The shoulder joint is a highly flexible ‘ball and socket’
joint situated where the arms meet the upper body. It is formed from the
rounded end of the humerus, or upper arm bone, and a curved recess in the
scapula, or shoulder blade. The joint is strengthened and stabilised by
ligaments and tendons.
Shoulder replacement surgery is the third most common
joint replacement after hip and knee replacements. Like a hip replacement,
shoulder replacement surgery can involve the reconstruction or replacement of
the ball, the socket, or both. This is generally done following damage due to
an accident, or because of the impact of degenerative disease. Unlike hip replacement,
where the main purpose is to enhance movement and to enable someone to be able
to walk easily again, shoulder replacement surgery is generally undertaken for
pain relief.
Why is shoulder
replacement surgery done?
Shoulder replacement surgery is usually undertaken to
correct damage that has resulted from either disease or trauma:
-
Damage
due to disease: the most common disease that affects the shoulder joint is
arthritis. This damages the thick layer of cartilage that normally protects the
end of the humerus and the socket in which it sits. As the cartilage breaks
down, the bare ends of the bones grind together and do not move as smoothly as
they normally would. This in turn results in painful swelling and inflammation
around the joint. If this does not respond to anti-inflammatory treatments,
then shoulder replacement surgery can be performed to alleviate the pain.
-
Damage
due to trauma: even healthy, well protected shoulder joints can be knocked
out of alignment by an accident or injury, causing unprotected areas of the
bones to rub together. This needs to be corrected by shoulder replacement
surgery as the grinding will only make the injury worse. The joint is more
likely to deteriorate, resulting in increasing pain and stiffness.
What types of shoulder
replacement are available?
Shoulder replacement surgery replaces one or more elements
of the shoulder joint with an prosthetic joint. The head of the humerus and the
socket in the scapula are replaced with either metal or hi-tech plastic
compounds. These are designed to function as naturally as possible, mimicking
the structure of the original shoulder joint. Shoulder replacement surgery can
take several forms, including:
-
Partial
shoulder replacement: the socket remains intact and healthy, so only the
head of thehumerus is replaced.
This is known as shoulder hemiarthroplasty.
-
Shoulder
resurfacing: there is limited damage, so the bones can be resurfaced. This
is usually achieved with metal resurfacing on the head of the humerus and the
use of a plastic composite to line the scapula socket.
-
Total
shoulder replacement: whenboth
the ball and socket are significantly damaged, they can both be completely
replaced with prosthetics. This is known as shoulder arthroplasty.
-
Reverse
shoulder replacement: where there is considerable damage to the surrounding
muscles and tendons of the shoulder, known as the rotator cuff, it may be
necessary to rebuild the shoulder the opposite way around. This involves
placing the prosthetic socket on the end of the arm bone and the prosthetic ball
within the shoulder blade.
Shoulder
replacement surgery – how is it done?
Shoulder replacement surgery is done in hospital under
general anaesthetic. The surgeon carefully cuts through the skin and moves
aside the muscles and connective tissue above the shoulder joint to expose the
bones.
The bones of the joint are separated, or dislocated,
to allow access to the damaged sections, which are then cut away and replaced
with prosthetics. These are held in place with either specialist cement or
screws.
The shoulder joint ligaments are checked and adjusted
to ensure maximum flexibility and function of the joint before the wound is
stitched closed. A small tube may be left in place to drain fluids from the
wound site for the first few hours.
After shoulder
replacement surgery
You will need to spend a few days in hospital following
your shoulder replacement surgery and attend physiotherapy for several months
after you are discharged. You will be asked to wear a sling for the first few
days to keep the weight off your new shoulder and you should avoid any lifting
for around six weeks. You should also steer clear of any form of contact sports
for at least six months.
What are the
benefits of shoulder replacement?
Shoulder replacement surgery rarely results in the full
range of movement that you get with a healthy joint, and you may not be able to
raise your arm much higher than level with your shoulder. However, you should
experience significantly less pain than before, and an increase in movement,
function and flexibility.
The success of your shoulder replacement surgery will
depend on the extent of the original damage, the skill of your surgeon and your
own dedication to physiotherapy after your operation.
What are the risks
associated with shoulder replacement surgery?
As with any major surgery, there are established risks
associated with a general anaesthetic. Shoulder replacement surgery also
carries risks of wound infection, bleeding and blood clots leading to
cardio-vascular problems. However, these risks are rare. Your surgeon and
anaesthetist will talk to you before your operation to make you fully aware of
the risks and benefits so that you can make an informed choice.
