Recent studies have demonstrated that fracture healing normally takes
place under hypoxic conditions. The present study evaluated the effect of a
state of chronic systemic hypoxia on fracture healing in dogs. A
significant delay in fracture healing was demonstrated in the hypoxic
animals roentgenographically, histologically, and by strength-testing
criteria. A further reduction in the available oxygen supply below that
present during normal repair had an adverse effect on fracture healing.