How is the shoulder endoprosthesis secured?

Cemented or cementless?

An artificial shoulder joint can be secured into the bone in a number of different ways. In essence, there are two main types of fixation: cemented and cementless:

If the bone structure is no longer very stable, the shoulder surface replacement is attached using bone cement. Immediately after the operation, the shoulder endoprosthesis and bone are thus securely bonded.
If the patient’s bone is of good quality, the artificial shoulder joint can be secured using a cementless technique. With such methods, the bone slowly grows into the shoulder endoprosthesis to form a strong joint after some time.

The correct choice therefore not only depends on the patient’s age but also on the nature of the bone. The surgeon decides upon the appropriate method together with the patient during the preoperative discussion.

What happens before the operation?

Cemented shoulder endoprosthesis

With this method, the artificial parts of the joint are bonded to the bone using so-called bone cement.

Question: What is bone cement?: Bone cement is not actually cement but rather a fixation material comprising two components. The liquid and powder are mixed together immediately before the artificial joint is placed, the cement cures completely within a few minutes. The prosthesis elements are thus securely bonded to the bone. Bone cements often contain an antibiotic in order to prevent infections. Bone cements have been successfully used for over 50 years in order to secure artificial joints.

In most cases it is advisable to use bone cement when implanting a shoulder endoprosthesis. The slow bone in-growth of the artificial shoulder joint is avoided and the patient is able to load the arm again soon after the operation, under the supervision of a physiotherapist.

Cementless shoulder endoprosthesis

As opposed to cemented fixation, here the artificial humeral component and the prosthetic cup are wedged into the bone. Consequently, the rough metal surfaces of the prosthesis components are in direct contact with the bone, which gradually grows in. However, the requirement for cementless fixation of the shoulder endoprosthesis is good bone quality.