Knee Osteoarthritis

Pathophysiology

Osteoarthritis is the most common form of arthritis and is one of the leading causes of pain and disability. It referrers to a clinical syndrome of joint pain accompanied by varying degrees of functional limitation and subsequent reduced quality of life.

There is often a poor link between changes visible on an x-ray and symptoms of osteoarthritis; minimal changes can be associated with a lot of pain, or modest structural changes to joints can occur with minimal accompanying symptoms.

Osteoarthritis is a condition that results from a loss of cartilage with subsequent remodelling of adjacent bone and subsequent inflammation. It is some of these changes in the joint structure that can then be seen on x-ray. It is a dynamic process that involves all joint tissues: the bones, cartilage, joint capsule, lubricating fluid and surrounding muscles.

Sometimes the altered joint structure compensates for the changes and does not cause pain. It’s when the natural repair process cannot compensate enough that the joint starts to become painful.

Symptoms

• Stiffness, generally worse in the morning for less than 30 minutes which improves with movement

• Reduced range of movement

• Functional restrictions e.g. walking, climbing stairs, standing still

• Activity related joint pain- may be felt on inside, outside or front of the knee

• May be swollen and this may be worse with increased activity

Management

• Activity modification

• Ice or heat

• Pain relief

• Walking aids

• Appropriate footwear which provides support

• Weight loss if overweight or obese (most people will notice an improvement in joint pain and function after losing 5% of their body weight)

• Physiotherapy including range of movement exercises and a graded strengthening programme

• Orthopaedic options- If pain and function is limiting or conservative measures for 6 months has failed then knee replacement surgery may be appropriate

Investigations

X-ray can assess the level of osteoarthritis