Coordinating Institutions

HIP ENDOPROSTHESIS DESCRIPTION


What tasks does the healthy human hip perform?

The hip joint is called a ball and socket joint and connects the torso to the legs. It consists of a hip socket which is situated in the pelvic bone, and a hip ball or head, which is situated right at the top of the thigh bone. In a healthy hip, both the socket and the head are covered with a layer of cartilage. The joint itself is surrounded by a joint capsule. In the joint space (between the hip head and the hip socket) there is some joint fluid which allows the hip head to slide smoothly inside the socket with every movement.

Diseases of the hip joint

Serious diseases of the hip joint can make it necessary to replace the natural joint with an artificial hip. The most well known and frequent cause of disease is arthrosis (wear and tear). Many congenital and acquired illnesses, as well as injury, can also lead to deterioration of the joint.

In a healthy hip, the cartilage layer has a smooth surface. Deterioration through disease leads to distinct steps forming in this layer, making smooth contact inside the joint impossible. The hip head and socket change shape and the layers of cartilage on the head and socket rub off against each other more and more.

This process leads to pain when weight is put on the joint , when walking short distances, and eventually also when at rest. If all the possible treatment methods apart from surgery do not result in more freedom from pain and restore mobility, only replacement with an artificial hip can improve your quality of life.



What is an artificial hip?

The idea of replacing the hip joint, with its relatively simple construction, originated in 1890. Now, around 800,000 artificial hips are implanted annually around the world.

Artificial hips can be sub-divided into partial and total prostheses.

With partial prostheses, only the hip head and the neck of the thigh bone are replaced. The natural hip socket is preserved.

With total prostheses, the hip head, the neck of the thigh bone and also the hip socket are replaced by a total prosthesis. This is more often the case.

Fixing the hip prosthesis into position

Depending on how the prostheses are fixed into position, they are further divided into subcategories of cemented or non-cemented hip replacement. With cemented prostheses, the prosthesis shaft and socket are fixed into position using bone cement. With the non-cemented version, the prosthesis is fixed by the surrounding bone growing into the different components of the prosthesis.

Your doctor will advise you on the type and method of artificial hip most suited to your particular case.

What happens during the operation?

The hip replacement operation is carried out under general or local (spinal) anaesthetic and is completely painless for you. The anaesthetist will decide what is the most suitable method for you and discuss it with you fully. Depending on the particular case, the operation takes between 45 minutes and 2 hours. After making a skin incision about 20 cm long, the muscles are drawn aside to expose the hip joint. The neck of the thigh bone is cut through and the damaged hip head is removed. To prepare for implanting the artificial hip joint, the diseased hip socket is cut out, and the artificial socket fixed into position.

After this, the medullary cavity in the thigh bone is prepared in such a way that the prosthesis shaft can be fitted precisely into position with or without the use of cement. The prosthesis head is placed onto the shaft. Then both halves of the prosthesis are fitted together to form a joint, i.e. the shaft, with the head attached, is fitted into the socket. The muscles are stitched and the wound closed, with tubes being placed into the joint to drain away any build-up of blood on the hip. The tubes are removed 2 days after the operation.

Correct behaviour after the operation

The success of the operation and the durability of your artificial hip depend to a very great extent on the post-operative treatment you will receive and on your own behaviour after the operation. While you are still in hospital, the physiotherapist will help you to learn how to use your hip joint again, so that when you return home you can manage daily tasks, such as washing yourself and getting dressed, on your own.

The hip operation will allow you to enjoy life once more, free of pain and with improved mobility. But please do not forget to visit your doctor for regular post-operative examinations over the next few years.

This allows any complications, which may occur without showing any obvious symptoms, to be recognised at an early stage. You should enter details of your post-operative examinations in the patient's prosthesis card which you will receive together with this patient information booklet.