A comparison of three methods of measuring tibial torsion in children with myelomeningocele and normally developing children.

Abnormal tibial torsion is a common pediatric problem, and there are many existing measurement methods. The purpose of this study was to compare three methods of measuring tibial torsion for its evaluation: computed tomography, physical examination, and motion capture. Twenty healthy children and 20 children with myelomeningocele underwent measures of tibial torsion bilaterally. Measurements were compared using correlation and Bland-Altman plots of the difference between measurements. All three measurements were moderately correlated in controls (r ≥ 0.49, P ≤ 0.002) and in patients (r ≥ 0.51, P ≤ 0.001). In controls, the motion capture measurements were on average 2° more lateral than the clinical measurements whereas motion capture and clinical measurements were 13° and 15° more medial than CT measurements, respectively. Similarly for patients, motion capture measurements were on average 5° more medial than clinical measurements, and motion capture and clinical measurements were 26° and 22° more medial than CT measurements. The approximate 20° difference between the clinical or motion capture measures and the CT measure suggests that clinical evaluation identifies different axes than those defined based on skeletal anatomy. Clinical or motion capture methods may be used in lieu of imaging methods for measuring tibial torsion with the knowledge that these methods provide less lateral measurements than measurements obtained using CT. Clin. Anat. :1043-1048, 2017.