What is knee osteoarthritis?
Osteoarthritis is the most common form of arthritis to affect the knee joint.
It is usually a slowly progressive disease in which the joint surface cartilage gradually wears away leading to a painful rubbing of worn bone-on-bone joint surfaces.
The key characteristics of osteoarthritis are:
1. Mild inflammation of the tissues in and around the joint.
2. Damage to the smooth joint cartilage that would normally allow the joint to move easily and without friction.
3. Bony growth developing around the edge of the joint (osteophytes).

What are the symptoms of knee osteoarthritis?

1. Pain.
2. Stiffness.
3. Hard swelling (caused by bony osteophytes).
4. Soft swelling (caused by fluid within the joint).
5. Crepitus, clicking, catching when moving the knee joint.
6. Change in alignment or inability to fully straighten leg.


What are the causes of knee osteoarthritis?

Osteoarthritis of the knee is associated with the following risk factors:
1. Age greater than 50.
2. Female.
3. A family history of osteoarthritis in a close family relative.
4. Previous joint problem such as a torn meniscus, torn cruciate ligament or previous fracture or bony injury.
5. Increased body weight.

How is knee osteoarthritis diagnosed?
Following examination of the knee an x-ray can be very useful to confirm the diagnosis. This x-ray is best often taken in a standing position (weight bearing) to show maximum loading of the knee at the time.



What are the treatment options for knee osteoarthritis?
A range of treatment options exist for knee osteoarthritis starting from simple conservative (non-surgical) methods through to surgical options.
The most appropriate options for your knee depend on the degree of symptoms that you are experiencing severity of your arthritis.

Painkillers can help make the knee more comfortable, they may allow you to get to sleep at night or they may allow you to exercise more easily on your knee joint.
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs tablets (such as ibuprofen) may be of benefit if inflammation is contributing to the pain and stiffness.
Non-steroidals can also be used as an anti-inflammatory cream or gel, which can be rubbed on to the painful knee in people that have difficulty taking non-steroidal anti-inflammatory tablets
Lifestyle modification
Examples of lifestyle modification would include weight loss or changing from an impact activity such as running to a non-impact activity such as swimming or cycling.
Gentle exercise can be of benefit in knee osteoarthritis as it may maintain the range of motion and flexibility, and strengthens the muscles in and around the knee joint.
Exercise in the form of non-impact activities such as swimming and cycling are more readily tolerated.
Supportive devices
Supportive devices such as a walking stick or a knee brace can often be beneficial in some individuals.

In those individuals where conservative (non-surgical) measures have been tried but have been unsuccessful then there may be a role for surgical intervention.
The most appropriate intervention varies on an individual-to-individual basis. It depends on the severity of symptoms and the pattern of knee osteoarthritis that you experience.

Arthroscopic surgery (keyhole surgery)

Arthroscopic surgery (keyhole surgery) can still be of benefit in some individuals with arthritis who have very specific symptoms such as a sharp ‘jaggy’ pain or a feeling of the knee ‘locking’ or ‘catching’. In contrast, it tends not to be of lasting benefit for the ‘dull toothache like’ constant pain that can be associated with knee osteoarthritis.

Microfracture is a keyhole procedure carried out at the time of knee arthroscopy where small holes are made in the worn joint surface. This allows healthy cells (stem cells) to come from the underlying bone marrow with the aim of providing a new smoother bearing surface. The microfracture procedure is best suited to smaller localised defects.

Cartilage grafting
Cartilage grafting and other newer procedures such as osteochondral grafting are options for localised cartilage defects.

Osteotomy or realignment surgery
Osteotomy or realignment surgery can either be either a high tibial osteotomy or a distal femoral osteotomy. These procedures are used in younger patients with specific patterns of osteoarthritis where their lower leg alignment is off.

The aim of the procedure is to realign the knee so that the weight is no longer passing through the painful worn section of the knee.

Osteotomy surgery for knee arthritis is more suited to the younger patient who wishes to remain active following knee arthritis surgery. It is only indicated in certain patterns of knee wear.
It is important to understand that the surgery is not a ‘quick fix’. There is a fairly long recovery period and time for the bone to heal following this surgery. It can be very successful in the younger patient with knee arthritis and is often thought of as buying time for the future with a knee that may ultimately require to come to knee replacement surgery.

Knee replacement surgery
A knee replacement can either be in the form of a total knee replacement (TKR) or a partial (half) knee replacement. In addition a patellofemoral joint (PFJ) replacement can be performed.

A knee replacement is a very good operation for treating knee pain; which is the main indication for carrying out the surgery. As a result of this you may also get an increased range of motion in the knee but this is not guaranteed.
Following knee replacement it is possible to exercise with non-impact activities such as swimming or cycling as well as walking. It is not designed for those people who may wish to run or do impact-type activities following the surgery.
A commonly quoted estimate for the life expectancy of a knee replacement is in the order of 15-20 years.

For more information on the risks and benefits of knee replacement surgery please see procedures section knee joint replacement.