Background: The purpose of the present study was to determine the
validity and reliability of using ultrasound to measure tibial and femoral
Methods: In vitro ultrasound measurements of torsion in 118 matched
dried tibiae and femora were compared with direct anatomical measurements with
use of simple regression. The second part of the study involved repeated in
vivo ultrasound measurements made on twenty adult limbs to determine the
clinical reliability of our methods.
Results: The in vitro ultrasound measurements of femoral and tibial
torsion were significantly related to the anatomical measurements (p <
0.001 for both). The inter-rater correlation coefficients between three
examiners were 0.84 for both the tibial and femoral measurements, and the
intra-rater correlation coefficients ranged from 0.86 to 0.98. The in vivo
measurements were similar to the in vitro measurements, and the intra-rater
correlation coefficients for repeated measures were 0.91 and 0.93 for femoral
and tibial torsion, respectively.
Conclusions: Ultrasound is a viable tool for measuring torsion of
the tibia and femur. In order to minimize measurement errors, the ultrasound
measurement should be used to calculate the predicted value of torsion with
use of the regression equation.
Clinical Relevance: Abnormal torsion in the tibia and femur have
been linked to osteoarthritis in the knee. Precise, safe, and quick
measurements of torsion are needed for clinical decision-making and for use in