Hip surgery

Your doctors will always try other measures before they consider surgery – for example, painkillers, physiotherapy and/or walking aids. There are also less major types of surgery which can be considered, such as cleaning out the joint (debridement) using keyhole surgery techniques.

All hip replacements are major operations and your surgeon will discuss the possible risks and benefits with you before you decide whether to go ahead. There are no upper or lower age limits for having hip surgery, but the earlier you have surgery the greater the chances that you will eventually need further surgery.

Freedom from pain is the main benefit of surgery – along with improved mobility and better quality of life.

However, an artificial hip does have some limitations – for example, extreme positions such as squatting aren’t recommended because of the risk of dislocation.

A few patients have some pain around the hip after the operation. This may be persistent and it isn’t always possible to find the cause. However, the vast majority of people who have hip replacements don’t have continuing pain.

After the operation, you may find that one leg is slightly longer than the other, but this can be corrected with an appropriate insole (shoe insert).

The joint components will wear in time, and can sometimes loosen. Repeat hip replacements (revision surgery) are possible, though the benefits usually diminish slightly with each revision.

There are two main types of hip replacement operation, but a variety of different components and surgical techniques that may be used.

Total hip replacement (THR)

In a total hip replacement, part of the thigh bone (femur) including the ball (head of femur) is removed and a new, smaller artificial ball is securely fixed into the rest of the thigh bone. The surface of the existing socket in the pelvis (the acetabulum) is roughened to accept a new artificial socket that will join up (articulate) with the ball component.

Many artificial joint components are fixed into the bone with acrylic cement. However, increasingly and especially in more active patients, one part (usually the socket) or both parts may be inserted without cement. If cement is not used, the surfaces of the implants are roughened or specially treated to encourage bone to grow onto them. Bone is a living substance and, as long as it is strong and healthy, it will continue to renew itself over time and provide a long-lasting bond.

The replacement parts can be plastic (polyethylene), metal or ceramic, and are used in different combinations. The harder materials allow better lubrication of the joint, which means that the components should wear more slowly.

• Metal-on-plastic (a metal ball with a plastic socket) is the most widely used combination.
• Ceramic-on-plastic (a ceramic ball with a plastic socket) or ceramic-on-ceramic joints are often used in younger, more active patients.
• A metal or ceramic socket is most likely to be used in very active patients. These sockets are thinner than plastic ones, which means that a larger ball component can be used. This gives a greater range of movement and reduces the risk of the dislocation, allowing more vigorous exercise.

Metal-on-metal (MOM) hip resurfacing

Resurfacing the original socket and the ball of the thigh bone is a more conservative form of hip replacement – less bone is removed than in a total hip replacement. Instead of removing the head of the thigh bone and replacing it with an artificial ball, a hollow metal cap is fitted over the head of the thigh bone. The socket part of the joint is also resurfaced with a metal component.

People who have this type of operation usually recover more quickly, and the risk of dislocation is lower, allowing the patient to take part in more vigorous sports.

MOM resurfacing isn’t suitable for people with low bone density or osteoporosis where the bones are weakened.

Little is known about the long-term performance of these joints as the technique has not been in use for as long as total hip replacements. However, experience so far suggests that resurfacing gives the best results in younger, more active men.

Minimally invasive surgery (MIS)

Minimally invasive surgery is a technique that requires a much smaller incision and results in less damage to the soft tissues (muscles, tendons and ligaments). This should mean a shorter recovery period after the operation. There is no real benefit of MIS in the longer term compared with traditional hip replacement techniques, and some people feel the results may not be quite as good. This may be because it is more difficult to position the implants.

At present MIS is used in only a small proportion of hip replacements. However, it may become more widely used in future, possibly in conjunction with computer-assisted surgery (CAS). CAS (also known as image-guided surgery) uses infrared beacons attached to the patient’s body and to the operating tools to generate images of the inside of the joint. This should allow very precise positioning of the hip replacement components.

Blood clots – Some people can suffer from blood clots which form in the deep veins of the leg (deep vein thrombosis, or DVT), causing pain or swelling in the leg. There are various ways to reduce the risk of this happening, including special stockings, pumps to exercise the feet, and drugs such as warfarin or heparin.

Pulmonary embolism – In a small minority of cases blood clots, particularly those in the thigh veins, can detach and travel to the lungs. This can cause sudden breathlessness, chest pains or collapse. It’s important to get medical advice straight away if you develop these symptoms shortly after surgery, as pulmonary embolism can sometimes be fatal.

Dislocation – Sometimes an artificial hip may dislocate. This occurs in less than 1 in 20 cases, and the hip needs to be put back in place under anaesthetic. In most cases this will make the hip stable, although you’ll probably need to do exercises to strengthen the muscles or have a brace to keep the joint still. If the hip keeps dislocating further surgery may be needed to stabilize it.

Infection – To reduce the risk of infection, specially ventilated ‘clean air’ operating theatres are often used, and most people will be given a short course of antibiotics at the time of the operation. Despite this, a deep infection can occur in about 1 in 200 cases. The infection can be treated but the new hip joint usually has to be removed until the infection clears up. New hip components are then implanted 6–12 weeks later.

Wear – Plastic hip sockets may wear in time. The worn particles of plastic may cause inflammation and this can eat away the bone next to the new hip. Ceramic-on-ceramic or metal-on-metal joints tend to wear less and are therefore less likely to cause this problem. And new, harder-wearing plastics are also being developed.

Loosening – The most common cause of failure of hip replacements is when the artificial hip loosens. This is most common after 10–15 years. It usually causes pain and your hip may become unstable. Loosening is usually associated with thinning of the bone around the implant, which makes the bone more vulnerable to fracture. Fracture around the implant usually requires surgical fixing of the fracture and/or revision of the implant.

Pre-admission clinic

Most hospitals invite you to a pre-admission clinic, usually about 2 weeks before the surgery. You will be examined to make sure you are generally well enough for the anaesthetic and the operation. You’ll be able to discuss the possible complications, and may receive further advice about what you need to do before and after the surgery.

You should discuss with your surgeon whether you should stop taking any of your medications before you have surgery. Some surgeons advise stopping non-steroidal anti-inflammatory drugs (NSAIDs) or methotrexate.

It’s also useful to speak to an occupational therapist who will discuss with you how you will manage at home in the weeks after your operation, and advise on aids and appliances that might help you.

Before the operation

You will usually be admitted to hospital the day before the operation or early on the day of surgery, though it may be earlier if you haven’t attended a pre-admission clinic.

You’ll be asked to sign a form consenting to surgery, and you may also be asked if you are willing for details of your operation to be entered into the National Joint Registry (NJR) database. The NJR collects data on hip and knee replacements in order to monitor the performance of joint implants.

You will probably be given a tablet or an injection to sedate you (a ‘pre-med’), before being given an anaesthetic. This may be either an epidural or a spinal anaesthetic, or alternatively a general anaesthetic. If you have the spinal or epidural you will be sedated if necessary during the course of the operation.

After the operation

When you leave the operating theatre you will usually have an intravenous drip in your arm to give you any fluid and drugs you may need. You will also have one or two suction drains in your hip – plastic tubes that drain away fluid produced as the body heals.

You’ll be taken to a recovery room or high-care unit until you’re fully awake and the doctors feel that your general condition is stable. Then you will be taken back to the ward, often with a pad or pillow strapped between your legs to keep them apart.

You’ll be given painkillers to help relieve pain as the effect of the anaesthetic wears off. The drip and the drains are usually removed within 24–48 hours. You will then be able to start walking, first with a frame and soon with elbow crutches or sticks.

How quickly you get back to normal depends on many factors – including your age, your general health, the strength of your muscles, and the condition of your other joints. If the surgeon feels all these factors are favourable, s/he may include you in an accelerated rehabilitation programme. You would then start walking on the day of the operation and would be discharged within a day or two.

Physiotherapy and occupational therapy

The physiotherapist will see you in hospital after the operation to help get you moving and advise you on exercises to strengthen your muscles. The physiotherapist or an occupational therapist will tell you the dos and don'ts after hip surgery – how to get in and out of a bed, a chair, the shower etc. It’s very important to follow this advice.

You should not bend the hips to more than 90º (e.g. squatting, or sitting in a low chair or couch) and never cross your legs, because these positions could dislocate your new hip. The occupational therapist will advise you on the correct height of seating.

The occupational therapist will assess your physical ability and your circumstances at home, and may provide you with equipment such as a raised toilet seat and gadgets to help you dress.

Going home

How soon you can go home depends on how well the wound is healing and whether you will be able to get about safely at home. Most people are ready to leave hospital within  4–8 days, though it can be sooner for those on an accelerated rehabilitation programme.

You’ll need to attend the outpatients’ department, usually 6–12 weeks after the operation, for a routine check-up. You may also be offered outpatient physiotherapy.

Once you are home the district nurse will change your bandages and take out any stitches. If you have any problems with your wound healing then you should tell the hospital staff straight away.

Looking after your new hip joint

You may not be able to bend your leg towards your stomach as far as you would like – it’s important not to test your new joint to see how far it will go. You need to take great care during the first 8–12 weeks after the operation to avoid dislocating the hip.  However, it’s also important to continue with the programme of muscle-strengthening exercises recommended by your physiotherapist.

Getting back to normal

You can expect to drive again after about 6 weeks, and you could also return to work at this stage if you have a job that doesn’t mean too much moving around. Getting in and out of a car can be difficult – you’ll need to sit sideways on the seat first and then swing both your legs around together. Some people put a plastic bag on the car seat to make it easier to swivel round. The occupational therapist will advise you about other movements where you need to take special care.

You will probably need walking sticks for the first 4–6 weeks. However, this varies between individuals – your surgeon or physiotherapist will be able to advise how well you are progressing.

You’ll probably be able to have sex after about 6–8 weeks, although you should avoid extreme positions of the hip. Don’t be afraid to ask for advice about suitable positions.

Regular exercise is very important. Walking and swimming are fine (but avoid breaststroke when swimming). Cycling may be difficult until about 12 weeks after the operation, as it will be hard to get on and off the bike.

You should avoid running on hard surfaces and sports that involve sudden turns or impacts – for example, squash or tennis. If in doubt, ask your surgeon or physiotherapist for advice. It’s advisable always to avoid extremes of movement at the hip and activities with a high risk of falling – such as skiing.

Revision surgery

Repeat hip replacements are possible, though revision surgery is more complex than the original operation, and the benefits diminish slightly with each revision. Even so, over 80% of patients report success for 10 years and more.

Some revisions may need a bone graft (where a piece of bone is taken from another part of the body or the thigh bone to help make the repair). Bone grafts may need protection from movement, and this might mean that you will be on crutches for longer. However, the eventual result is usually good.