Custom Hip Replacement

The hip is a ball and socket type joint. It is formed by the acetabulum (socket) and the femoral head (ball). Arthritis of the hip is a condition where the joint surfaces become damaged and irregular. The causes of arthritis include age-related ‘wear and tear’, chronic inflammatory disease, traumatic arthritis, avascular necrosis, fractures of the hip, dislocations and some birth defects.

A normal hip joint               An arthritic joint

The treatment options for osteoarthritis may include doing nothing, analgesia, activity modification, walking aids, injections and a total hip replacement (THR). A THR is an operation performed to replace the damaged hip joint. The procedure involves cutting the skin and putting a cup (shell and liner) into the acetabulum. A stem is put into the femur with a ball on the top (called a head).

Can a hip replacement be avoided?

Hip replacement surgery is usually performed when degenerative changes in the hip joint result in severe pain. It may be possible (and beneficial in some situations) to delay surgery and try to loose weight. This may help symptoms by reducing the force going through the joint and reducing pain. Rehabilitation can help to strengthen muscles around an arthritic joint and give confidence but will not reverse the degenerative changes. Injections may improve the symptom of pain, however, none of these treatments will reverse the degenerative changes associated with arthritis.

A Total hip Replacement

There are many different types of hip replacement designs. Some surgeons advocate the use of robots or computer navigation technology to help make accurate cuts. This technology is limited at present.

Younger patients may benefit from ‘mini-hip’ or resurfacing hip replacements. The idea is that less bone is removed using these hips, but there may also be some disadvantages.

Another technology is the use of custom selected or made hip replacement implants. This involves obtaining a CT scan before surgery. Mr. Asopa uses this technology aims to restore the hip anatomy as it may provide superior outcomes compared to standard off-the-shelf total hip replacements. Further information is available from Symbios Orthopaedics.

‘Pre-rehabilitation’ or physiotherapy before surgery to strengthen muscles and improve range of motion may help early recovery and improved outcomes following surgery.

What is a Resurfacing Arthroplasty (or Replacement)?

A resurfacing hip replacement is where only the surface of the femoral head is removed and a cap placed onto it (usually metal and with a small stem). The damaged bone in the socket (acetabulum) is removed and a cup is placed inside the socket (like in a total hip replacement). A resurfacing hip replacement is different to a total hip replacement because a long stem is not put into the femur. The head is smaller on a total hip replacement.

The Operative Technique

A THR involves opening the hip and removing the ball (femoral head) and clearing the surface of the socket (acetabulum). A metal cup with either a ceramic or polyethylene liner is placed into the socket. A metal stem (with or without cement) is fixed into the femur. A metal or ceramic head is applied to the top of the femur. The soft tissues and muscles are repaired following surgery.

How are stem and sockets fixed into the bone?

The cup (or socket) and stem can be fixed with or without cement. Cement acts as a ‘grout’. Uncemented hip replacements depend on bone growing into the surface to achieve fixation.

How long does it take for bone to grow into a hip replacement?

In an uncemented hip replacement it can take 4-6 weeks or longer for bone to grow onto the surface of the implant. Sometimes it may take longer.

The benefits of Total Hip Replacement surgery

The aim of surgery is to eliminate the pain and stiffness experienced with arthritis.

Risk of Surgery

The risks of hip replacement surgery include infection, deep vein thrombosis and pulmonary embolism (blood clots), pain, stiffness, damage to nerves (causing numbness or weakness which may be temporary or permanent) and blood vessels. There is a risk of dislocation and leg-length discrepancy, fracture of the bone, and persisting pain. Death is a rare. Hip replacements are mechanical devices. They have a failure rate of under five percent at 10 years. There are risks related to the anaesthetic. The anaesthetist will discuss these with you. You will be asked to sign a consent form following a discussion of the risks of surgery.

What to expect on the day of surgery?

On the day of surgery, you will see the surgeon and anaesthetist. The anaesthetist will discuss anaesthetic options. These may include general or regional anaesthetic. The nurses will prepare you for the operation. The surgical procedure takes approximately two hours. Near the end of the operation, the hip will be injected with local anaesthetic to reduce the pain. Afterwards, you will go to recovery. When you have safely recovered from the anaesthetic, you will be sent to the ward. You will be given antibiotics at the time of surgery to prevent infection. These may be continued afterwards. You will be given blood thinners following surgery which will need to be continued following discharge.

After the operation

You will be encouraged to mobilise as soon as is safe following surgery. This is to improve the blood flow and give you confidence. As the local anaesthetic wears off, you will experience an increase in pain. It is important that you take your pain killers regularly and continue to work on your exercises during this time. The pain will improve over time.

Length of stay in hospital

There is a general trend in reducing the length of stay in hospital following surgery. Some patients may go home on the same day or the day after. Sometimes discharge from hospital can be after 2-3 days.

How do I look after the hip following discharge?

You need to keep the wound dry and protected using a dressing until it has healed (about 2 weeks). Advice will be given to you before discharge from the hospital. You will be given exercises before discharge.

It is important to plan for physiotherapy following discharge to help with improving the range of motion and strength of the knee.

What you can and cannot do after hip replacement surgery / arthroplasty

You will be given restrictions following surgery to reduce the risk of dislocation. These will include not bending the hip more than 90 degrees (i.e. to get socks on or squatting). You should also avoid crossing your legs. You will need to use pain killers and walking aids for a while after surgery. As you recover and the tissues around the hip heal, you will require less restriction. These will be discussed with you before and after planned surgery.

When can I shower?

The wound is usually protected with a waterproof dressing after surgery. You will be able to have a shower then you feel safe and confident. Keeping the wound dry may reduce the risk of infection for the first two weeks.

When can I have sex?

You may wish to wait for 3-6 weeks before having sex, and avoid some positions that could be unsafe.

When can I return to driving?

It is important to only return to driving when you are safe and able to control your vehicle. Factors to consider are whether you have an automatic or manual car, the position of the seat, what medication are your taking (which could make you drowsy), which side is being operated on and the advice of your insurance company. It may take about 6 weeks to be able to return to driving.

What is the tine frame for blood clots after surgery?

Blood clots can occur soon after surgery, and the risk remains increased for several months. The National Institute for Health and Care Excellence recommends using low molecular weight heparin (a blood thinner) for 28 days following surgery.

Follow-up

The wound will be reviewed two weeks following surgery to ensure that it has healed without complication. If there are any concerns, it is important that the wound is seen by the surgeon.

You will be reviewed six-weeks following surgery to assess your progress.

Rehabilitation

Physiotherapy is useful following discharge. This will be discussed with you.

Do not hesitate to contact me if you require further information.

Acknowledgements

https://commons.wikimedia.org/wiki/User:CFCF

https://commons.wikimedia.org/wiki/User:Mikael_Häggström