Transfixation Pin Cast Recovery: Timelines Set

Researchers at Colorado State University (CSU) set time guidelines for the use of transfixation pin casts for horses with comminuted phalangeal fractures. They found that horses with fractures maintained in this type of cast for 40-80 days had increased survival rates without an increased risk of complications from the procedure.

One of the greatest challenges clinicians face when treating horses with comminuted limb fractures is the need to get the horse bearing weight as soon as possible. If veterinarians aren't able to do this, they run the risk of the horse developing contralateral (opposite limb) laminitis. Researchers said the pin cast allows the horse to immediately place weight on the affected limb.

JoLynn Joyce, DVM, a researcher involved in the study, explained that comminuted limb fractures are not uncommon in adult horses, but the exact causes are still unknown.

"It is speculated that repetitive loading of the bone over time results in microfractures, which can then lead to a catastrophic fracture when the bone is loaded in different forces," Joyce said. "Often times, the bone is fractured such that internal fixation with plates and screws can be performed. However, when the bone is severely comminuted (reduced to multiple fragments), then transfixation pin casting can be used."

Joyce explained that this technology consists of placing large bore pins through the cannon bone above the fracture site and incorporating the pins in a fiberglass cast. "By doing so, the horse can bear weight immediately, and the weight is transferred from the ground, up the cast, and through the pins," she explained. "By doing this, the weight is not placed at the fracture site; rather the fracture is 'suspended,' allowing it to heal."

Researchers examined the records of 20 horses treated at CSU, eight of which had forelimb fractures and 12 that had hind limb fractures. They found that horses maintained in the transfixation pin casts for at least 40 days had better survival rates than those in the cast for less time.

Joyce said there were complications in some of the cases. "The greatest complication that we observed with this procedure was secondary fracture of the cannon bone associated with the transfixation pins," she said. Other complications included pin breakage and pin tract infections.

Researchers who completed the study published in the Sept. 1 issue of the Journal of the American Veterinary Medical Association were Joyce; Gary Baxter, VMD, MS, Dipl. ACVS; Tiffany Sarrafian, DVM; Ted Stashak, DVM, MS, Dipl. ACVS; Gayle Trotter, DVM, MS, Dipl. ACVS; and David Frisbie, DVM, PhD, Dipl. ACVS.

About the Author

Chad Mendell

Chad Mendell is the former Managing Editor for .

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