ARTIFICIAL SHOULDER JOINT

If all measures for painful joint wear are unsuccessful, an artificial shoulder joint is a reliable option.

The aim of an artificial shoulder joint is to regain quality of life and mobility if the shoulder wears out or breaks. 

A worn shoulder joint usually causes pain and limits mobility. The quality of life suffers as a result! Implanting a shoulder prosthesis improves shoulder mobility and eliminates pain. 

The computer-assisted implantation of artificial joints on the shoulder with the help of patient-specific CT data, as well as navigation and robotics, is becoming increasingly important. 

A precisely inserted artificial joint exploits the full potential of this technique and leads to convincing results and satisfied patients.

You should pay attention to this when choosing the “suitable” artificial joint.

Artificial shoulder joints consist of body-compatible metal implants made of titanium or cobalt-chrome alloys.

If the head of the humerus is mainly affected by osteoarthritis, for example as a result of a fracture of the head of the humerus, and the joint socket still has a good cartilage cover and no significant deformation, it is usually sufficient to replace only this part of the joint with an endoprosthesis. 

The surface of the humeral head is removed and fitted with a shaft-free prosthesis. This is a procedure that largely preserves the natural bone. 

There is no anchoring with a long prosthetic shaft in the bone of the upper arm. Replacing the pan is also possible. If the head of the humerus and the joint socket show severe cartilage damage and significant deformation, both parts of the joint should usually be replaced. 

This is then referred to as a total shoulder endoprosthesis. The short shaft of the prosthesis is firmly anchored in the bone of the upper arm. In most cases, the socket replacement is cemented into the bone via tenons or a keel on the back of the socket.

Different types of pans are used to treat acetabular osteoarthritis. Pans made of highly cross-linked polyethylene with cement are normally used. 

PE cups with a central fan-shaped central peg can be implanted with bone relining almost without cement because the central peg grows into the bone. 

We differentiate between pans with keel anchoring and those with tenon anchoring. For special indications in cases of advanced bone wear, titanium cups with a polyethylene attachment can also be installed cement-free and are convertible. 

If there is further joint wear after many years, these sockets can be converted into an inverse system. 

If, in addition to osteoarthritis, there is extensive damage to the rotator cuff such that movement of the arm is only possible to a limited extent, a special endoprosthesis may be required.

This implant does not rely on the rotator cuff for joint movement and is called an inverse (reverse) endoprosthesis. Unlike the anatomical prosthesis, the ball is anchored to the joint socket. 

The biomechanical principle of the inverted endoprosthesis consists in the displacement of the center of rotation around which the inverted humeral socket can rotate. 

The lack of strength development in the damaged rotator cuff can be compensated for by the deltoid muscle and the arm can be raised again. 

The ball is anchored in the joint socket without cement using screws. In the upper arm, the endoprosthesis is inserted without cement if the bone quality is good. 

A sliding socket made of polyethylene is pressed into the upper part of the upper arm endoprosthesis, which can then slide around the head. 

The inverse endoprosthesis is usually used in patients aged 65 and over. The prerequisite is that the deltoid muscles are intact.