Serum osteocalcin increases during fracture healing in elderly women with hip fracture

The purpose of this study was to define the bone metabolic properties during the postfracture period in elderly women with hip fracture. Osteocalcin (Oc), a marker of bone formation, was measured in 58 women with hip fracture (77 +/- 7 years) admitted to the hospital from their own homes. Serum samples were taken on average 5 h (range 1-21) from fracture and at follow-up, on average 4.6 months later. Comparison was made with 58 age-matched (79 +/- 5 years) women. Women with hip fracture had initially 30% lower Oc levels compared to the controls (p = 0.0001). The Oc level was independent of time elapsed from trauma, within 18 h, after which the level further decreased. At follow-up, Oc showed a 44% increase (p = 0.0001) and had reached the level of the controls, but not beyond it. A concomitant, but less marked increase was noted for alkaline phosphatase (ALP) (p = 0.0001). We conclude that although the bone formation, as assessed by Oc, is apparently lower in elderly women who sustain a hip fracture, the ability to induce a fracture response, with an increased bone turnover during fracture healing is intact. Subsequently, it is essential that a time perspective is applied, as the bone metabolic changes in patients having sustained a fracture are related to the time elapsed from fracture.