Computed tomography reformation in evaluation of fracture healing with metallic fixation: correlation with clinical outcome.

BACKGROUND: The amount of callous needed for fracture stability is typically estimated by a combination of radiographic and physical examinations. Computed tomography (CT) with sagittal and coronal reformations was performed to determine the amount of callous needed for fracture stability based on a quartile analysis of bony bridging of the circumference of the fracture site.
METHODS: All patients who received CT with sagittal and coronal reformations of a fractured tubular bone for the purpose of analyzing bony bridging over a 22-month period were retrospectively reviewed. The final analysis included 34 patients and a total of 47 examinations. Fractures were placed into one of four groups depending on the amount of cortical bridging of the circumference of the bone: group I, 0-24%, group II, 25-49%, group III, 50-74%, group IV, 75-100%. Clinical outcome was determined on the basis of fracture stability, with mean follow-up of approximately 62 weeks.
RESULTS: A statistically significant increase in clinical failure was found in patients with <25% bridging. A cut-point analysis revealed that 37.5% (6 of 16) of failures occurred among patients with <25% bony bridging, and only 9.7% (3 of 31) of failures occurred among patients with >25% bridging, corresponding to a Fisher's exact test p value of 0.045.
CONCLUSIONS: Patients with less than 25% bridging of the circumference of a tubular bone should be considered high risk for failure, indicating the need for continued protection of the site.