Artificial shoulder joints
(Endoprostheses)
Even the shoulder can be affected - albeit less often than other joints - by osteoarthritis (abrasion) or rheumatic and other inflammatory diseases. The shoulder joint has a mismatch with regards to the size of the joint partners. A large humeral head and small shoulder blades enable extended movability. The shoulder is - unlike the hips – not led by the fit of the joint partners, but by ligaments and muscles - it is dependent on these soft tissues. Most of the diseases therefore affect these soft tissues (see previous chapter).
Shoulder osteoarthritis occurs after accidents, dislocations, rheumatism, muscle imbalances and due to other factors.
The main method of treatment of osteoarthritis of the shoulder is the conservative treatment: infiltrations, physiotherapy, electrotherapy, laser etc.
As with all other joints, these conservative treatments of shoulder osteoarthritis can also fail . Surgically, the arthroscopic debridement should first be attempted in case of young and active patients. Here dead gristle, bone spurs and inflamed joint lining (synovium) are removed and the joint partners smoothed (see the relevant knee joint technology). This therapy can achieve, at least in the short or medium term, pretty good results.
When the entire cartilage thickness is damaged in a not too wide extent, the autologous chondrocyte implantation (ACI) can be also applied to the shoulder, but the experience here is scarce. The treatment principle of this new method is described in the knee section.
In elderly patients and in those suffering from rheumatism with a destroyed shoulder joint, an artificial joint has to be implanted.
Treatment principle
Like the knee and hip, the used up cartilaginous articular surface of the shoulder and the underlying, mostly already dead bone is removed sparingly, and replaced by a metal implant to the humeral head (hemiarthroplasty) and eventually additionally by an acetabulum implant (total hip). Meanwhile, the fourth generation of shoulder prostheses is already on the market. This new prosthesis design allows a largely anatomical reconstruction of the joint. Special types of prostheses are available even for completely missing or not reconstructable muscle cuffs.
However, it should not be kept secret that the results and achievements of artificial shoulder joints do not compete with those of knee and hip surgeries. Generally speaking, the better the muscles are (or can be reconstructed), the better the shoulder will be movable after surgery. In case of completely destroyed muscle cuffs the pain is usually taken care of, but despite the use of new special prosthesis (Delta prosthesis), it is not always possible to gain complete movability.
Whether a partial or total hip replacement is used, depends on the case and on the state of the socket and the muscles.
Artificial shoulder joint
Aftercare
The hospital stay lasts about two weeks. Getting up possible from the first day after the operation, the drains are removed on the second day. Intensive physiotherapy until the maximum achievable shoulder movability. You may stay in a rehabilitation center.
Working and sporting ability
In case of a high quality of the muscles, slight to moderate work can be resumed after about 4 to 6 months in the ideal case. Except overhead and contact sports, most sports are practicable.
With poor or no muscle, light work (to just below the shoulder height) can be performed.
Results
80 percent of patients achieve a very satisfactory pain relief and increased movability. The "survival" rate of artificial joints is about 90 percent after ten years.
Complications
Seen over a period of 10 years, about 10 percent of the implants loosen up and may require a change of the parts used. If a partial prosthesis is used, it may cause a wear of the shoulder blade. If an endoprosthesis is used, a loosening of the acetabular implant can occur. A rare, albeit serious complication is the joint infection.
Above: Raised shoulder stand, due to torn rotator cuff
The humeral head abuts the shoulder cap and forms a false joint (arrow).
Below: Special prosthesis
X-ray of the special prosthesis