Side view X-ray of the thoraco-lumbar spine of a 78-year-old female patient with staged lumbar osteoarthritis. 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. The scan also shows a compression fracture of the T12 vertebra, most likely caused by osteoporosis. Osteoporosis is a reduction in bone density, resulting in an increase in brittleness and a greater risk of fractures, particularly of the vertebrae and the head of the femur.