Fractures of the Proximal Sesamoid Bones in Horses

Last Updated on March 29, 2022 by Allison Price

Fractures of the Proximal Sesamoid Bones

The location of fractures in the proximal sesamoid bone is what determines their classification. Apical sesamoid fractures are the most common in Standardbreds, Thoroughbreds, and Thoroughbreds. These fractures are often caused by excessive overextension, and are often associated with suspensory injury to the ligament. Standardbreds’ hindlimb may fracture at the lateral proximal sesamoid. This is due to torque forces caused by wearing a trailer-type footwear. Mid-body, basilar and abaxial fractures can also occur. They may affect one or both sesamoids. Except for some base and abaxial fractures, most are articular. Acute lameness is often accompanied by heat, pain and heat. This can be exacerbated when the fetlock is bent. There is often hemarthrosis and synovial effusion of the metacarpal/tarsophalangeal joint. Radiographical confirmation of diagnosis is made. Thoroughbred racehorses older than 2 years ran at the same level or better when horses had apical sesamoid fragments removed arthroscopically. After fragment removal, horses with apical fractures in the forelimb medial-proximal sesamoid will be less likely to race. After surgery, the prognosis is also affected by the presence of suspensory dermitis (see Subspensory Desmitis for Horses). A horse with apical semmoid fractures in their forelimbs is less likely to race than one with a fracture in their hindlimbs (56%) Racing performance is not affected by the size and shape of apical sesamoid fractures. To return to racing, mid-body fractures usually require reduction with lag screw(s). Fixation. The prognosis for these types of fractures is 75% (44% in another research). Basilar fractures that involve a small portion of the sesamoid are less likely than those that involve the entire base of horses or horses with associated articular diseases (poor prognosis). A complete disruption of the suspensory system, including the fractures of both sesamoid bone, can cause a severe injury. However, there are some horses that can be saved for breeding through surgical arthrodesis.

Allison Price
Allison Price

I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!