Shoulder Replacement Surgery Adelaide

There are numerous types of shoulder replacements and brands, but it comes down to two main varieties. One is a standard anatomic shoulder replacement which is done when the bones and tendons around the shoulder are of sufficient quality to allow a replacement based upon normal anatomy. In this scenario when there is bone rubbing on bone, the ball is replaced with an artificial ball and the socket is replaced with a plastic socket. These days the more common socket is one that is cemented into the bone. These are not dissimilar to the sort of design as a total hip replacement, however while the original designs would have looked very similar to a total hip replacement, the new varieties have evolved so much that they have become very shoulder specific. As in all standard shoulder replacements, the risks include the implants loosening with time.

The reverse shoulder replacement is designed for those situations in which the tendons supporting the shoulder are deficient. This is known as a rotator cuff tear. If a rotator cuff tear is small then this is often ignored and an anatomic shoulder replacement is used but in those where there is significant deficiency minor subluxation leads to excess stresses being placed on the shoulder such that an Anatomic shoulder replacement would loosen prematurely. With a deficient rotator cuff, the Anatomic shoulder replacement would not function well, and in these scenarios a reverse shoulder replacement is employed.

A reverse shoulder replacement, as the name suggests, is where the implants are reversed; the ball is placed where the socket is and the socket is placed where the ball is. This leads to an unusual looking x-ray and certainly is a unique design.

The initial concept was developed in France over thirty years ago but has only been well adopted over the last fifteen years.

Initial scepticism regarding how well such implants would work, and the implant last for, has been allayed as these implants are looking to actually perform very well and have quite good longevity. It is now the most common style of shoulder replacement performed in Australia. 

The Arthroplasty Register, of which the shoulder forms a subset, incorporates eight year results of shoulder replacements and it transpires that the actual longevity for both standard and reverse shoulder replacements is looking at approximately a 5% revision rate over eight years.  This means that one in twenty have had to have further surgery.  In fact, the reverse shoulder replacement has slightly better results than the anatomic one, although the reasons for this may rely on the fact that traditionally the reverse shoulder replacement is done in an older patient age group. ­

Are the protocols any different for reverse or anatomic shoulder replacement?

Shoulder replacements have always been available for arthritis, however traditionally in those patients who have fractured their shoulder in such a way that the anatomy cannot be restored appropriately, shoulder replacements have been incorporated. Traditionally this has been in the form of a hemiarthroplasty (replacing the humeral bone to restore the shape of the ball). But, as is often the case with fractures of the shoulder, the attachments of the tendons to the proximal bone are often disintegrated and as such the healing potential of these fragments is often poor, especially in patients who often are not in the best of health.  As such, in the past a hemiarthroplasty (half a shoulder replacement) has traditionally had poor outcomes in that the movement has been sub-optimal.  Over the last ten to fifteen years people have increasingly used reverse shoulder replacements for such fractures, which do not require these tendons and bone to be healed, ie if the tendons and fragments don’t heal correctly the shoulder replacement can still function well.