The suspensory ligament (SL) ties into the top of the cannon bone, just below and behind the carpus in the front limb and the hock in the hind limb. This structure runs down the back of the cannon bone, between the two splint bones. Two thirds of the way down the cannon, it splits into inside (medial) and outside (lateral) branches that attach to the sesamoid bones at the fetlock. Fibers pass on as the extensor branches to blend into the extensor tendons.
The SL is a critical structure for the sling function of the fetlock joint and is unfortunately a common site for the development of lameness conditions.
Proximal suspensory injury is injury to the highest part of the suspensory ligament, its attachment to the bone. This is a common soft tissue injury in sport and race horses and comes from repetitive loading or overload of this structure.
Hind limb proximal suspensory disease is more difficult to diagnose than the condition in the front limb. It requires a very thorough lameness evaluation in most cases. In the hind limb, there is usually very little noticeable swelling. Pain is often not obvious when pressing on this area. Therefore the cornerstone of diagnosis is blocking, and imaging the area with ultrasound.
The condition is more difficult to treat than the condition in the forelimbs, tending to recur after return to work. It may overlap with the diagnosis of DSLD, a generalized deterioration of the suspensory ligament.
Hind limb suspensory injury treatment requires extended rest and gradually increasing exercise, with repeated reevaluation by a vet, and ultrasound to assess healing progress. Regenerative therapies may have value in some cases, as does shock wave, and several surgical approaches.
Other Diagnoses Considered
Treatments May Include
Prognosis & Relevant Factors
Horses with fetlocks that hyperextend (dropped fetlock) have a poor prognosis for return to performance.
Horses with post-legged conformation (very straight through the hock and stifle) more commonly have this condition. Horses with very post-legged conformation and sagging fetlock have a worse prognosis.
In most cases, treatment of these horses will not restore them to performance level.
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