The knee joint is lined by articular cartilage, a specialised lining which allows smooth, painfree motion of the joint. Arthritis is a degeneration or wearing out of this lining which results in the bone ends rubbing on one another rather than the articular cartilage causing pain.
Types of Arthritis
Osteoarthritis: This form of arthritis can be due to normal ageing, or may develop as a result of another condition, past surgery or trauma. Heavy manual labour, obesity and a family history can predispose patients to osteoarthritis. The pain tends to be worse in the mornings and with vigorous activity.
Inflammatory Arthritis: The most common form is rheumatoid arthritis, an immune disorder resulting in inflammation of the synovial lining of the joint which releases chemicals and can subsequently damage the articular surface. This condition can affect any synovial joint in the body and is best treated medically by a rheumatologist. Knee replacement is only required when there is severe damage to the joint.
What are the symptoms?
- Pain – Usually of gradual onset but can be sudden. May be localised to one area in the joint or be all around the knee.
- Stiffness – It may be difficult to straighten or bend the knee
- Trouble walking – You may have a limp, grinding or clicking, or your joint may ‘give way’. These symptoms may be associated with limitation of walking due to either pain or fatigue
- Swelling – The inflammation might also make the joint feel hot and red.
- Deformity – The leg can change shape (become more bow legged or knock kneed)
How is it diagnosed?
Osteoarthritis is diagnosed on history, physical examination and X-ray. Physical examination will reveal pain on moving the joint and limitation of movement as well as osteophytes. X-rays will reveal narrowing of the joint space and often deformity of the bones and osteophytes. Blood tests are useful in inflammatory arthritis.
- Simple analgesia
- Anti-inflammatories supervised by local doctor
- Special medications for inflammatory arthritis
- Corticosteroid injections
- Weight loss
- Maintenance of fitness and muscle tone
- Use of a walking stick in the opposite hand to take weight off the knee
- Shoe inserts to absorb shock
- Glucosamine and chondroitin sulfate
- Hyaluronic acid injections
This is a minimally invasive surgical procedure in which a miniature telescope-like instrument is passed into the joint so that the surgeon can see the inside of the knee in great detail, and operate through just two small incisions. This can help in early arthritis especially with sudden onset of symptoms. Often there is an associated meniscal tear, or loose flaps of cartilage which can be removed. An arthroscopy is useful in a knee that is not bad enough to warrant a replacement.
This is an operation to cut the bone and realign it so that more weight is taken on the healthy part of the joint. It is particularly helpful in young active patients who are not suitable for a joint replacement.
This is indicated in well-localised lesions in young patients.
This can be either a partial or a full knee replacement depending on symptoms and X-ray signs.