Hand-walking is an important part of suspensory ligament disease rehabilitation. | Photo: iStock

Suspensory ligament (SL) disease is one of the leading causes of poor performance in horses. Injury to this structure (which originates from the back of the fore and hind cannon bones, courses between the splint bones along the back of the cannon bone and divides into two branches that insert on the sesamoid bones) can be frustrating to manage. At a table topic forum during the 2015 American Association of Equine Practitioner’s Convention, held Dec. 5-9 in Las Vegas, Sue Dyson, MA, VetMB, PhD, from the Center for Equine Studies Animal Health Trust, in the United Kingdom, and Lane Easter, DVM, Dipl. ACVS, of Performance Equine Associates, in Oklahoma, discussed suspensory treatment options and ideas with a group of veterinarians.

Q: How many practitioners do surgery on chronic hind leg suspensory disease?

Upon being asked this question, one-third of the practitioners in the room raised their hands. Ultrasound is a useful diagnostic tool for suspensory injury, and if the veterinarian makes a positive diagnosis of SL disease, then he or she should consider surgery. Horses not considered surgical candidates are those with straight hind limb conformation or hyperextended rear fetlocks. Dyson pointed out that the presence of sacroiliac pain does not obviate surgery but might impact the prognosis. There is no point in waiting three months to go to surgery, she added. Together, a neurectomy (cutting the nerve) and fasciotomy (cutting the fascia to relieve pressure on the enlarged ligament) often produce the best results, said Dyson. Fasciotomy alone does not yield as good a result. With neurectomy alone, said Dyson, “We have seen an association between tightness of the fascia at surgery and the degree of lameness. We also have evidence of compressive nerve injury. Therefore, there is value in cutting the fascia along with neurectomy.” She noted that, because the suspensory ligament is anatomically related to the hock, surgery might alter the mechanical loading of the hock slightly and predispose the horse to low-grade lameness associated with hock pain. Veterinarians can managed this with pain-relieving medication.

Q: How many horses have bilateral surgery?

Many horses with hind limb suspensory disease are bilaterally (on both sides) lame. If the horse is only lame in one hind limb but the veterinarian identifies pathology via diagnostic tests in the nonlame hind limb, he or she should operate on both hind legs. It is important to do a comprehensive ultrasound exam of the hock and cannon region, including the flexor tendons and the entire suspensory ligament, from top to bottom. It is important not to overlook injury to another structure, said Dyson