Bilateral asymmetries in clinical measures of lower-extremity anatomic characteristics

To quantify side-to-side differences in lower-extremity anatomic characteristics, and to compare the magnitude of left-right differences with the measurement error for each variable.

: Descriptive.

Applied neuromechanics research laboratory.

One hundred healthy participants (50 male, 50 females).

One examiner measured 14 anatomic characteristics on the left and right lower extremities. The value on the left was subtracted from value on the right, and 68% (+/-1 SD) and 95% (+/-1.96 SD) confidence intervals were constructed around the mean differences, respectively. These values were compared with the examiner's absolute measurement error for each measure.

Total leg length, pelvic angle, hip anteversion, standing and supine quadriceps angle, tibiofemoral angle, knee laxity, genu recurvatum, femur and tibia length, tibial torsion, rearfoot angle, and navicular drop.

Left-right differences in pelvic angle, tibial torsion, and navicular drop exceeded the measurement error in more than 32% of the cases. Five to thirty-two percent of the cases had left-right differences exceeding the measurement error for hip anteversion, standing and supine quadriceps angle, tibiofemoral angle, knee laxity, genu recurvatum, and femur length. Asymmetries in limb length were not observed.

Bilateral asymmetries exist in many clinical alignment characteristics, indicating that measurements taken on one limb may not be representative of the contralateral limb. We recommend measuring both extremities when anatomic characteristics are included as part of preseason screenings and prospective study designs to ensure valid comparison.