The Hip Joint
The hip is a ball and socket joint. It is lined by articular cartilage and is filled with joint fluid contained within a ligamentous capsule. Many diseases may affect the joint but the commonest is osteoarthritis. The simplest way to understand this process is that the joint has “worn out” through usage and that the articular cartilage has gone, causing bone to move (articulate) on bone which can be painful.
When is a hip replacement necessary?
Hip replacement surgery may be required if one (or both) of your hip joints are damaged and are causing you continual discomfort which is preventing you from completing your daily activities. For example; walking, driving or flexing down to your feet. A significant number of patients also find that the pain interferes with their sleep.
The need for a hip replacement increases as we age. With a significant increase in frequency from about 60 years old onwards. However, a hip replacement can also be necessary for younger people.
A hip replacement is very effective at removing pain from an arthritic hip joint. It is said to be one of the greatest medical advances of the 20th century. Once pain is relieved, patients can typically return to hobbies and sports that the hip pain prevented.
What the surgery involves
For a hip replacement to be performed the patient will require an anaesthetic. Most patients where possible, have a spinal injection to numb the legs temporarily – this is great for immediate post operative pain control. Sedation or a general anaesthetic is usually also given.
There will be a scar over your hip. A small incision is typically used but its length is dictated by the size of the patient. Initially, you will be relieved of your arthritis pain but have some surgical pain around and deep to the scar. This typically settles quickly within one to four weeks following the surgery.
Antibiotics are given prior to surgery and for 24 hours afterwards to help prevent infection of the implant.
Some patients will have a urinary catheter inserted after the anaesthetic. This helps nursing and toilet care in the first 24 hours before the patient is fully mobile.
A total hip replacement involves removing the native ball and socket joint being replaced with an implant. A total hip replacement is composed of the following; a femoral stem, a femoral head (ball) and an acetabular component (cup).
The native femoral head is removed. The socket is prepared to accept an acetabular component. Then the femur is prepared to receive a femoral stem which has a femoral head mounted on it. The implant combination is then trialled to ensure that the hip joint is stable and that the patient’s leg lengths are equal.
The implants used depend on the patient’s needs, anatomy, age and activity levels. Two categories exist; those that are cemented into the patient and those that are uncemented which rely initially on an initial frictional fit and then subsequently the bone grows onto the component. Different bearing surfaces are available, but typically a metal on polyethylene or a ceramic on polyethylene bearing is used.
The surgery usually takes about an hour excluding anaesthetic time.
The Recovery Process
After the hip replacement the patient will be able to walk on it the next day, or that evening – if you recover quickly from the anaesthetic.
After the operation you will need walking aids, such as walking sticks, for the first four to six weeks. Many patients have discarded them before their first follow-up appointment at six weeks.
It is often recommended that you undertake physiotherapy to help you regain and improve the use of your new hip joint. However, the best medicine is to use the new hip by walking as much as possible.
Two weeks after surgery the wound is reviewed and paper stitches are removed. This is an easy and painless procedure.
An anticoagulant will be prescribed for 28 days following the surgery to help decrease the risk of a deep vein thrombosis (Blood clot in the leg veins). During the inpatient stay mechanical foot pumps will also be employed to help decrease this risk.
Some patient’s experience swelling and bruising of the leg after undergoing hip replacement surgery. This is normal. If you experience painful or worrying swelling a scan maybe required to rule out a deep vein thrombosis.
The majority of people can resume normal activities within two to three months but it can take up to a year until you experience the full benefits of your new hip.
Driving is allowed after the six week check up, if all is proceeding normally.