Osteoarthritis (OA) is a non-infl ammatory disorder of synovial joints characterized by articular surface wear and formation of new bone (attempts at repair). It is also known as degenerative joint disease and characterized by joint pain, stiffness and swelling of joints. Osteoarthritis is the most common joint disease, affecting up to 85% of the population at some time in their lives. It is often asymptomatic and the true prevalence of symptomatic OA in the western world is around 20%.
Histologically the weight-bearing cartilage surface degenerates and eventually wears away completely, exposing the subchondral bone, which becomes eburnated. Cysts occur because of microfracture of the articular surface and new bone laid down (sclerosis) in the surrounding bone. Disorganized new bone is produced at the margins of joints (osteophytes) as the disease progresses. In addition to this, the synovial lining becomes thickened and inflamed, often producing excess synovial fluid (an effusion).
The presenting complaints of patients with osteoarthritis are variable. The patient is usually systemically well and complains of pain which is usually aching or burning in nature and localized to the joint but may be referred to the joint below. The history is often of gradually increasing, asymmetrical joint pain over several years, the level of which is variable but can be severe. The pain is worse after activity and relieved by rest, and as the disease progresses night pain can be a feature. Occasionally patients present with rapidly destructive OA, which can mimic a septic or inflammatory arthritis.
Other symptoms include swelling, deformity (bow legs—varus knee), stiffness and weakness (usually secondary to wasting). Patients will also complain they are unable to do certain activities, which may be recreational or more basic activities of daily living (for example, patients with severe osteoarthritis of the hip are unable to put on socks or cut their own toenails).
The examination begins
- Look for a limp, use of a stick and how reliant the patient is on relatives for simple tasks such as undressing for examination.
- Deformity may be obvious but also note previous scars, redness, swelling and wasting of muscles on inspection.
- Palpate for an effusion, joint line tenderness and crepitus (cracking noise can be heard in severe cases).
- The range of movement of the particular joint will be diminished and there may be fixed deformity.
- The joints above and below should be examined.
There is no cure for osteoarthritis and treatment is aimed at relieving pain and maintaining function. The treatment for osteoarthritis can be conservative or surgical.