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

The study evaluates a bone graft collecting technique from the upper section of the horse’s front leg or humerus. It reveals that the technique provides a limited quantity of porous bone or cancellous bone, but also comes with potential dangers, evidenced by one horse fracturing its leg during the post-procedure recovery.

Procedure Details

• The research involved an experimental study on eight horses, aged between 3 and 15 years, and weighing between 495 to 605 kg.
• The horses were put under anesthesia and placed on their sides.
• A 7 to 10 cm incision was made on the lateral side of the upper section of the foreleg, from which a 12 mm defect was incrementally created.
• An Acumed system, a human bone graft harvesting tool, was drilled through this defect to collect a “core” of porous, cancellous bone.
• In five horses, additional cancellous bone was collected with conventional tools and weighed. The bone samples were also subjected to a histological examination.
• The horses were monitored and assessed for how well they recovered from the anesthesia, complications regarding the incision, and postoperative lameness (difficulty in walking).

Results

• The average total duration for harvesting bone, using either the Acumed system or traditional techniques, was 38 minutes, with a range between 32 to 47 minutes.
• The average cancellous bone weight collected with the Acumed system was minimal at 3.6 g, while that collected conventionally was significantly higher, at 25.6 g. This demonstrated that the Acumed system yielded limited cancellous bone.
• Minimal complications with the incisions or postoperative lameness were recorded. However, one horse (representing 12.5% of the sample) fractured its operated humerus during recovery from anesthesia, indicating potential risks associated with the procedure.

Conclusions

• Although the Acumed system provided limited cancellous bone using the described technique, the collected quantity was comparable with traditional harvesting tools.
• Although the procedure was associated with minimal postoperative complications, the risk of catastrophic fracture, as seen in one of the horses, necessitates further research to assess the impact of this procedure on humeral fracture strength.
• Due to the aforementioned risk of catastrophic fracture, the technique cannot be recommended for use in clinical cases, particularly when an unassisted recovery from generalized anesthesia is planned.