Tissue oxygen tension in externally stabilized tibial fractures in rabbits during normal healing and infection

Permanently implanted Silastic tonometers were used to measure average extracellular oxygen tension in the medullary cavity of osteotomized rabbit tibias stabilized with external pin fixation. During uncomplicated healing the baseline bone pO2 rose slowly with time from 10 to 20 mm Hg while during staphylococcal infection pO2 varied between 8 and 15 mm Hg and showed no correlation with the healing time. The maximal response of the bone pO2 to oxygen breathing correlated linearly with the healing time whether the osteotomy was infected or not. On the 42nd day the maximal pO2 during systemic hyperoxia was 85 mm Hg for the control bones, 42 mm Hg for the osteotomized bones, and 30 mm Hg for the infected osteotomized bones. The results indicate moderate bone tissue hypoxia during uncomplicated healing and more profound hypoxia during healing affected by infection.