Ankle Alignment on Lateral Radiographs. Part 1: Sensitivity of Measures to Perturbations of Ankle Positioning

Abstract

Background-In ankles with end-stage osteoarthritis or with total ankle replacement (TAR), radiographic landmarks based on joint surface morphology are usually obscured and thus inadequate for radiographic measurement. Furthermore, because of difficulty in reproducibly positioning the ankle for a standing radiograph, any radiographic measure to accurately describe ankle alignment needs to tolerate perturbations of ankle positioning in clinical radiographs. To identify a radiographic measure of antero-posterior (AP) tibial-talar alignment that meets those requirements, three candidate measures were compared by means of sensitivity to perturbations of ankle positioning.

Frontal and lateral characteristics of the osseous configuration in chronic ankle instability

“…In CAI, this sliding is not physiological anymore because of the damaged ligaments, which produces abnormal kinematics, increased loading and consequently accelerated degeneration 14 16. An eccentric position of the talus under the tibia therefore leads to increased stress, accelerated rates of degeneration and consequently ankle osteoarthritis 17. The anterior position of the talar centre of rotation to the tibial axis explains why CAI is leading to ankle osteoarthritis over an average time of 34 years 16.…”

The effect of posture on the osseous relations in the foot

“…Already in 1967 Hlavac demonstrated that positioning of the foot in neutral, supinated, and pronated position alters the osseous relationships within the foot on radiographs [11,19]. Since then, other studies supported the importance of the posture and positioning of the foot [20][21][22]. X-rays are therefore often taken at the base of gait (midstance phase of gait) [2,11,12], in which the weight is about equally divided over both feet.…”

Influence of Ankle Position and Radiographic Projection Angle on Measurement of Supramalleolar Alignment on the Anteroposterior and Hindfoot Alignment Views

“…Weight-bearing radiographs, in particular, are essential to evaluate concomitant foot and ankle deformities. 11,32,50,51 For this purpose, the medial distal tibial angle (MDTA) serves to quantify supramalleolar ankle alignment in the coronal plane. 4,49 The MDTA can be measured on the anteroposterior (AP) view as well as the hindfoot alignment view (HAV).…”