34th Annual Scientific Meeting proceedings

Therapeutic shoeing is a critical component of the rehabilitation process in horses following foot surgery. It requires a multifaceted approach that integrates veterinary expertise with specialist farriery. Therapeutic shoeing plays a key role in stabilising anatomical structures, managing mechanical forces, and promoting optimal healing conditions after both bone and soft tissue procedures. By modifying hoof biomechanics, enhancing support, and optimising limb alignment, shoeing strategies can reduce pain, improve locomotion, and shorten recovery time—facilitating a quicker return to controlled exercise and, ultimately, full athletic function.

The external impact force generated between the hoof and the ground is known as the ground reaction force (GRF). The magnitude of this force depends on the horse’s weight and speed of movement. GRF primarily acts to extend the distal interphalangeal joint (DIP), creating torque that is counterbalanced by the flexion moment generated by the deep digital flexor tendon (DDFT). This interaction is significant in therapeutic shoeing, as altering these forces can increase or decrease pressure on various structures within the hoof capsule. While standard steel shoes have minimal impact on GRF, they increase hoof impact and reduce hoof wall expansion.

Egg-bar shoes have been used to increase ground contact and distribute forces more evenly across the heels (2,3). These shoes provide caudal hoof support and reduce strain on the DDFT but concurrently increase strain on the suspensory ligament. Notably, they do not reduce the force exerted by the DDFT on the navicular bone (4). Egg-bar shoes are very useful for heel bulb lacerations or distal phalanx fractures. In cases of distal phalanx fractures, a high rim can be added to provide additional stability and support to the hoof. However, as egg-bar shoes restrict hoof expansion, prolonged use may lead to heel collapse.

Conversely, raising the heels by 6 degrees has been shown to reduce the force transmitted to the navicular bone by the DDFT by 24% (4), due to decreased DIP joint extension and a flatter DDFT angle around the navicular bone. Increased heel height also induces flexion of the DIP and proximal interphalangeal (PIP) joints and extension of the metacarpophalangeal joint (MCPJ). Both in vitro and in vivo studies demonstrate that heel wedges increase maximum flexion and reduce maximum extension of the PIP joint (5,6). Toe wedges, meanwhile, reduce strain on the superficial digital flexor tendon (SDFT) and suspensory ligament (SL), but increase strain on the accessory ligament of the DDFT and the DDFT itself.

Frog support graduate shoes are useful for treating damage or lesions of the navicular bone or DDFT due to solar penetration. They provide hoof stability and help relieve tension in the navicular/DDFT area. Different degrees of wedging can be used to raise the heels and make the horse more comfortable; these can be adjusted between shoeing cycles. Following metacarpophalangeal joint (MCPJ) or proximal interphalangeal joint (PIP) arthrodesis, caudal support should be provided to stabilize the MCPJ, but heel wedges may have the opposite effect. Heel elevation should be avoided after these surgeries, as it increases flexion of the PIP and extension of the MCPJ.

There remains a significant gap in veterinary knowledge regarding the clinical effects of shoeing and farriery in lame horses or those with hoof capsule pathologies. Most of the current research evaluates the biomechanical impact of shoeing in sound horses or in vivo models. While this research is valuable and helps guidance for shoeing decisions for specific conditions, its clinical applicability remains limited.

References

1. Roepstorff L, Johnston C, Drevemo S. In vivo and in vitro heel expansion in relation to shoeing and frog pressure. Equine Vet J Suppl. 2001;54–7.
2. Østblom LC, Lund C, Melsen F. Navicular bone disease: results of treatment using egg-bar shoeing technique. Equine Vet J. 1984;16:203–6.
3. Riemersma DJ, van den Bogert AJ, Jansen MO, et al. Influence of shoeing on ground reaction forces and tendon strains in the forelimbs of ponies. Equine Vet J. 1996;28:126–32.
4. Willemen MA, Savelberg HH, Barneveld A. The effect of orthopaedic shoeing on the force exerted by the deep digital flexor tendon on the navicular bone in horses. Equine Vet J. 1999;31:25–30.
5. Chateau H, Degueurce C, Jerbi H, et al. Normal three-dimensional behaviour of the metacarpophalangeal joint and the effect of uneven foot bearing. Equine Vet J Suppl. 2001;33:84–8.
6. Chateau H, Degueurce C, Denoix JM. Effects of 6-degree elevation of the heels on 3D kinematics of the distal portion of the forelimb in the walking horse. Equine Vet J. 2004;36:649–54.
7. Chateau H, Degueurce C, Denoix JM. Three-dimensional kinematics of the distal forelimb in horses.
8. Riemersma DJ, van den Bogert AJ, Jansen MO, et al. Influence of shoeing on ground reaction forces and tendon strains in the forelimbs of ponies. Equine Vet J. 1996;28:126–32.