The aim of this article is to study the relationship between tibia vara and external tibial torsion in adults. The following questions were asked: (1) what is the incidence of rotational deformity in patients with genu varum and (2) do patients who undergo correction of tibial torsion with genu varum have similar outcomes to those who undergo simple tibia vara correction? In this study, 69 patients (138 limbs) underwent bilateral proximal tibial osteotomy for the correction of genu varum. Patients with simple coronal plane deformity (varus alone) were treated with either a monolateral external fixator or a hexapod frame. Those with concomitant external tibial torsion were treated with circular external fixation. The primary outcome was the ability to achieve the desired correction of alignment in the coronal, sagittal, and axial planes. Secondary outcomes included a postoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) and a routine patient satisfaction questionnaire. The incidence of tibial torsion among the entire group of patients with bilateral tibia vara was 46% and overwhelmingly external in direction. The two groups had some significant differences in demographics with torsion patients tending to be younger and thinner. The final mechanical axis deviation and medial proximal tibial angle values for both groups did not differ significantly (p = 0.956). The postcorrection thigh-foot axis was not significantly different between the two groups (p = 0.666). Time to union was not significant (p > 0.999). KOOS was not different between the two groups in symptoms, pain, activities of daily living, and return to sport. There was a difference in the quality of life score between the two groups (p = 0.044). There was no difference between the two groups regarding the patient questionnaire. Based on the finding of this analysis, the incidence of rotational malalignment with genu varum is close to 50%. The recognition of this close association with external tibial torsion deformity may allow for further insights into the role of rotation in varus deformity-related knee pathology and treatment. Patients can expect nearly identical outcomes from this surgery.
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