Hip Replacement

Do I need hip surgery?

The hip is a ball and socket joint. The ball part of the joint is called the head of the femur (the thigh bone) and the socket is called the acetabulum, which is part of the pelvis. When your hip is arthritic and painful the options for treatment are limited (A). Painkillers and anti inflammatories can help temporarily but often the side effects are unpleasant. Sometimes an injection of local anaesthetic and steroid is used to relieve severe symptoms for a few months. With time the hip may stiffen and become less painful, but it may collapse causing the leg to shorten, making surgery more complex (B). Certain conditions may be amenable to keyhole surgery, usually after an MRI scan has been performed (C). If the pain is getting worse and is affecting your mobility, then you might wish to consider having a hip replacement or resurfacing.

Hip replacement

Hip replacement (Total Hip Replacement or THR) is one of the most successful operations in the history of orthopaedic surgery. Many thousands of hip replacements are performed every year and the results are usually excellent. The components are usually made of materials such as stainless steel, titanium and polyethylene. In some cases ceramic and metal bearings are used. The pain relief is dramatic and within a few weeks of surgery most patients are independently mobile. The vast majority of people who have had a hip replacement return to all of their normal activities within a few months of surgery. Total hip replacement can be performed in young patients, such as hip dysplasia (before and after (D) and (E) (cemented and uncemented)) and leg length can be restored.

Cemented vs. Uncemented/Cementless Hip Replacement:

Cemented hip replacements have been around since the 1960s and were the first successful hip replacements available in the United Kingdom, being popularised by centres in Wrightington and Exeter.

They have well published 25-year results, but were largely used in a more elderly and less active patient group.

In most of the rest of the world uncemented/cementless hip replacements are the norm and again have had very good 25-year results.

In the UK and worldwide, the number of cemented hip replacements for some years has been falling and the number of uncemented hip replacements or cementless hip replacements has been increasing.   In the recent UK National Joint Registry database the number of uncemented or cementless hip replacements now exceeds the number of cemented hip replacements being done a year in the United Kingdom.

The reason for the rise in cementless hip replacements is that the population as a whole are living longer, are more active and have higher functioning demands than can be met with a cemented hip replacement.

With cemented hip replacements the bone cement interface and the cement implant interface is inert and therefore with the normal pattern of walking there are tiny microfractures which occur which eventually result in loosening and failure of the implants.

With cementless hip replacements these interfaces are biological and therefore heal as normal fractures or broken bones do.

Cementless hip replacements therefore offer increased longevity in younger high functioning more active patients.

Cementless stems can also be used with cementless cups and this offers the opportunity to use harder bearing surfaces such as ceramic on ceramic or very strong triple cross linked polyethylene on metal, which have better wear properties and can therefore be used with larger more natural sized heads allowing greater movement and function with fewer restrictions on activity and are harder wearing and so less likely to wear out when compared to conventional standard cemented hip replacements.

Cementless hip replacements therefore allow greater function than traditional cemented hip replacements.

High Functioning Hip Replacements:

High functioning hip replacements are used as an alternative to cemented hip replacements and can take the form or either a hybrid hip replacement i.e. a cemented stem and a cementless cup or a totally cementless hip replacement both stem and cup.

They allow the use larger heads such as 36mm or 40mm and therefore offer a higher more natural range of movement of the hip joint and increased function when compared with standard cemented hip replacements.

This therefore largely eliminates the restrictions associated with cemented hip replacements with smaller 22mm or 26mm heads and allows patients to squat, have a normal bath, garden or play on the floor with young children.

In addition the bearing surfaces can be either metal on metal, metal on highly cross-linked durable polyethylene or ceramic on ceramic.

High functioning hip replacements are used in more active high demand individuals and allow full return to activities which may involve squatting, kneeling or other movements which require the hip to bend or flex more than 90 degrees.

With high functioning hip replacements patients can, with exercise, time and perseverance, be expected to return to a more normal life and allows a return to normal sporting activities including tennis, running etc.

In an increasingly more active higher demand elderly population, high functioning hip replacements also help to optimise patients ability to live independently and potentially act as carers for their partner.

Hip resurfacing

Hip resurfacing is a relatively new technique, which was developed to treat painful arthritis in younger more active patients (F). The results are excellent, in many ways better than the results of hip replacement. The risk of dislocation, one of the commonest complications of hip replacement, is virtually eliminated with hip resurfacing. Most patients who have had hip resurfacing return to work and sports within a few months of surgery. Total hip replacements in younger active patients are effective for a few years but then they wear out, particularly if you are working or wish to play sports. When a hip replacement wears out it is likely that the operation will have to be repeated (revision surgery) and sometimes this is quite an undertaking.

Hip resurfacing was developed to try and overcome some of these problems. The resurfacing is made of a durable metal alloy (chrome cobalt molybdenum), which wears only very slowly. Because of this the bearing can be made large enough to fit over the head of the femur, which is removed when a conventional hip replacement is used. If the hip resurfacing fails at a later date, revision surgery is much more straightforward compared with a conventional hip replacement.

Hip resurfacing is still regarded as an experimental operation because it has not been performed for as long as hip replacement. The results in the short to medium term are excellent, but we do not yet know what the long term (10+ years) results are.

What will happen to me?

Hip replacement and resurfacing operations take about one and a half hours and are usually done using a spinal or epidural anaesthetic. The anaesthetist normally uses sedation or a general anaesthetic as well. If you are going to have a hip replacement, the hip is dislocated and the head of the femur is removed. A new socket is placed into the pelvis. Some sockets are made of metal into which your bone grows; others are made of plastic, and are fixed into place using bone cement. Ceramic material may be used as part of the articulation due to its smoothness, reducing friction. A hip replacement stem is cemented into the femur, and the soft tissues are then repaired.

If you are going to have a hip resurfacing, the hip is dislocated and the bone surfaces are prepared using special instruments. The socket has a special coating into which your bone will grow. The femoral component is fixed into place using bone cement. If your bone is found not to be suitable for hip resurfacing during the operation, a conventional hip replacement will be used instead. The risk of this happening will be discussed with you during your consultation.

After the operation has finished you will be observed in the recovery room until the anaesthetist is happy that you can return to the ward. The physiotherapist will see you the next day and will get you out of bed. Over the next few days you will learn how to walk and manoeuvre safely. Most patients will also have hydrotherapy, which they find very beneficial.

After about a week you will be ready to go home. Physiotherapy continues for about a month and after six weeks you will be seen in clinic. At this appointment if all is well you will be allowed to drive. The next follow up appointment is at the one year anniversary of your operation when an X-ray is taken. Further follow appointments will be arranged every few years after that.

Returning to work

Most people find that they are tired for several weeks after surgery. Returning to work too soon is not a good idea as you will find it difficult to concentrate and you might experience problems with your rehabilitation. After about three months from the operation you will probably feel ready to go back to work.

Sports

Many people return to sports such as golf or sailing after about six months from their operation. For other sports you need to discuss your plans with your surgeon. Contact sports are prohibited, but lots of patients play tennis and badminton. Some even return to skiing after hip resurfacing.

Complications

Hip surgery is a major operation and there is a risk that complications might happen. These are often minor and temporary, but sometimes they can be serious and occasionally life threatening. The commonest complications are usually bruising around, or oozing from the wound. Sometimes the leg is swollen for several weeks after surgery and is usually a normal response to the surgery.

Occasionally a blood clot can develop (~ 2%, deep vein thrombosis or DVT) which will need treatment with warfarin for several months. Rarely DVTs can travel to the lungs causing collapse and occasionally death. The risk of this happening is very low, approximately 1:1000 patients, and precautions are taken after surgery to minimize the risk.

Deep infection sometimes happens (~ 1%) and often requires further surgery. Sometimes the components will have to be removed to clear the infection.

If you twist your hip excessively or have a fall it is possible that the hip will dislocate. You will need to have a general anaesthetic to put the hip back, or even further surgery. The risk is low (~2%) and is much lower beyond six months from surgery after the hip has healed.

Sometimes the sciatic nerve can be injured during the operation, resulting in permanent pain and weakness in the leg. The risk of this happening is very low (0.002%).

Your leg can be lengthened or shortened after hip surgery, and you might need a shoe raise to compensate for this. The risk is low (~2%).

Some patients have high blood pressure, heart disease or diabetes and these conditions can increase the risk of having a heart attack or stroke after surgery. The surgeon and anaesthetist will discuss the risks with you before your operation.

Hip Arthroscopy

A relatively small number of conditions may be suitable for keyhole surgery (G). These include problems with the labrum (H) or sealing ring around the socket and loose bodies within the joint. Unlike knee arthroscopy, patients usually need to stay in hospital for one or two days afterwards. See links.

What to do next

The only way to assess your suitability for hip surgery is to have a consultation with an experienced hip surgeon. During the consultation you will be examined and the surgeon will review up to date X-rays of your hips. The surgeon will then advise you on appropriate treatment.