Prevalence of Individual Differences in Tibial Torsion: A CT-Based Study.

Abstract

To measure baseline bilateral tibial torsion in a cohort of uninjured patients to assess for a difference in torsion between sides. Consecutive bilateral lower extremity CT angiography scans from 229 patients without tibial or fibular pathology were collected and reviewed. Torsion of each tibia was measured by two independent reviewers, and individual differences in torsion were calculated. On average, patients have a 6.0° difference in tibial torsion between sides. A difference of greater than 10° was present in 18% of patients. Across the cohort of patients, the right tibia was on average 4.4° more externally rotated than the left. In patients with a greater than 5° difference, the right tibia was more externally rotated than the left in 85% of cases. Tibial torsion did not correlate with age or sex. Differences in tibial torsion are common and should be considered during intramedullary nailing of tibial fractures. When a difference in torsion is present, external torsion of the right tibia when compared with the left occurs predominantly. Prognostic level IV.