Sensitivity of different measures of frontal plane alignment to medial and lateral joint space narrowing: From the osteoarthritis initiative

Compared to HKA, goniometry demonstrated poor diagnostic validity with respect to JSN. The new FTA measure, in contrast, represented a reasonable surrogate of radiographic disease severity (JSN). The new FTA measure was skewed in the varus direction when compared to HKA and more so in females. This requires cautious interpretation when measurements are related to previous studies.