Rheumatoid disease in the hip causes pain, limitation of movement and deformity. There is osteoporosis, loss of joint space and erosions which may progress to collapse of the upper quadrant of the femoral head with destruction of the upper lip or floor of the acetabulum, producing femoral head subluxation on to the ilium, or central protrusion (figure 13.1). Osteoporosis and bony collapse are aggravated by systemic corticosteroid therapy (figure 13.2). The rheumatoid hip loses movement early, in contradistinction to the rheumatoid knee. Apart from its weight-bearing function, for which stability is required, hip mobility in rheumatoid disease is important, as a stiff hip throws undue strain on other joints during active life and later increases nursing difficulties should the patient become chairbound.