Joint Replacement

There are many types of joint replacements which are available to the specialist shoulder surgeon. The choice of prosthesis must match the needs of the patient and the nature of the condition the patient has, such as the age of the patient, the quality of bone, the state of the rotator cuff muscles, whether intact or non functioning, or if replaced with fatty degeneration. Therefore the correct prosthesis can only be determined by consulting your shoulder specialist, being investigated usually with Xray, Ultrasound and MRI and then discussion with the specialist and your family. Here are some of the choices.

Fortunately the expectations and results of the shoulder joint replacements are markedly improved over the last 10 years and generally good pain relief and much improved function can be achieved with the appropriate selection of the correct prosthesis.
 

Total Shoulder Replacement (TSR)

There have been many advances in shoulder joint replacements over the last 20 years. The first generation artificial joints were basically one size to fit all, but of course people are

of all different sizes and so many did not fit all that well and would loosen.

The second generation of shoulder prostheses allowed for different sizes of the ball and socket as well as the length and width of the arm bone so allowed better fit and function.

The third generation of shoulder joint replacements were only released for world distribution in 1999 although designed and trialled for a period of 8 years in France (Walch,

Boileau) with impressive results. These allow the normal shape of the patient's joint surfaces to be exactly reproduced in surgery, so the patients muscles can act normally and therefore better function is achieved as well as the good pain relief.

The old worn out ball of the head of humerus is removed and a highly polished metal surface (part of a sphere) is replaced on the humerus which exactly fits on the cut surface. Usually a plastic cup is cemented onto the scapula (shoulder blade) on which the smooth metal slides. Thus friction is minimised, the painful surfaces removed and the muscles which move the joint returned to their correct length.

 Postoperatively

1. Patient stay 3 - 5 days in hospital for pain relief and physiotherapy, until they are independent and can look after themselves.
2. We encourage early movement of the shoulder at first in a sling but this can be removed quite early for periods but will be useful for upto 6 weeks.
3. Hydrotherapy is extremely useful to help relax muscles, regain movement in a soothing less painful environment and can be begun after 3 days if facilities are available, as a waterproof dressing is applied in theatre to cover the wound. The sooner the return to function the better the eventual result.

Resurfacing

In the younger patient or if only the joint surface of the humerus is involved the least destructive alternative may be the resurfacing of the head of humerus (ball) with a highly polished cap. Often it is not necessary to place a plastic cup in the glenoid although that is available in certain circumstances (please discuss with your surgeon). These have been used in England by Mr. Stephen Copeland and more recently gaining popularity over here as well as in the rest of the world.
Less bone is removed as no stem is necessary, but the approach is similar to the anatomical joint replacement and so rehabilitation is similar.

 

Reverse Total Shoulder Replacement

For Cuff Arthropathy when there are no muscles or cuff remaining about the shoulder joint (which is also worn out), there used to be no good solution. The standard artificial joint relies on the surrounding muscles to hold it in position and to move it. When these are not present then the metal prosthesis migrates upwards and erodes the acromion bone causing more pain, sometimes necessitating a joint fusion ( not well tolerated in older people).

In 2000 a Reverse shoulder prosthesis was released for use in Australia which was designed specifically for this condition. By fixing the hemi-ball to the scapular,the center of rotation is stable, the arm bone (humerus) is held down and not able to migrate upwards to erode the bony arch, and the joint is centered on the shoulder blade. Also it allows the remaining outside muscle (the Deltoid), to act in a more mechanically advantageous manner so that control of the joint is regained, often quite soon after the surgery. This allows patients to open doors, reach for cupboards, eat, attend to their hair and other personal care without holding their arm with the other hand, in addition to reducing the pain - which is the primary aim.

Again this has been used for many years in France (since 1987) prior to its release here with good long term results.

Postoperatively

1. Patient stay 3 - 5 days in hospital for pain relief and physiotherapy, until they are independent and can look after themselves.
2. We encourage early movement of the shoulder at first in a sling but this can be removed quite early for periods and usually not needed after 3 weeks.
3. Hydrotherapy is extremely useful to help relax muscles, regain movement in a soothing less painful environment and can be begun after 3 days if facilities are available, as a waterproof dressing is applied in theatre to cover the wound. The sooner the return to function the better the eventual result.
4. Function returns quicker than convention replacement but there is a limitation of internal rotation (arm behind back - can usually reach bottom but not bra strap)

CTA (Cuff Tear Arthropathy ) prosthesis

If there are no rotator cuff muscles that can be repaired and the wear of the glenoid is concentric with an intact coracoacromial ligament to hold the prosthesis under the archwithout displacing anteriorly or superiorly, then a CTA prosthesis with an extended hood on the ball to articulate with the acromion, may relieve some pain and give moderate active movement. It is useful in the younger patient as it removes less bone and can later be revised to a Reverse type prosthesis later. It is rarely used now days.
In the older patient it may be better to proceed to the Reverse in the first instance as better function can be achieved earlier, without the need for a second operation later.

 

Trauma Prosthesis

When a shoulder is fractured in multiple peices, in the younger patient a trauma prosthesis is used which allows bone to grow through the implant so that the cuff muscles attached to the tuberosities can unite back to bone, a requisite to regaining control of the shoulder. This is slow, the shoulder is often stiff for up to a year, and the process quite frustrating.
In the elderly, it is often better to replace the fragmented head of humerus with a Reverse prosthesis and start movement immediately.
 

Arthrodesis or Fusion

Before the above advances in shoulder replacements became available some patients needed to have their shoulders fused especially if they had a previous failed shoulder replacement or if their was no cuff and the shoulder was unstable and dislocating either anteriorly or superiorly.

Movement of the arm was still available by moving the shoulder blade about the rib cage although no movement between the arm and the shoulder blade. It often reduced the pain, prevented other problems but had limitations (to be expected).