I. The Clinical and Radiological Problem of Thin Bones

Abstract

Osteoporosis is a disorder characterised by a reduction in bone mass without any known change in its chemical composition. This disorder appears usually to affect trabecular bone in the first instance but, as we shall show, compact bone may also be involved. It is responsible for a great deal of backache and disability in elderly women, and probably accounts for the increasing incidence of fractures of the femoral neck and shaft with advancing age. The definition, diagnosis, treatment and possible prevention of this condition are therefore of some medical and social importance. Osteoporosis is commonly classified into idiopathic, post-menopausal and senile varieties. We find this classification unsatisfactory because it makes certain assumptions about the pathogenesis of the disease which are quite unproven and may in fact be incorrect (Nordin, 1960a). It is probably preferable to classify the condition on the following lines:— 1. Generalised osteoporosis. (a) Primary osteoporosis—cause unknown. (b) Secondary osteoporosis—associated with hyperthyroidism, Cushing's syndrome, diabetes, hyperparathyroidism, acromegaly. 2. Localised osteoporosis—associated with immobilisation, rheumatoid arthritis and trauma (Sudeck's atrophy). Osteomalacia is the adult form of rickets. The essential feature of this condition is a progressive fall in the mineral content of the bone rather than a diminution of bone mass. This is due not to the removal of mineral from the bone skeleton but to a failure of deposition of mineral in new bone and cartilage.