Serum osteocalcin and total alkaline phosphatase levels as prognostic indicators in tibial shaft fractures.

Serum samples were obtained periodically from 50 adult patients with closed tibial shaft fractures. Total alkaline phosphatase activity was measured in all cases and osteocalcin activity was measured in 14 patients. Fractures produced by high-energy violence generally had lower values of osteocalcin activity. This could be due to depressed circulating vitamin K levels throughout the healing period in the former fractures. In addition, normally uniting fractures had generally higher values of osteocalcin activity compared with fractures exhibiting delayed union. This indicates depressed osteoblastic activity in slowly healing fractures. The results suggest that measurement of osteocalcin activity after fracture could provide a useful prognostic indicator. By contrast, total serum alkaline phosphatase activity was not significantly different between the injury groups and between the healing groups.