What is knee osteoarthritis?
Knee osteoarthritis is the most common type of osteoarthritis, and is a very common cause of disability in the UK.
The surfaces of the joint are covered with cartilage, which allows low friction movement, and the joint is stabilised with ligaments, tendons and muscles.
As the cartilage is worn aware (as seen in arthritis), the underlying bone becomes exposed, and bony spurs and cysts can form.
Causes of Knee Osteoarthritis
Deterioration of articular cartilage is the main problem associated with knee osteoarthritis. The condition can be caused by:
- previous knee injury
- repetitive strain on the knee
- fractures, ligament tear, and meniscal injury which can affect alignment and promote wear and tear
- genetics which make some people more likely to develop knee osteoarthritis
- problems with subchondral bone (the bone layer underneath cartilage)
Diagnosis of Knee Osteoarthritis
The diagnosis of osteoarthritis is made using the clinical history, physical examination and imaging, such as x-rays. Blood tests may be used if it is necessary to rule out other types of arthritis.
If more detailed imaging is needed, an MRI may be ordered. Arthroscopic knee surgery is another way to view the condition of the knee.
Symptoms of Knee Osteoarthritis
Knee osteoarthritis typically develops gradually over a period of years. The primary symptoms associated with knee osteoarthritis include:
- pain (mild, moderate, or severe)
- limited range of motion in the knee
- localized swelling
Pain is usually worse following activity, especially overuse of the affected knee. Stiffness can worsen after sitting for prolonged periods of time. As knee osteoarthritis progresses, symptoms generally become more severe. Pain can become continuous rather than only when weight-bearing.
Treatment of Knee Osteoarthritis
Unfortunately, it cannot be cured but there are treatments available to help manage the symptoms.
Medications , such as paracetamol and non-steroidal anti inflammatories are one way to treat it.
Steroid injections can also be used to reduce inflammation and improve symptoms.
Other ways to manage the symptoms of knee osteoarthritis include:
- Weight loss (normal weight people have a 20% risk of hip OA, overweight have 25% risk, and obese have 39% risk)
- Physiotherapy and exercise
- Assistive devices
- Knee brace or support
Surgery is appropriate for patients with knee osteoarthritis who have failed other more conservative treatment options. Surgical procedures include:
- arthroscopy – an arthroscope checks the condition of the articular cartilage
- osteotomy – realigns angles of the hip joint
- Total or partial knee resurfacing