Replacement knee surgery: pros and cons

If you would like to know about knee joint replacement operations - specifically, the advantages and disadvantages of knee joint replacement - the following article will interest you.

Replacement knee surgery involves substituting an injured, worn, or diseased knee joint with an artificial joint. It is a routine operation for knee damage, particularly when arthritis is involved. The medical term for a complete knee replacement is total knee arthroplasty.

This article on the subject of knee replacement surgery is written by Jackie Griffiths, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.

The knee joint is a hinge between the thigh and shin bones. It is covered with a smooth but tough tissue called cartilage which allows the bones to glide over each other easily. But if this shock-absorbing cartilage becomes thin or damaged, the bones start to rub together which causes pain and swelling. This can occur in a range of conditions but is most common among people with osteoarthritis.

Other conditions that may require knee replacement surgery include:

  • rheumatoid arthritis
  • haemophilia
  • gout
  • unusual bone growth (bone displasia)
  • blood supply problems causing bone in the knee joint to die (avascular necrosis)

Non-surgical treatments

Most people who undergo total knee replacement surgery are aged between 60 and 80 years old. Patients must be in good physical health to cope with a major operation and the rehabilitation afterwards. It is, therefore, recommended to try non-surgical options before having an operation. These include:

  • physiotherapy – to improve flexibility, mobility and strength
  • painkillers – to reduce pain and allow greater movement
  • anti-inflammatory drugs – to reduce swelling
  • steroid injections – to reduce pain and swelling
  • losing weight – to reduce strain on the knees

The procedure

Knee joint replacement operations are performed by an orthopaedic surgeon, usually under a general anaesthetic. The alternative is to have an epidural that completely blocks sensation in the leg and enables the patient to stay awake during the operation.

Once the anaesthetic has taken effect, the orthopaedic surgeon makes a single cut about 15-30cm down the front of the knee. The kneecap is moved to one side so the joint is accessible. The worn or damaged surfaces are removed from the thigh and shin bones, and the ends are shaped to fit the artificial knee.

A replacement joint is fitted over both bones. The back of the kneecap may also be fitted with an artificial cap, known as a patellar resurfacing. Once all the new parts are in place, the wound is closed with stitches, and covered with a dressing. The knee will also be bandaged to reduce swelling. The total procedure takes up to two hours.

Benefits of replacement knee surgery

Replacement knee surgical operations are very successful at relieving severe knee pain and improving mobility of the joint. In one study, 9 out of 10 people rated their artificial knee as ‘good’ or ‘excellent’ five years after having surgery. For these people, a replacement knee should last for 10-15 years or longer still.

The initial pain of knee replacement surgery improves after the first week, and usually disappears completely after three weeks. After six months, the new knee is straight, comfortable when walking, and can bend more than 90 degrees.

Negative effects of replacement knee surgery 


There are unwanted but usually temporary effects of successful knee replacement surgery. For instance, your knee will be sore when you move it and may remain swollen for up to three months. There will also be a scar over the front of the knee, and the knee may be temporarily, or permanently, numb.


The new knee joint is unlikely to be perfect; some difficulty in movement is to be expected even some time after surgery. Some people also report a clicking noise in the artificial joint when they walk. This is the sound of the prosthetic parts moving together.

A replacement knee cannot last forever and the joint will wear out or become loose from the bone after a number of years. Fewer than 9% of people need to have the artificial joint replacement within 1-5 years of the original surgery. The repeat process is more complicated and may not be as successful as the first.

Complications of replacement knee surgery

On rare occasions, unexpected complications can occur during or after knee replacement surgery. These include:

  • infection of the wound or joint
  • instability of the knee, requiring a second operation
  • the affected leg may be longer than before
  • nerve damage during surgery
  • scar tissue may restrict movement
  • dislocation of the kneecap
  • blood clots in the leg (deep vein thrombosis)

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Replacement knee surgery: pros and cons