Ligament Inflammation in Horses: Consider Bone Supplements for Layups

The long layup required for healing soft tissue injuries demands patience as well as modified management strategies. Further, the prognosis for these patients—the chances they will return to their previous level of performance—can be guarded. What can be done during convalescence to encourage a sound return to performance?

Strategic nutritional supplementation supports skeletal health during stall or paddock confinement and will help maintain optimal bone mineralization during layup. “Triacton, a supplement from Kentucky Equine Research, contains a carefully formulated mixture of minerals and vitamins scientifically proven to increase bone mineral density and bone area. This product is suitable for building strong bone in both performance and growing horses, and is particularly beneficial for preventing bone demineralization during stall rest,” advised Peter Huntington, B.V.Sc., M.A.C.V.Sc., director of nutrition at Kentucky Equine Research.

Injuries to the distal sesamoidean ligaments often require long layups. Three paired ligaments and one straight ligament connect the sesamoid bones of the fetlocks to the long pastern bones in all four limbs. The distal sesamoidean ligaments may be regarded as a continuation of the suspensory ligament. This ligamentous assemblage supports the fetlock and diminishes concussion.

With improved imaging techniques, especially ultrasound, veterinarians routinely identify subtle lesions in the distal sesamoidean ligaments. Because of this precise detection, horses can receive targeted treatment that may allow them to return to work more quickly.

In a recent retrospective study, data were extracted from case files involving horses with injuries to the distal sesamoidean ligaments. In addition to details about each horse’s injury, the files revealed typical management strategies:

• Strict stall rest, usually 30-60 days;
• Small paddock turnout permitted for 4-6 months after stall rest ended;
• Initial exercise implemented and involved hand-walking that gradually reached a maximum of 45-60 minutes per day for 30-60 days;
• If sound, a ridden exercise program starting at a walk that gradually proceeds to the trot and canter depending on the patient’s progress.

“Because bone responds to workload, it’s a use it or lose it situation. When horses are confined to stalls, they rapidly lose bone mineral density and strength,” Huntington said.

According to Huntington, studies report losses of 15% bone mineralization after just two weeks of stall rest, with greater amounts of bone loss measured after four to eight weeks of absolute confinement. In contrast, when the horse is placed back into work, some speed work is required to help rebuild bone. This rebuilding occurs at a much slower rate than demineralization, he said.

“For this reason, using a supplement like Triacton will help prevent severe loss of bone mineral density during rest and also improve remineralization when the horse is back in work,” Huntington explained.

Even with strict exercise restriction and slow return to work, the prognosis for horses with injured distal sesamoidean ligaments was grave. Only 55% returned to soundness, and 31% returned to their intended use. Poor outcomes associated with certain soft-tissue injuries explain why so many research hours have been spent trying to improve tendon and ligament healing. Research on these techniques, such as regenerative medicine involving stem cells and platelet products, as well as laser therapy, continues to evolve.

^*Hawkins, A., L. O’Leary, D. Bolt, A. Fiske-Johnson, D. Berner, and R. Smith. 2021. Retrospective analysis of oblique and straight distal sesamoidean ligament desmitis in 52 horses. Equine Veterinary Journal doi:10.1111/evj.13438.