Osteoarthritis of the knee

Diagrams representing osteoarthritis of various joints

What is osteoarthritis of the knee?

Osteoarthritis is a condition that affects your joints. The surfaces of the joints can become damaged. As a result the joint does not move as smooth as it should.

When joints develop osteoarthritic changes the cartilage that covers the bones becomes rougher and more irregular and thinner. The bone underneath the cartilage reacts by growing bigger which often results in bone spurs at the edges of the joint. The joint can become swollen. This is the result of an inflammatory process that is attempting to repair the damage.

The condition has different names and is sometimes referred to as osteoarthrosis as well as arthrosis and degenerative joint disease and commonly also wear and tear.

Knee Joint

What are the symptoms of osteoarthritis?

The symptoms of osteo arthritis include: Pain, stiffness, cracking noises or grinding sensation when the joint moves (crepitus), swelling. The knee may lock or give way.

Most people notice pain mostly when they are active. There is usually pain when you first start moving which then settles after a while, but this depends on the degree of osteoarthritis. Pain often is worse at the end of the day particularly if you have been active.

Pain can vary. Many people have good periods with relatively little pain followed by periods or days of more intense pain. The knee can have a swollen appearance. This is often due to fluid accumulation in the joint, but the knee can also look bigger due to osteophytes (bone spurs at the edges of the joint). Stiffness is variable, for some people the stiffness can cause major issues such a not being able to ride a bike or finding it difficult to walk stairs.

Who is most likely to develop osteoarthritis?

  • People that are older (>50 years of age) are more likely to get it
  • People that have had a major knee injury in the past
  • People who are overweight
  • People who have a family history of Osteo-arthritis
  • Previous joint damage due to inflammatory arthritis (for example rheumatoid arthritis)

What is the prognosis?

It is not possible to predict you how your arthritis would develop over time. In many cases osteoarthritis develops over a period of many years very gradually. In some cases it can progress quite rapidly in a period of less than 2 years.

Whilst osteoarthritis can be painful it generally does not cause severe disability. Once the cartilage has completely worn away which occurs in people with more severe degrees of osteoarthritis, this can cause deformity of the joint and weakness of muscles is a secondary result of this as well. All these would impact on mobility and pain levels.

Many people with osteoarthritis develop fluid collection at the back of the knee joint which is called a Baker’s cyst. It is basically part of the joint capsule there is naturally protecting the knee joint and keeping a small amount of joint fluid in the knee. Once the fluid production is increased this capsule can herniate backwards and that will cause a fluid collection (Baker’s cyst) at the back of the knee joint.

If this is quite big and painful it can be aspirated (fluid can be drawn off) and also steroid can be injected. Both these procedures are available here at the Sonoscope one stop shop clinic.

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Cortisone Injection knee

How is osteoarthritis diagnosed?

X-rays are helpful to identify osteoarthritic changes in joints. 

Osteoarthritis does not cause abnormal blood results and therefore blood tests in osteoarthritis do not have a role to play. 

What treatments are helpful for osteoarthritis?

Physiotherapy has a significant role to play in the management of osteoarthritis. A specific exercise programme may help to select the correct exercises making sure that the patient works at the correct intensity and not too intense or not intense enough. The physiotherapist will also be able to give lots of other advice in regards to day-to-day activities and modification that can be very helpful to manage this condition.


Some people can be experiencing high levels of pain making it difficult for them to function and to sleep without waking at night. Nonsteroidal anti-inflammatory drugs such as naproxen, ibuprofen and many others, can be helpful to reduce high levels of pain. Unfortunately these drugs can cause side effects and are not suitable for some people with certain pre-existing medical conditions. Please speak to your GP to discuss.

Injection Therapy

When exercise therapy in addition with appropriate medications do not provide enough pain relief cortisone injection therapy can be considered as a next step.

Evidence states that ultrasound guided steroid injections are much more accurate than unguided steroid injections, as the needle placement can be monitored under ultrasound guidance.

There is a significant body of research indicating that ultrasound guided injections are not only safer but they also give longer lasting pain relief.

This means that the benefits are experienced sooner and the beneficial effects such as pain relief last longer.

Steroid Injection Therapy

Steroid injections have been used to manage pain in people with osteoarthritis for many years. It can be very effective to quickly reduce high levels of pain for a period of time. However it is very important to understand that this is a temporary measure. It should be seen that the pain relief from these injections would allow people to engage with exercise therapy which might otherwise not be possible due to the high levels of pain.

People have to be very cautious with repeat steroid injections as they generally will decline in effectiveness if repeated frequently. Also ongoing steroid injections will eventually cause significant side-effects and this is therefore not recommended.


Generally speaking, the surgery is fairly invasive and involves either full or part knee joint replacement. Although there might be temporary benefit from an arthroscopic washout it generally lasts for months not much longer than a steroid or hyaluronic acid injection.

Knee joint replacement surgery is a relatively big procedure and people should consider the risks and potential complications of this surgery carefully. Also whilst it can be very effective the knee joint still is liable to deteriorate over time so therefore knee joint replacement surgery is not recommended for people who are relatively young as there will be a need to replace the joint after an average of 15 years following the first surgery.

Hyaluronic acid injections:

Hydaluronic acid injections are relatively new. They are a good alternative for steroid injections and are not associated with any significant side effects. The mechanism of action is that the hyaluronic acid, which is not a drug but a gel, provides a coat to the Joint surface which will make the joint surfaces more slippery and promote gliding. This in turn will reduce the irritation of the arthritic joint and reduce pain as well as swelling. This option is particularly beneficial for people who are concerned about side-effects from steroid injections or who have not had great benefit from steroid injections. Hyaluronic acid injections may not be beneficial for people with fairly advanced osteoarthritis.

Each case should be discussed with our expert team


Osteoarthritis is a degenerative condition. This means that this is a condition that has to be managed and cannot be healed. Exercise therapy is the mainstay of treatment. A healthy lifestyle with plenty of exercise and a healthy body weight will help to reduce strain on the arthritic knee.

Medications such as nonsteroidal drugs or other medications can be of help but should be discussed with the GP. Some pain medications can cause serious side-effects in certain people and therefore need to be carefully monitored.

Steroid injections can be helpful to alleviate significant pain that is not managed well with advice on exercises. Hyaluronic acid injections are a good alternative for selected patients. Surgery is only advisable if the other options are no longer viable and preferably would not be advised for younger people if at all possible.


Meet Rob - Our Specialist Physiotherapist/ Sonographer

Rob is a specialist Extended Scope Physiotherapist with more than 20 years experience in managing complex musculoskeletal conditions.

He uses diagnostic ultrasound as an extension of his clinical skills.  He is an interventional sonographer in a busy radiology department of a central London Foundation Trust Hospital .

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