Can Shoeing Affect Fetlock Angle?

Background

Therapeutic application of orthopaedic horseshoes often aims to change hoof orientation, and thereby the alignment of the phalanges and the angulation of the fetlock joint. Based on this, the following biomechanics principle has been established by Denoix et al. as a basis for the use of orthopaedic horseshoes (Fig 1) [1-3]: A steeper orientation of the hoof causes an increased flexion of the distal interphalangeal joint (DIPJ) associated with less strain on the deep digital flexor tendon (DDFT). Simultaneously, a lowering of the middle and proximal phalanx occurs, causing an increased extension in the fetlock joint. This means a higher load on the suspensory apparatus. According

to this stated principle, relief of structures supporting the fetlock joint (suspensory ligament (SL), superficial digital flexor tendon (SDFT)) is achieved by lowering the hoof orientation causing less extension in the fetlock joint. However, practical observations showed that individual reactions related to orthopaedic shoeing to relieve the DDFT, SDFT and SL disagree with the assumption of general solutions to treat specific orthopaedic disorders.

Therefore, the aim of the current research was to examine what initial change in hoof angulation is necessary to have a significant effect on the fetlock joint angulation and the strain on the DDFT and SDFT in a larger population of live horses with different toe conformation under physiological conditions.

[...]