[Size and localization of exposed bone surfaces in advanced degenerative changes of the femur head].

Area and localization of bone exposure are examined in 37 femoral heads being removed for total arthroplasties. Both are inhomogeneous and show no relation to the duration of clinical complaints nor the changing of stress following limitation of motion or contracture. There have been numerous descriptions of the stress on femoral heads and the location of degenerative cartilage disease in zones of more or less stress, however all theories can be verified or disproved by the types of localization of bone exposure described. The theory that loss of cartilage is not as much due to stress but to chemical alterations cannot be confirmed. A new theory including all observations or a schema of localization of progressive degenerative disease cannot be presented for the present.