[Changes in the concept of fracture healing and callus formation]

Although the treatment of fractures has repeatedly been documented throughout history, little attention has been paid to the historical development of the understanding of fracture healing and callus formation in itself. In antiquity, the capability of bone to regenerate was doubted, and Galen attributed the consolidation of a bone fracture to a sap (succus ossificus) that came from the food ingested. Later, in the eighteenth century, a haughty debate broke out as to the seat of the organ that controlled the by now accepted process of new bone formation. While Duhamel du Monceau (1700-1781) believed the periosteum was responsible for the callus formation--this idea being based on his observations of trees--Albrecht von Haller (1708-1777) and his scholars and disciples ascribed this function to the succus ossificus and to the bone marrow. The studies on experimental fracture healing that began during the seventeenth century resulted in the eighteenth-century discovery of the complex processes involved in the formation of callus with the aid of madder staining. The conciliation of the two major schools of thought was finally brought about when in the nineteenth century both periosteal and endosteal callus formation were shown to occur. The anatomical reposition of the fractured components and the stable fixation through osteosynthesis led to a novelty of the twentieth century: callus-free healing of bone fractures. Based on key texts and their authors, the zigzag course taken by our understanding of bone fracture healing and callus formation is illustrated.