Know your fetlocks
The fetlock is a hardworking high motion hinge joint. It is the meeting point of the cannon bone proximal sesamoid bones and the long pastern bone and is subjected to large forces and stresses as the horse moves making it vulnerable to injury.
Fetlock facts
This joint is a complexity of ligaments. The collateral ligaments wrap around the the joint for stability while the suspensory ligament runs from the back of the cannon bone to the two sesamoid bones at the back of the fetlock. Further ligaments attach the sesamoid bones to each other. These together with the suspensory ligament are collectively known as the suspensory apparatus. The flexor tendons at the back of the leg help the fetlock joint out a little but it predominantly has the heavy job of supporting the limb during the weight bearing phase of movement.
Fetlock problems
Soft tissue injuries
These include damage to any of the ligaments which is known in veterinary terms as desmitis. Your vet will scan the joint using ultrasound or MRI to diagnose the problem.
Depending on the severity of the damage your vet may suggest some regenerative medicine options together with rest and rehabilitation and a slow return to exercise to give the damaged ligaments a chance to heal. Some horses are eventually able to return to full work.
The bones within the fetlock can be susceptible to damage close to the joint known in veterinary terms as subchondral bone damage as well as fragmental or major fractures
Repetitive subchondral damage can result in changes to the mechanics of the bone making it more vulnerable to fracture but any of the bones within the fetlock can also fracture due to acute single overload.
Fractures are most common in racehorses and highlevel event horses in fast exercise. As with human bone breaks a fetlock fracture may be repairable with surgery
Joint damage
Ligament or bone damage can cause changes to occur within the fetlock joint itself. Inflammation and an increase in synovial fluid may cause lameness which your vet may treat with reduced exercise and antiinflammatories.