Osteoarthritis (arthrosis) is a chronic, progressive joint disease characterised by damage to the hyaline joint cartilage and secondary changes in bone, joint capsule, ligaments and muscles.
Typical complaints are load-dependent pain, start-up pain after rest and increasing restriction of movement. Imaging may show joint-space narrowing, subchondral sclerosis, osteophytes and subchondral cysts. Risk factors include age, mechanical overload, malalignment, trauma and excess weight. Stages are classified clinically and radiologically (e.g. Kellgren-Lawrence).