Knee Arthritis

Arthritis is a general term that describes a number of conditions that result in inflammation of a joint. There are several types of arthritis that affects the knee joint.

• Osteoarthritis is the most common form of knee arthritis.  It results from a gradual wearing away of the cartilage, the cushioning layer, that exists between the base of the thighbone (femur), the top of the shinbone (tibia) and the kneecap (patella).  This causes the two bones to rub against each other creating friction on movement. This causes pain and discomfort.
• Rheumatoid arthritis is an autoimmune disease that can damage and cause destruction of your joints.  It is the most common form of  inflammatory arthritis seen in our population  and often affects the large joints of the body including the knees.  In a joint affected by rheumatoid arthritis, inflammatory cells gather in the lining of the joint (synovium) and these cells can cause destruction of the cartilage, ligaments and bone.  Other causes of inflammatory arthritis include psoriatic arthritis, ankylosis spondylitis and systemic lupus erythematosus (SLE).
• Post-traumatic arthritis develops following injury or fracture to the knee joint and results in pain and inflammation in the joint.

Osteoarthritis

The cause of osteoarthritis remains unknown.  The risk of developing the disease is influenced by a number of factors such as age, gender and inherited traits that affect the shape and stability of your joints. Risk factors for developing knee osteoarthritis include:

• A previous knee injury
• Repetitive strain on the knee
• Abnormal alignment of the joint
• Exercise or sports generated stress placed on the knee joint
• Increasing age
• Being overweight
• Family history of osteoarthritis

Rheumatoid arthritis

In rheumatoid arthritis, the immune system attacks normal and health body tissue.  The reason for this is still unknown. A number of things may increase your risk of developing rheumatoid arthritis including your genes (family history), hormones (more common in women than men) and smoking.

Post-traumatic arthritis

Injury or fracture to the knee joint causes damage to the protective cartilage that lines your joint. This injury leads to increased forces and stresses being placed on your joint and results in inflammation and pain. This increases the likelihood of developing post traumatic arthritis.

All forms of knee arthritis are commonly associated similar symptoms, these include:

• Pain – with activity, rest or at night
• Knee stiffness
• Swelling of the knee
• The knee may lock, catch or give way
• There may be strange noises or sensations on movement of the joint which can be a result of the loose cartilage fragments that interfere with smooth movement of the knee
• Difficulty going up and down stairs or ramps
• Difficulty with your activities of daily living, such as putting on your shoes and socks
• Difficulty with walking

If you are experiencing the symptoms listed above, you should consult your doctor.

Your doctor will take a detailed history of your pain and other symptoms. A physical examination will also be undertaken to assess where your pain is, how swollen the knee is and how the knee moves. It is likely that your doctor will also examine your hip and back to ensure that your pain is not being referred from one of these areas.

If your doctor suspects knee arthritis is the cause of your symptoms, you will be referred for a knee x-ray. This is still the best test to determine how much damage has occurred to the cartilage and bone of the knee joint. Your doctor may send you for a magnetic resonance imaging (MRI) scan or computed tomography (CT) scan if there is any doubt as to what is causing your symptoms.

If Rheumatoid (or another inflammatory) arthritis is suspected, your doctor may arrange some blood tests to help confirm that diagnosis.

There is no cure for arthritis, however there are treatment options to increase mobility and relieve pain.

It is always useful to try non-surgical options to manage your symptoms before contemplating an operation.  Some useful options include:

• Lifestyle modifications and regular exercise
• Weight loss
• Reducing high-impact activities
• Physiotherapy
• Wearing a brace to support the knee
• Simple pain relief medication – paracetamol and over the counter non-steroidal anti-inflammatories (eg ibuprofen, voltaren etc).  These help to manage pain and reduce inflammation
• Natural products – including fish oil, glucosamine, chondroitin, turmeric, magnesium and others. 
• Stem Cells – Many centres claim that stem cells injected into the knee joint can result in an improvement in symptoms and healing of your arthritis.  There is currently NO evidence to support these claims.

Once your symptoms can no longer be managed with non-surgical treatment options and you are no longer able to undertake your usual daily activities comfortably, your doctor may recommend knee surgery. The type of surgery your doctor recommends will be determined in consultation with you.  Surgical options include:

• Arthroscopy: A minimally invasive key hole procedure that enables diagnosis and treatment of some knee conditions.  Often a knee arthroscopy can be useful if you have developed new mechanical symptoms in the knee (locking, catching or giving way).  An arthroscopy can remove loose cartilage or bone, trim a meniscus tears and remove inflamed tissue.
• Synovectomy:  This can be performed via key hole surgery or by a larger incision when the inflammation is more extensive.  It involves removing the inflamed joint lining.  It is not commonly performed as the medications used to treat rheumatoid (and other inflammatory) arthritis are often able to control this inflammation. 
• Osteotomy involves breaking and re-setting the long bones (femur or tibia) around the knee to realign the knee joint.  The aim of this procedure is to off-load the damaged part of the joint, shifting the load to an unaffected or healthy part of the knee.
• Knee replacement Surgery:  This is still considered the “gold standard” of treatment for patients with knee arthritis that is no longer responding to simple and non-operative measures.  It involves accurately removing only the damaged cartilage and bone of the affected joint and replacing it with a new artificial joint.