Frequently Asked Questions

Questions about Hip and Knee Replaceement

When should I consider a hip or knee replacement?
What type of hip replacement should I have?
What about Hip Resurfacing?
How long will my hip/knee replacement last?
Can my hip be re-done if it fails?
What are the possible complications of hip/knee replacement surgery?
What type of anaesthetic is available?
What can I expect from my hip/knee replacement?
Will I need a blood transfusion?
How long will I take to recover after my operation?
What precautions do I need to take following hip replacement surgery?


1. When should I consider a hip or knee replacement?

Hip or knee replacement is indicated when pain and/or associated disability is significantly interfering with day to day life and is no longer adequately controlled by non-surgical means such as pain killers, life-style modification, weight loss etc. Common good indicators are when pain is present all the time and pain killers make no difference, particularly if pain is waking you up at night.

Unacceptable disability varies from person to person, and is best judged on a case by case basis.


2. What type of hip replacement should I have?

There are many different types of hip replacement available; they vary in a number of ways:

The materials they are made of, the way they are fixed within the body and the overall design concept. Of more importance, to the type of hip replacement is the quality of the surgical procedure itself.

For the majority of people in the post retirement age group a well performed cemented hip replacement with a metal ball and a plastic socket is regarded as the gold standard and has a greater than 90% success rate.

For the younger patient with a longer potential life span and higher activity levels, then a hard bearing surface made of either ceramic on ceramic or metal on metal will probably last longer.

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3. What about Hip Resurfacing?

Hip Resurfacing, commonly known as the Birmingham hip, has been a popular choice over the last 10 - 15 years. It is, in fact, simply another form of hip replacement. However, it differs from more conventional hip replacements in that the ball of the femur (thigh bone) is not removed; instead it is reshaped and a metal surface cemented on to the top. The socket is made of solid metal.

The perceived advantages of Hip Resurfacing are that it is less likely to dislocate because it has a bigger ball than a standard joint replacement. Should it fail in the future, revision surgery is technically easier as there is no stem inside the femur. However, there have been a number of reported problems with Hip Resurfacing recently related to complications associated with generation of metal debris. Current advice is that this prosthesis is best reserved for the very active young male patient.

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4. How long will my hip/knee replacement last?

Sadly there is no such thing as a guaranteed perfect joint replacement; however, many follow up studies have shown that more than 90% of people are extremely satisfied with their joint replacement. The expectation is that at least 95% of hip/knee replacements will last for 10 years and the majority will go on performing satisfactorily up to 20 years and many joint replacements will last much longer than this.

Joint replacements can fail at any time for a variety of different reasons such as infection, loosening of the replacement within the body, wear of the socket, fracture of the bone around the replacement or, rarely, breakage of the replacement itself.

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5. Can my hip be re-done if it fails?

The majority of failed joint replacements can be revised at least once and sometimes several times more provided you are medically fit for surgery and there is sufficient structural bone available and symptoms warrant such major surgery.

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6. What are the possible complications of hip/knee replacement surgery?

Approximately 1 in 20 people may develop a complication associated with their operation, fortunately most of these are relatively minor and self limiting.

Complications related to hip replacement apart from general anaesthetic complications include the following:

  • Infection (less than 1%)
  • Dislocation (less than 1%)
  • Fracture of the femur
  • Nerve damage (less than 1%)
  • Deep vein thrombosis
  • Pulmonary embolism
  • Differences in leg length (up to 1cm)
  • Chronic scar pain

Complications related to knee replacement include the following:

  • Infection (less than 1%)
  • Deep vein thrombosis
  • Pulmonary embolism
  • Stiffness in the knee (inability to regain full range of movement)
  • Chronic scar pain
  • Fracture
  • Nerve damage

It is important to remember that these are major operations and apart from the complications described above they can be associated with other difficulties such as bowel and urinary tract problems. Patients with mental impairment can also be affected.

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7. What type of anaesthetic is available?

Hip or knee replacement can be carried out either with a general anaesthetic or with an epidural anaesthetic. For patients' with chronic chest problems then an epidural is strongly recommended, otherwise it is a decision based upon discussion between the anaesthetist and the patient as to personal preference.

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8. What can I expect from my hip/knee replacement?

Following a total hip replacement:

The primary objective of a hip replacement is to relieve pain. This will allow you to get back to living hopefully a normal day to day life, being able to enjoy outdoor activities such as golf, swimming, cycling and walking etc. Controlled downhill skiing is permitted, although off piste skiing would be ill advised. Very active people with a joint replacement will sometimes find that the hip/knee will ache after very heavy use but this will usually settle down with appropriate rest.

Following a total knee replacement:

The patient should have much less pain than before their surgery and should be much more mobile; however, some patients' still find it difficult to kneel because of the scar on the front of the knee and there is usually an area of numbness on the outside of the knee which may last for many months. The knee will also be swollen for several months following surgery but this varies from individual to individual.

All joint replacements can potentially make a noise, 3% of ceramic on ceramic hip replacements can occasionally squeak and a proportion of knee replacements can make a knocking sound. This is nothing to worry about and does not require any intervention.

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9. Will I need a blood transfusion?

Although blood transfusion can be a life saving measure where appropriate, it has become increasingly recognised that there are potential dangers associated with its use and therefore wherever possible it is now avoided with less than 1 in 20 patients requiring a transfusion. Wherever possible any anaemia present prior to the operation is corrected by a prescription of iron supplement and in a small number of individuals the use of a Erythropoietin. As a result of the blood loss associated with surgery some patients feel quite tired for 2 - 3 weeks until their haemoglobin levels have recovered.

For patients undergoing re-do hip replacement surgery we use a cell salvage machine which allows us to recycle the patients' own blood back to the patient.

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10. How long will I take to recover after my operation?

Patients having an uncomplicated hip replacement will be in hospital for anywhere between 2 - 5 days. By the time you go home from hospital you will be able to walk with the aid of crutches or sticks and be able to climb stairs and self care.

By review at 6 weeks, most people have dispensed with their walking aids and are walking comfortably.

Recovery following knee replacement takes longer and requires more active exercises to stretch the muscles and may require additional physiotherapy support.

Uncomplicated hip replacement patients do not normally require any additional physiotherapy other than exercise advice following discharge from hospital.

Patients who have undergone more complicated procedures may be required to protect weight bearing with crutches for 2 - 3 months following surgery.

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11. What precautions do I need to take following hip replacement surgery?

The main restriction following hip replacement is no driving for 6 weeks. There is evidence to show that reaction time is reduced within this period of time, increasing the risk to other road users. If it is a left hip and the patient has an automatic car then this time may be reduced. Excessively low seats should be avoided and where possible patients should preferably sleep on their back.