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Equine Health Resource

Breakdown Injury, Traumatic Disruption of Suspensory Apparatus

Synonyms: Catastrophic Breakdown

The suspensory apparatus supports the fetlock. In racehorses and sometimes in foals, the entire structure of the suspensory apparatus can rupture, causing collapse of the fetlock to the ground.

Breakdown can occur due to complete fracture of the sesamoids, rupture of the suspensory ligament, or rupture of the distal ligaments of the proximal sesamoids, or a combination of injuries.

This catastrophic injury occurs in racehorses when the tension in the suspensory apparatus is overloaded, usually due to over-fatigue of the system.

A similar syndrome is seen in foals that have been confined for long periods of time and then overexert.

Prognosis & Relevant Factors

The prognosis for this injury is generally grave. In many cases, the blood supply to the lower limb is lost. In cases in which the blood supply still exists, the only course is usually fetlock fusion (arthrodesis), leading to an animal that may be breeding sound.

Author: Doug Thal DVM Dipl. ABVP


Higgins AJ, Snyder JR eds. The Equine Manual. 2nd Ed. Edinburgh: Elsevier Saunders 2006.


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