Veterinary advice should be sought before applying any treatment or vaccine.

Collateral Ligament Injury

Collateral ligament (CoL) injuries can occur in the tarsus (hock), elbow, and stifle. Horses will present with differing clinical signs depending on the location and severity of the injury.

CoL injuries to the Stifle: CoL injuries of the stifle occur most frequently in performance horses that jump (eventers, show jumpers, steeplechasers and hunters) or those that participate in disciplines with sudden stops or turns (barrel racing and polo). The medial CoL attaches to the medial meniscus (MM) at the joint space. Injuries to the medial CoL are more common in horses and may be associated with other soft tissue injuries within the stifle. Injuries to the medial CoL may be occur in acute or chronic form. The acute form usually occurs immediately following a traumatic event or fall, in which the horse usually presents with an acute onset of severe lameness. When injuries are chronic in nature, horses usually present with mild lameness, decreased stride length, and toe dragging on the affected side. There may also be varying amounts of soft tissue swelling and pain present.
CoL injuries to the Tarsus: The CoL of the hock consist of long and short groups medially and laterally that run at almost ninety degrees to each other, providing significant stability in a wide range of positions. Affected horses usually present with hindlimb lameness of variable severity that gets worse with exercise. There may also be swelling, thickening and pain of the soft tissues surrounding the affected area.
CoL injury to the Elbow: Horses present with a variable degree of lameness, but it is typically severe in the acute stages. The resultant lameness after this acute phase is dependent upon the degree of injury to the region if the elbow is destabilized.

Symptoms

Poor performance

Chronic or acute rear limb lameness

Lameness

Lameness worsens with exercise

Swelling, thickening and pain

Shortened stride length

Toe dragging

Diagnosis

History
Clinical Signs
Physical exam
Lameness exam
Radiographs
Ultrasound
Nuclear scintigraphy
MRI

Support

Therapies

Therapies	Details
Stall rest	The length of time needed and rehabilitation exercises are different for each horse, however the typical length of time is about 4-8 weeks, followed by a gradual increase in handwalking for 8-12 weeks; however this depends on the location and extent of the injury, use of the horse, and healing status of the injury. Progress of healing needs to be checked periodically with periodic ultrasound examinations. Depending on accessibility to various rehabilitation therapies, veterinarians may recommend the addition of swimming therapy such as aquatic treadmills (aqua tread).
Systemic NSAIDs, hydrotherapy, and sweat bandage wraps	often used during initial healing.
Polysulfated glycosaminoglycans
Intra-articular anti-inflammatory therapy (hyaluronic acid and/or corticosteroids)
Extracorporeal shock wave therapy
Regenerative therapies	Bone marrow derived mesenchymal stem cells, Platelet Rich Plasma (PRP) therapy, IRAP® (Interleukin-1 Receptor Agonist Protein)
Recheck ultrasound examinations	Performed every 6 to 9 months to assess healing status.

Prevention

Proper shoeing
Avoidance of poor or slippery footing while turned out in the pasture
Not placing the horse in show classes beyond their level of ability too soon
Properly condition horse

Prognosis

Prognosis varies significantly with the degree of severity of the injury. Horses competing at high levels have a guarded prognosis for full return to athletic use.