Blood flow and mineral deposition in canine tibial fractures

Measurement of 125I-labeled 4-iodoantipyrine (I-Ap) washout is a useful method to study changes in bone blood flow because it can demonstrate fine changes in flow, the tracer is not involved in tissue metabolism, and several measurements can be made in the same subject. In the tibiae of twenty-one adult dogs there was a significant (p smaller than 0.001) correlation between I-Ap washout and the deposition of 85Sr, suggesting that the uptake of 85Sr is related to blood flow. After fracture, blood flow at the fracture site reached a maximum on the tenth day and then progressively decreased, but was not back to control values at 112 days. In the proximal part of the diaphysis, away from the fracture site, flow reached a maximum at five to twenty-one days and then progressively decreased to normal.