Osteoarthritis of the knee. Coloured X-ray of a section through the right knee of a 70-year-old male patient with osteoarthritis affecting the patella (kneecap) and femur (thigh bone), showing the presence of patellar osteophytes. 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.