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Total Hip Replacement

What is arthritis?

Arthritis is a degenerative condition of joints which results in damage to the articular cartilage. Large joints such as the knee and hip joints are often affected.

Primary osteoarthritis (arthritis without a cause) of the hip is actually very rare. Most patients with osteoarthritis have an underlying cause.

The most common causes for hip arthritis are trauma, avascular necrosis, hip dysplasia (abnormally developed hip), slipped upper femoral epiphysis (growth plate injury around puberty), Perthe’s disease (avascular necrosis of the femoral head), and infection.

Sometimes hip arthritis can be secondary to inflammatory conditions such as rheumatoid arthritis, ankylosis spondylitis, Reiter’s disease, psoriasis and other inflammatory joint diseases.

Ultimately the articular cartilage of the joint will be severely damaged which may lead to symptoms of pain, stiffness and loss of function.

 

x-ray of osteoarthritic hip
X-Ray showing a osteoarthritic hip

 

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What are the symptoms of a painful hip?

  • Groin pain is the most common presentation of a hip problem.
  • This is often associated with pain going down the thigh and can be associated with referred pain to the front of the knee.
  • The pain is often activity related but can also appear at rest and typically at night.
  • Buttock pain is much less common and may indicate problems with the lower back.
  • The difference between hip pain and back pain can be very difficult to tell apart.
  • Sometimes special test are required to make certain where the pain is coming from.

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What can I do to get rid of my hip pain?

There are a variety of non-operative treatments that can relieve your symptoms of hip arthritis.

It is good to keep as active as possible however you may be required to limit certain activities that excercebate the pain.

Some patients are overweight and some weight loss is very helpful in relieving symptoms.

Arthritis is often causes cyclical discomfort due to inflammation of the synovial lining of the joint. Regular painkillers may be helpful during that period of worsening of symptoms.

Anti-inflammatory medication and pain killers of different strengths may be helpful.

Some patients find other ways of obtaining pain relief such as acupuncture, aromatherapy, reflexology or the use of a chiropractor or osteopath.

Dietary supplements such as glucosamine and chondroitin sulphate as well as omega-3-fatty acids now have scientific evidence that they provide symptomatic relief, especially in knee arthritis.

Detailed information on dietary supplements

Soft shoe inserts may reduce the forces travelling to the hip. This may make walking more comfortable.

A walking stick held in the opposite hand to the painful hip may also reduce pain in an arthritic hip.

Is certain rare cases the use of hip arthroscopy may provide pain relief and delay the requirement for more major surgery.

Eventually, at a time often difficult to determine, conservative treatment measures may not provide adequate symptomatic relief and a surgical solution may have to be considered.

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When should I consider having a hip replacement?

Arthritis of the hip joint has affected mankind ever since we assumed an upright posture. The body’s natural way to deal with a joint that is arthritic is to restrict its movement and make it stiff. After all it is the movement that causes the pain most of the time!

Damage to the cartilage is seen as narrowing of the joint on the X-Ray. Extra bone known as osteophytes develop, which is the body’s attempt to increase the surface area and so reduce the pressure per surface area of the joint. Ultimately when the destruction of the joint is so extensive the joint fuses. Fusion of the joint, also known as “ankylosis”, will stop it from moving and will therefore stop the pain!

The evolution of joint replacement has meant that whereas in the past a patient with an arthritic hip joint would be in pain and have restricted function until the joint fused; now we are able to replace a hip joint and relieve pain and maintain a level of function very similar to the native joint

Hip replacement, is the most successful and cost effective medical intervention. 95% of patients who have a hip replacement will still have a functioning hip 10 years after surgery and about 85% of patients will still have their hip replacement at 20 years.

For patients older than 65 who have a hip replacement 93.5 % should not require any further surgical procedure on that hip.

It is worth remembering that having an arthritic hip is not a life threatening condition. The hip replacement operation is a quality of life procedure. The success rate is very high and the chance of a complication very low.

Before deciding on surgery, the patient should be aware that if a complication should occur it may cause him or her to be worse off. Fortunately the chances of that happening are quite rare.

In the majority of patients the best indication for proceeding to replacement surgery is when the symptoms fail to respond to conservative management and the patient is no longer willing to tolerate the symptoms associated with arthritis.

Further information on total hip replacement

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What hip replacement is best for me?

Like all things in life most people would like to have the best if possible. So what is the Rolls Royce of all hip replacements?

This is a difficult question to answer, as there are many variables involved.

As more studies are being published it appears that there are a great number of different hip systems that can provide good long term outcomes.

The largest data base which looks at how well hip replacements last is the Swedish hip register.

 

The most common types of hip replacement in use are:
Cemented THR Hybrid THR (cup uncemented, stem cemented) Uncemented THR Hip Resurfacing
Cemented THR Hybrid THR
(cup uncemented, stem cemented)
Uncemented THR Hip Resurfacing

 

Each type of hip replacement used today is experimental to some degree. The companies that produce the implants make some small modifications from time to time. After all, if the Volkswagen Golf was the same each year who would buy it after a while?

Your surgeon will discuss what type of hip replacement is best suited for you and he will also discuss the reasons why. Many options are available to each patient and the optimal solution is often reached after discussion with your surgeon.

There is however one certainty. The outcome of a hip replacement is directly related to the correct positioning of the implant and therefore related to the skill of the surgeon.

It is the aim during surgery to recreate the exact biomechanical environment that existed when the patient's original, well functioning, hip was still in place.

This process is called “soft tissue balancing” of the hip.

By doing this the hip joint will be as strong as possible, it will restore the leg length, if there is a discrepancy, and it will reduce the chance of hip dislocation.

It is becoming apparent that fixation of the socket and the femoral stem, whether cemented or uncemented, can last a long time.

The main weakness of a hip replacement, that most often causes it to fail, is the articulation between the ball and the socket also known as the bearing.

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What is soft tissue balancing of the hip?

Your surgeon will try as best as possible to place the new replacement hip in the same “position” as the native hip before it got worn out. This process is know as “soft tissue balancing” of the hip.

This process will allow the replaced hip to function as best as possible by allowing the muscles around the hip to work optimally. It also will allow for deformities, such as leg length problems, to be corrected which in turn reduce the risk of post operative dislocation of the hip.

There are a number of ways by which the surgeon can optimise “soft tissue balancing”.

  • At the time of the initial consultation the leg length discrepancy and other deformities are noted both on clinical and X-Ray examination.
  • Prior to performing your operation your surgeon will “template” the X-Ray. This is the planning of the operation to determine what size of implants are required, where they need to be positioned and what intra-operative corrections need to be made.
  • During the operation a number of tests are carried out to make sure that the pre-operative plan has been successfully executed. This may involve the use of a small jig which allows for the offset and leg length to be measured during the operation.

x-ray of preoperative templating Leg length offset guide
Templating of the X-Rays in order to plan the operation. A side arm jig is used to measure the restoration of leg length and offset during the operation. (Soft tissue balance of the hip)

 

x-ray of right hip protrusio x-ray of hip replacement with acetabular bone graft
This 71 year old lady has osteoarthritis of the hip with protrusio (the femoral head has migrated toward the pelvis). Using the patients own femoral head as graft material the centre of rotation, leg length and offset have been restored.

 

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What types of bearings are there?

The bearing of the hip replacement is the junction between the artificial femoral head and the socket. This is the area where “wear” will occur. Wear is the most common cause of long term failure of the artificial hip joint.

Every time the patient with a hip replacement takes a step some wear occurs between the ball and the socket. This produces wear particles which can, via a complex biological reaction in the body, ultimately lead to bone resorption and loosening of the joint replacement.

Over the last number of years newer types of bearing material have been introduced to see if they are an improvement over the traditional ones, in the hope that they will wear less and theoretically last longer.

The popular bearings at the moment are of three basic types. Each one has their own advantages and disadvantages. The jury is still out in deciding which one is the best.

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Hard on polyethylene bearing

On the socket side a polyethylene bearing has been used almost since the popularisation of total hip replacement. The manner in which these bearing wear is fairly predictable, and unfortunately it is the bearing that produces more wear particles than any other bearing. However, if revision of the replacement is required the techniques are well established.

A more modern type of polyethylene is called highly cross linked polyethylene. Most manufacturers of implants produce a slightly different type of “highly cross-linked” polyethylene. At least in the laboratory this type of polyethylene has shown improved wear characteristics over standard polyethylene. Some early publications using this material are now becoming available showing some promising results.

The “hard” part of the bearing relates to the femoral head. The most commonly used materials for making the artificial femoral head have been cobalt chrome and stainless steel. More recently harder material such as ceramics have been used.

A more recent material that is used to make the femoral head is Oxinium. This is a material used in the oil drilling and nuclear fuel industry which is very hard and scratch resistant. It has been shown in the laboratory and in clinical practice to have reduced wear of the bearing.

 

Oxinium bearing Total Hip Replacement with Oxinium bearing
Highly cross linked polyethylene with Oxinium bearing Total Hip Replacement

 

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Ceramic on ceramic bearing

 

ceramic bearing x-ray of Total Hip Replacement using ceramic bearing
Ceramic on ceramic bearing Total Hip Replacement

 

Ceramic is the hardest bearing with the least wear. Unfortunately it is also brittle and may not be ideal for patient who intend to run or do impact sports. Fractures of this bearing have been reported although with the latest design of implants this is rare and occurs in only 0.004% of patients. A revision operation following a ceramic fracture however does not always have a good long term outcome.

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What are the possible complications of a total hip replacement?

The chances of a major complication are between 1-3 %. Anaesthetic complications are very rare.

For total hip replacement the five most common complications are:

1. Infection
2. Dislocation of the hip joint
3. Injury to the nerves and blood vessels
4. Deep vein thrombosis and possible pulmonary embolism
5. Problems with restoration of leg length

For uncemented total hip replacement there is a 0.3% chance of persistent thigh pain after the operation.

Hip resurfacing has a 1-2% incidence of femoral neck fracture.

Other medical problems. Major surgery can sometimes be followed by other unexpected medical problems including a heart attack, stroke, poor kidney function, the gut temporarily failing to function, constipation or poor bladder function.

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Will the operation be painful?

Of course we expect some discomfort with every operation. However with modern modalities of pain control discomfort will be limited. Mr Busch has published on a method of injecting around the total hip or knee replacement during the time of surgery which makes the peri-operative time very comfortable and allows for early mobilisation.

Publication on peri-articular infiltration

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How quickly will I recover postoperative?

Most patients will be out of hospital in 3-5 days. Some even sooner! The majority of patients have control of their car at six weeks and some leisurely sport can be started at 3 months. The function will continue to improve and will reach the maximum at 1 year to 14 months. Most people will be able to take part in normal walking, playing bowls, golf and tennis. Most patients have no problems with doing gardening. Certain patients will be able to ski and run.

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What can I do with my hip replacement?

A replacement of any joint is never as good as your own original joint. It is however a very good second best! As the longevity of the joint replacement is almost completely dependant on the wear of the bearing surface it is logical to look after the replaced joint as much as possible. If we can compare a hip joint to a car engine we can speculate that if an engine has a million miles to run, a patient can drive all the miles available in just a few years, or by being a little more cautious, can have many years of trouble free motoring.

On the other hand we must not forget that the joint replacement is often performed in order to resume activities which the patient was unable to participate in, because of the arthritic joint.

Most activities can be performed by patients who have a joint replacement. Bearing in mind however that the longevity of a joint replacement depends on the rate of wear, the avoidance of dislocation and infection, any activity that the patient wishes to take part should be viewed within these confines.

Sports such as golf, tennis and skiing are possible with both hip and knee replacement. It is however worthwhile to take some simple actions to stop excessive wear of the replaced joint by perhaps taking a buggy whilst playing golf, to stay on the easier ski runs and to restrict the number of games of tennis played during the week!

Patients who have had surface replacements have notoriously been involved in contact sport, judo and running, sometimes long distance. Although these are activities are possible, very little is known as to what the long term consequences are of taking part in very vigorous physical activity with a resurfacing joint replacement!

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