Osteoarthritis of the knee. Coloured 3D computed tomography (CT) scan of the left knee of a 71-year-old patient with severe osteoarthritis affecting the femora-patellar surfaces (upper left) of the joint. Osteoarthritis (or arthrosis) is a common degenerative disease characterised by a loss of the cartilage that lines the joints between bones. This leads to pain, swelling and occasionally may result in the loss of function of the affected joint. No specific cure exists but symptoms may be relieved through analgesic drugs and physiotherapy. Joint-replacement surgery is used in some of the most severe cases.