Evaluation of a technique for collection of cancellous bone graft from the proximal humerus in horses.
OBJECTIVE
To describe a technique for collecting cancellous bone graft from the proximal humerus in horses.


METHODS
Prospective evaluation of an experimental bone graft collection technique.


METHODS
Eight horses, 3-15 years, weighing 495-605 kg.


METHODS
Horses were anesthetized and positioned in lateral recumbency. The lateral aspect of the proximal humerus was exposed by a 7-10-cm incision extending distally from the greater humeral tubercle, followed by sharp dissection through the omotransversarius muscle and between the infraspinatus and deltoideus muscles. A 12-mm cortical defect was incrementally created in the lateral proximal humerus. Human bone graft harvesting equipment (Acumed, Beaverton, OR) was drilled through this defect to collect a core of cancellous bone. In five horses additional cancellous bone was then collected with conventional instruments. Bone samples were weighed and histologically examined. Horses were monitored and graded for quality of anesthetic recovery, incisional complications, and postoperative lameness.


RESULTS
Total mean (+/-SD) surgical time for harvesting bone with the Acumed system and traditional techniques (n=5) was 38+/-6 minutes (range, 32-47 minutes). Mean cancellous bone weight collected with the Acumed system was 3.6+/-0.8 g (range, 2.0-4.6 g), and cancellous bone collected conventionally was 25.6+/-7.5 g (range, 16.8-34.2 g). Minimal incisional complications or postoperative lameness were observed. Mortality was 12.5%; one horse fractured the operated humerus during anesthetic recovery.


CONCLUSIONS
The Acumed system provided limited cancellous bone when used with the technique described. However, the quantity of cancellous bone collected with traditional harvesting instruments was comparable to other sites used in horses. The procedure was associated with minimal postoperative incisional complications or lameness, but because one horse suffered a catastrophic humeral fracture further research is required to assess the effects of this procedure on humeral breaking strength.


CONCLUSIONS
Based on the risk of catastrophic fracture, this technique cannot be recommended for use in clinical cases, especially if an unassisted recovery from general anesthesia is planned.
Harriss
Fiona K
FK
Veterinary Medical Teaching Hospital, Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
Galuppo
Larry D
LD
Decock
Hilde E V
HE
McDuffee
Laurie A
LA
Macdonald
Melinda H
MH
D000818:Animals; D016025:Bone Transplantation / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D005260:Female; D018460:Fractures, Comminuted / Q000209:etiology / Q000662:veterinary; D006736:Horses; D006810:Humeral Fractures / Q000209:etiology / Q000662:veterinary; D006811:Humerus / Q000601:surgery* / Q000637:transplantation*; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D016896:Treatment Outcome