Bone Quality in Paget's Disease of Bone.

Paget's disease of bone is produced by a localized increase in osteoclastic and osteoblastic activity which can progress slowly to involve an entire bone if untreated. A common feature is enlarged bones which are deformed, particularly in weight-bearing regions of the skeleton such as the lower extremity. Pathologic fractures may be a consequence, and nonunion of femoral fractures is not uncommon. Analyses of bone biopsies from patients with Paget's disease indicate that there is a lower, heterogeneous degree of bone mineralization and a younger tissue age than that found in control bone. Pagetic bone also has less resistance to plastic deformation and a straighter crack path than control bone.