The periosteum: its function reassessed.

A review of experimental work relating to the function of the periosteum, beginning with that of Macewen in 1912, is of special interest to clinicians. Macewen's failure to obtain new-bone formation following the subperiosteal removal of the radius was due to a technique that obliterated the space, an occurrence that is inevitable in total excision. The periosteum without an associated hematoma in contact with bone has no evident bone-forming properties. Except in avulsion fractures, the periosteum provides mechanical connection between the two bone fragments and is the vehicle for the revascularization of the contents of the periosteal tube. Loss of this continuity is one of the causes of fibrous union in avulsion fractures. In developing countries, delayed and unsatisfactory treatment of fractures provides valuable clinical information in the role of the periosteum. Destruction of the periosteum along with the bony shaft in extensive untreated osteomyelitis results in a missing segment of a major bone.