An arthroplasty is a joint replacement, such as a total or partial knee replacement.

total knee replacement


In a total knee replacement, the whole of the ends of the femur and tibia are usually removed, and replaced with metal and plastic. The articulating side of the patella may also be replaced.

unicompartmental knee replacement


This is an example of a 'unicompartmental knee replacement' (a partial arthroplasty), where only one side of the joint has been replaced.



Why are arthroplasties performed?

Pain from arthritis is the main reason for considering an arthroplasty. By removing the damaged ends of the bone and replacing them with artificial materials the arthritic pain can be greatly reduced together with most deformity from the arthritic process.

The word 'arthro-plasty' means joint re-shaping, so the term includes all extents of knee replacement -

  • unicompartmental (or partial) knee replacement
  • total knee replacement
  • interpositional arthroplasty (eg unispacer) - this is not truly an arthroplasty but a replacement for a missing meniscus, to avoid damage to the joint itself.

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Arthroplasty and the concept of 'compartments'

From the point of view of joint replacement, the knee is considered to have three compartments, and implants may replace any or all of them. These include the two tibio-femoral compartments and the patello-femoral compartment.

What is the difference between partial and total knee replacement?

A total knee replacement replaces the whole articulation of femur and tibia - both sides - and very often the patella also. A partial knee replacement is indicated when the joint destruction affects only part of the joint. So, for example, the replacement may be of just one of the condyles of the femur and the part of the tibia it articulates with.

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How long does it take to recover from a knee replacement?

Every patient will be different, and age and fitness will be factors. Muscle weakness and contraction may delay recovery. Usually patients are encouraged to bear weight very early, but full recovery may take many months.

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What is the issue of age with knee replacement?

It is not so much actual age but biological age that affects decision-making. The key issue is that the artificial materials are subject to wear and tear, and most joint replacements only last for a decade or so and have to be replaced. So the surgeon avoids doing this procedure in the younger patient to avoid revision surgery.

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Are there alternatives to knee replacement?

Realignment osteotomy is very valuable in the younger patient to change the forces going through an arthritic joint. This will relieve the pain and may give the patient many years before an arthroplasty becomes necessary.

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Joint replacement
Knee replacement

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Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...

Arthroplasty technology -

Types of arthroplasty -

Arthroplasty complications -

Dr Lars BløndExpert view - 2017 - Why do some patients experience osteoarthritis pain before changes are evident on X-ray? - by Dr Lars Blønd (Knee Surgeon)

Dr (Mr) Kirti Moholkar2009 - Knee Replacement - course - by Dr (Mr) Kirti Moholkar (Knee Surgeon)



man reading book

eBook - Knee arthritis interventions when you are too young for a total knee replacement by Dr Sheila Strover (Clinical Editor)

Easy-to-follow eBook about what is available if you have knee arthritis and are too young for a knee replacement.

man reading book

eBook - Indications for partial knee replacement by Dr (Mr) Rishi Chana

This eBook discusses the situation when a partial knee replacement may be preferable for the patient with arthritis.