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

OBJECTIVES: To measure baseline bilateral tibial torsion in a cohort of uninjured patients to assess for a difference in torsion between sides. METHODS: 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. RESULTS: 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. DISCUSSION: 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. LEVEL OF EVIDENCE: Prognostic level IV.

Effects of different frequencies of transcranial magnetic stimulation (TMS) on the forced swim test model of depression in rats.

BACKGROUND: Repetitive transcranial magnetic stimulation has been demonstrated in humans as well as in animal models to have an antidepressant effect, but the optimal frequency of stimulation is not known. We examined this question in a rat model of depression. METHODS: Young male Sprague-Dawley rats were allocated to two placebo (restraint and sham transcranial magnetic stimulation), one active control (imipramine), and four transcranial magnetic stimulation groups at 1, 5, 15 and 25 Hz and 1000 stimuli each. The Porsolt Swim Test was performed on day 1 (experiment 1). In an extension (experiment 2), the treatments were repeated on days 2 through 5, and the Swim Test repeated on days 3, 5, and 7. RESULTS: After one treatment session, all transcranial magnetic stimulation groups had significantly reduced immobility times compared with sham stimulation (p =.000), but the higher frequencies (15 and 25 Hz) did not differ significantly from lower (1 and 5 Hz) frequencies. After three sessions, all transcranial magnetic stimulation groups were different from placebo, and the rapid transcranial magnetic stimulation groups had lower immobility times than the slow transcranial magnetic stimulation groups (p =.035). After five sessions, only 15- and 25-Hz groups were different from control, and on day 7, only the 25-Hz group had reduced immobility. There was an overall difference between fast and slow transcranial magnetic stimulation (p =.010), and 1 Hz was different from the other three transcranial magnetic stimulation conditions (p =.016). CONCLUSIONS: Repetitive transcranial magnetic stimulation reduces immobility time in the Forced Swim Test model of depression, suggesting an antidepressant effect, which is evident at a range (1-25 Hz) of frequencies. With repeated administration, the findings suggest that the antidepressant effect of the higher frequencies, as for imipramine, is likely to be sustained, although the model used for this (i.e., repeating the Swim Test) requires further validation.