Equine standing fracture repair shows early promise
MedWire News: Horses with a lower limb fracture can feasibly be managed with repair under standing sedation, a preliminary analysis indicates.
Although the technique is in its infancy, it offers potential advantages over fracture repair under general anesthesia and warrants continued evaluation, say Polly Compston and Richard Payne, both from Rossdales Equine Hospital, Newmarket, UK.
Writing in the Equine Veterinary Journal, Compston and Payne report short- and long-term outcomes on a series of 34 racehorses that had lower limb fractures repaired under standing sedation.
Fracture sites were the proximal phalanx (incomplete sagittal fracture, n=14), the third metacarpal bone (lateral condyle, n=12, and medial condyle, n=7), and the third metatarsal bone (lateral condyle, n=1).
All animals had their fractures repaired under standing sedation and local anesthesia. Specifically, they received acepromazine premedication followed by intravenous boluses of detomidine and butorphanol. Either 4- or 6-point nerve block was performed and additional mepivacaine was given during surgery as needed.
Compston and Payne explain that, during surgery, horses were positioned so that the foot of the fractured limb was perpendicular to the floor. In the cases described here, the primary surgeon had two assistants: one to pass instruments and one to hold the drill hole. Most repairs required either two or three screws, and the technique was modified over time to exclude the routine use of a tourniquet.
"It is important that the floor is nonslip," the researchers add. "Any movement once the support bandage has been removed may cause destabilization of a nondisplaced fracture, and therefore efficient surgical technique and a fully competent surgical team is required to minimize surgical time and therefore the period during which the horse has to remain still."
In terms of outcomes, 30 horses had no perioperative problems. One horse had a cecal impaction that was refractory to treatment and ruptured, necessitating euthanasia; other complications included colon impaction, postoperative colitis associated with Clostridium difficile infection, and mild bandage-associated skin sores, all of which resolved uneventfully.
The median duration of hospitalization was 3 days and 33 horses survived to discharge. Of the 30 horses with at least 3 months of follow-up, all became sound at trot and 29 have returned to training; of these, three had unresolved lameness of the fractured limb and were retired, while four horses were retired due to lack of ability.
Long-term follow-up revealed that 20 horses returned to racing a mean of 7.43 months after the fracture repair, and 12 had either been placed or won at least one race. Importantly, all owners/trainers agreed that they would have fractures in other horses repaired in this way in the future.
"Horses in this cohort returned to racing an average of 81 days earlier than horses that had a fracture repaired under general anesthesia," Compston and Payne remark.
They conclude: "This study shows no disadvantages to repairing these nondisplaced fractures of the lower limb under standing sedation and local anesthesia compared with under general anesthesia. Facilities and experience are important when considering this technique."
By Joanna Lyford