Hip Replacement: The Facts

History
Hip replacements were first attempted towards the end of 1800’s with gold and ivory being used to replace the femoral head.    In the 1930’s Mr Philip Wiles tried to make a hip replacement out of metal at the Middlesex Hospital in London but it was not until after the Second World War that hip replacement surgery really took off.

Sir John Charnley, pioneer hip surgeonImage of Sir John Charnley "pioneer of total hip replacement in the U.K."

In Paris Professor Robert Judet and his brother designed a partial hip replacement to treat hip fractures whilst in Norwich Mr McKee and Mr Watson-Farrer and in Manchester Professor John Charnley also devised their own hip replacements.  Their results, although not perfect, in reality became the first generation of modern hip replacements with further advances in time being made by Professor Muller from Switzerland and Professor Ling in Exeter.

In the United Kingdom over 60,000 primary (first time) hip replacements are now performed every year.   The overall success of this major operation is about 95 - 96%.

Indications
The main reasons for having a hip replacement are osteoarthritis, (wear and tear), of the hip joint limiting the patients’ quality of life due to pain and loss of independence and mobility.   Sometimes ‘hip replacements’ are also performed for inflammatory arthritis, (such as rheumatoid arthritis) and for fractures and less commonly for cancer. The operation normally takes 1 - 2 hours with most patients being in hospital for 5 days.

Illustration of a Normal Hip. Please click here to enlarge this image. Diseased Hip with Roughened Ball and Socket Joint. Please click here to enlarge this image.
Please click the illustrations above to enlarge them.

X-ray Image of an Arthritic Hip & a Normal Hip
An Arthritic Hip and a Normal Hip X-ray.


A Modern Cementless Total Hip Replacement Post-Operative X-Ray.

Implant Design
Mr Charnley uses both cemented fixation and cementless fixation.  In both of these cases the upper thigh bone (femur) is replaced by a metal ball on a metal stem inserted into the marrow cavity of the bone.  If the bone is strong, then a “press fit” can be achieved with a biological calcium crystal based coating.  Where the marrow is poor then antibiotic loaded cement is used as a grout.

The hip socket (acetabulum) may also be cemented or cementless and the ball articulates usually with a plastic like material – a high density polyethylene.

Illustration of a Replaced Hip. Please click here to enlarge this image.
Artists Impression Of A Cemented Hip Replacement, The Green Ink Representing The Cement.
Please click here to enlarge the image.

In younger and very active patients ceramic heads or metal on metal articulations may be used.

The cementless system Mr Charnley uses is the Corail design that has been in clinical use for twenty years with excellent results from the United Kingdom, Scandinavia and France where it was originally designed.  A Trilogy acetabular shell is his preferred metal acetabular liner.


Hip socket component for insertion without cement, the magnified image, showing bone cells growing onto the roughened surface for secondary anchorage.


A cementless femoral component with bio-active surface (Hydroxyapetite) and a ceramic modular head.

When Mr Charnley uses a cemented hip it is a standard hip replacement called the CPT (Collarless Polished Tapered) which was designed by Professor Ling and has been available for almost twenty years.

CPT Hip Replacment
Collarless Polished Tapered Hip Replacement.

The results of this hip replacement are equal to, if not perhaps slightly better, than many other standard designs.  Research at the Avon Orthopaedic Centre in Bristol, by Mr Gordon Bannister, Secretary of the European Hip Society, has revealed very good results with this hip prosthesis and excellent results are also reported in the Danish Hip Registry.

The performance of the hip replacement is also being studied closely by several centres in the United Kingdom with an independent assessment being performed by the Professorial Orthopaedic Surgery Department of the University of Dundee.  

Mr Charnley likes to follow up the joint replacements performed by himself and his team on a regular basis.

ZCA Cup routinely used in hip replacement surgery.
ZCA Cup Replacement used in Cemented Hip Replacement Surgery.

Benefits
The main reason for any patient having a hip replacement performed is to rid them of their arthritic pain.    In doing so unless multiple joints are affected by arthritis, this should lead to an improvement in an individual’s mobility and quality of life.   Indeed patients having had a satisfactory hip replacement believe their quality of life is improved as much as a patient having coronary artery by-pass for heart attacks or a renal transplant for kidney disease!

Complications
The average life span of all hip designs is about a decade.

As with any operation there are acknowledged risks.   Most patients are worried about their anaesthetic but modern day anaesthesia is extremely successful with rarely patients not waking up after their anaesthetic, (perhaps a 1 in a million risk).  Patients in their 8th decade do have more pre-existing medical problems than younger patients and have thus a raised risk of non orthopaedic post operative medical problems and need to be in good health to consider hip replacement.

Other risks associated with the surgery itself are infection from bacterial organisms and to reduce this Mr Charnley uses antibiotics around the time of surgery as well as using bone cement with antibiotics in it.   There is still a chance of one or two patients in every hundred having this complication.

Dislocation, (the ball coming out of the socket), does occur with hip surgery with a reported frequency of 1 - 9%.   Mr Charnley uses an incision which has the lowest reported rate of dislocation to try and minimise this problem.

Blood clots in the legs and on the lungs (thrombo-embolism) is also reported in particular in those patients who smoke.   It is advisable to give up for at least 6 weeks before the operation, if not for ever, before a hip replacement procedure.

There is a remote chance of damage to the nerves and arteries around the hip (less than 1 in 100), more so with those hips that have had previous surgery or are of a rather abnormal shape.

Fractures around the time of implant insertion, (peri prosthetic fractures) may occur with a frequency of 1%.

Finally following a hip replacement the surgeons performing the operation try and balance the leg lengths of the affected and unaffected sides but this is limited by the more important goals of a stable joint replacement and leg length discrepancies can be satisfactorily treated with orthotic aids.

The Post-Operative Period
Your hip surgery will be performed by an experienced team of surgeons, nurses, physiotherapists and occupational therapists.   The whole team will try and help you get over the post-operative period with advice about dos and don’ts (see additional information). 

You will normally be sent home on a pair of crutches once you are safe and not before.   The team are happy to give additional information regarding return to work, driving and sexual intercourse.

Self-Help
Patients can help themselves by preparing for surgery.  A visit to a physiotherapist or osteopath may enable patients to learn muscle strengthening exercises, which will speed up there rehabilitation.  In addition, stopping smoking will reduce the risk of thrombosis and a healthy diet with vitamins and zinc may also help wound healing.

Training, Education and Research
Mr Charnley and his surgical team perform over 200 hip replacements and partial hip replacements, (hemi-arthroplasties), per year. These are both for various types of arthritis and for fractures around the hip.

The majority of the surgery is performed by Mr Charnley himself, but also by experienced staff grade surgeons plus higher surgical trainees. These latter surgeons will have all been personally trained and supervised by Mr Charnley and by other hip surgeons on their training schemes.

All illustrations on this page are acknowledged and are supplied for patient information by Schering-Plough/Doctor Direct Ltd.

This page was last updated on 06/Mar/2012