This procedure is carried out for shoulder arthritis. There are different types of replacement for different problems. Factors such as the degree of bone destruction will influence the type of replacement used. Often a CT scan will help assess any deformity or bone loss. The state of the rotator cuff also has a significant bearing on the outcome of any operation.
The principles are to replace the arthritic joint with metal/polyethylene surfaces.
Although there is debate, it is generally thought best to replace if possible both the ball and socket of the shoulder, this should give more durable pain relief and better movement than half a replacement.
The X-ray shows an arthritic shoulder that has had a shoulder replacement, this is a stemmed humeral head replacement with a polyethylene socket.
In cases of rotator cuff arthropathy there is debate about which type of replacement to use, the rotator cuff is absent which means there is difficulty with lifting of the arm against gravity. Conventional shoulder replacement can offer good pain relief but does not usually improve the movement of the arm.
One design acts to change the mechanics of the shoulder to regain movement of the shoulder and improve pain. This is called a reverse total shoulder arthroplasty, this increases the moment arm of the deltoid.
The diagram shows the ‘reverse’ nature of the implant.
This does have some risks in addition to conventional replacement with a risk of dislocation,as the long term effects on the deltoid muscle may result in fatigue in this muscle after 7 to 10 years.
Reverse total shoulder is also used in salvage situations such as revision shoulder replacement or after fracture where either there is a malunion (distorted anatomy) or there is rotator cuff failure.
X-rays show cuff tear arthropathy and a reverse total shoulder replacement.