Introduction to osteoarthritis
Osteoarthritis is the most common form of arthritis, and a leading cause of disability worldwide. It is characterised by pathologic changes in joints (cartilage, bone, synovium) and periarticular structures (ligament, tendon, muscle, and periarticular fat) that lead to pain, stiffness, and functional impairment. Deterioration in quality of life is common due to the chronic physical and psychosocial impacts of the condition.
Osteoarthritis is more common in women than men, and its prevalence increases significantly with age; it is exceedingly rare in people younger than 30 years. Osteoarthritic radiographic changes are not always associated with symptoms. For example, one-third of individuals older than 45 years will have radiographic evidence of knee osteoarthritis, but fewer than half of these people will have symptoms of knee osteoarthritisJordan, 2007. Radiographic findings consistent with osteoarthritis are not an indication for management.
Osteoarthritis can be a primary or secondary disease process. Primary osteoarthritis is often hereditary and is more likely to present with involvement of 3 or more joints. Secondary osteoarthritis may occur following trauma to a joint that results in cartilage injury or joint instability (eg anterior cruciate ligament [ACL] rupture, ankle fracture), removal of cartilage (eg meniscectomy), connective tissue conditions causing chronic joint instability (eg Ehlers–Danlos syndrome, congenital dysplasia of the hips), inflammatory arthritis (eg rheumatoid arthritis, calcium pyrophosphate deposition), and joint infections.
Osteoarthritis can involve almost any joint but typically affects the hands (proximal interphalangeal [PIP], distal interphalangeal [DIP] and first carpometacarpal [CMC] joints), knees, hips, feet, and facet joints of the cervical and lumbar spine.
The disease course in an individual is unpredictable; it may be slow and progressive or can stabilise over time. Acute increases in pain and swelling can also occur.