Knee Arthritis

WHAT IS THE Knee JOINT?

The knee joint is a hinge joint between the bottom of your thigh bone (femur), and the top of your shin bone (tibia). The ends of these bones are both covered by a thin layer of articular cartilage. This is the smooth surface which allows your knee to move freely without friction. Inside the joint are two discs of fibrous cartilage called the meniscus, which act as a protective shock-absorber for the joint. The whole joint is surrounded by a layer of fibrous tissue called the knee capsule. This separates the joint from the surrounding muscles and tendons.

WHAT IS ARTHRITIS?

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Arthritis is a general term covering numerous conditions where the joint surface (cartilage) wears out. The most common form of knee arthritis is osteoarthritis. Osteoarthritis is a degenerative type of arthritis in which the cartilage in the knee joint gradually wears away over time. As the cartilage wears away, it becomes frayed and rough, and the normal joint space between the bones decreases. With time, all of the cartilage is lost and this leads to bone rubbing on bone. To make up for the lost cartilage, the damaged bones may start to grow bone spurs called osteophytes. Osteoarthritis develops slowly and the pain it causes worsens over time. As well as osteoarthritis there are many other less common forms of arthritis. These include:

  • Inflammatory arthritis - rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis

  • Post-traumatic (injury related) arthritis

  • Post-infection arthritis

  • Avascular necrosis

WHAT CAUSES ARTHRITIS?

Osteoarthritis has no single specific cause, but there are certain factors that may make you more likely to develop the disease. These include:

  • Increasing age

  • Family history of osteoarthritis

  • Previous injury to the knee joint

  • Obesity

Even if you do not have any of the risk factors listed above, you can still develop osteoarthritis.

WHAT ARE THE SYMPTOMS OF KNee ARTHRITIS?

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The main symptom of knee arthritis is pain in the knee joint. This may be felt mainly on one side of the joint, depending on which part is the most worn. Pain is usually worse with activity such as getting up from a chair, standing or walking. Pain at night with sleep disturbance is also common. You or others may notice that you limp when walking. As arthritis progresses, your knee joint also becomes stiff, and may make a grinding noise (crepitus) with movements. Your knees may become bowed as the cartilage wears away unevenly. Getting up from a low chair, kneeling or getting up from the ground can become difficult.

HOW IS KNEE ARTHRITiS DIAGNOSED?

Knee arthritis can usually be identified from your symptoms and a clinical examination. A standard x-ray of your knee joint is normally enough to confirm the diagnosis of arthritis. X-rays may show narrowing or loss of the joint space, thickening of the bone (sclerosis) and the formation of bone spurs (osteophytes) around the knee joint. Occasionally in very early arthritis an MRI scan is needed to identify cartilage damage.

WHAT IS THE non-surgiCAL TREATMENT FOR KNEE ARTHRITIS?

Although there is no medical cure for osteoarthritis, there are a number of treatment options that can help to relieve pain and improve mobility. The initial treatment for knee arthritis is non-surgical, and includes a number of simple measures which can help maintain your quality of life and activity levels. These include:

  • Keep fit and strengthen the muscles in your thigh and leg with regular exercise. If required, a physiotherapist can provide you with an individualised exercise programme.

  • Put less stress on your knee by switching from high-impact activities (like long walks, jogging or tennis) to lower impact activities (like swimming or cycling).

  • Losing weight can reduce stress on the knee joint, resulting in less pain and increased function.

  • Take regular simple pain relief medication such as paracetamol or anti-inflammatory medication such as ibuprofen, Voltaren or Celebrex. This can help you stay active and delay the need for surgery.

  • Using a cane or walking stick in the same hand as your arthritic knee can reduce the pressure in your knee when walking and decrease pain.

Are Stem cells an option?

There is currently no evidence that stem cell therapy is effective at restoring the worn cartilage in an arthritic knee. The use of stem cells is limited to treatment of small areas of cartilage damaged by injury, when the rest of the surrounding cartilage is normal. Some types of alternative therapy may help ease pain temporarily. These include:

  • Glucosamine, chondroitin or fish oil tablets. These can be obtained from most pharmacies. They do not rebuild cartilage, but may have an anti-inflammatory effect which could improve pain and swelling caused by arthritis.

  • Synvisc/ hyaluraunic acid injection. This is an injection of thick fluid into the knee designed to help lubricate the joint. It is not covered by most insurance policies and costs several hundred dollars. It can help ease pain for up to six months, but will not regrow cartilage in the knee. Hydrocortisone injection is just as effective, and much cheaper.

You may also have heard of platelet-rich plasma (PRP). This is made by spinning down your own blood to extract natural growth factors from the serum. Current evidence for the efficacy of PRP is poor.

WHAT IS THE SURGICAL TREATMENT FOR KNEE ARTHRITIS?

Once you have arthritis which is no longer responding to conservative treatment, you may well be a candidate for total knee replacement surgery. Knee replacement is a very effective operation and gives most people many years of free from pain. If your arthritis is confined to only part of your joint, there may be other surgical options such as partial knee replacement, patellofemoral (kneecap joint) replacement or osteotomy (bone realignment). Many factors need to be considered in choosing the right operation for you. Click the link to learn more about knee replacement.