibiotics to prevent infections.