High‐Speed Fluoroscopy: A Novel Method for Dynamic Imaging of the Equine Foot

Abstract

Aims This study describes the distal limb kinematics including intra‐horse and inter‐horse variability, and variability between gaits in sound horses using high‐speed fluoroscopy which allows cineradiographic examination at speed. Methods Distal limb kinematics were collected at walk and trot from 6 sound horses using a high‐speed fluoroscopy system set over a force plate. The dorsal proximal interphalangeal joint (PIPJ) angle and the dorsal distal interphalangeal joint (DIPJ) angle were repeatedly measured at toe‐on, 25, 50 and 75% stance. Results The PIPJ and DIPJ showed overall extension through stance. The mean (± s.d.) range of motion (ROM) during stance of the PIPJ was 10 ± 3° (walk) and 9 ± 3° (trot) and for the DIPJ was 29 ± 5° (walk) and 27 ± 6° (trot) showing significant differences between strides, gaits and horses (P<0.001). Conclusions High‐speed fluoroscopy allows for kinematic assessment of the distal limb. The ROM of the PIPJ observed was similar to the literature whilst the ROM for DIPJ was less than previously reported. Practical significance Kinematic analysis allows investigation of forces acting on bones, joints, ligaments and tendons. This is of special interest in the foot as the most common site of forelimb lameness in the horse; however, kinematic analysis of the foot has to date been a challenge due to the presence of the hoof capsule. The described method allows reliable assessment of foot kinematics at different gaits and speeds, which can be used for future studies to assess the effectiveness of treatment and monitor disease progression. Ethical animal research Ethical approval was granted by the Royal Veterinary College Ethics Committee. Sources of funding: The Royal Veterinary College. Competing interests: None.