Basic Orthopedics for the Small Mammal Patient

Orthopedic trauma in rabbits, rodents, and ferrets occurs from household accidents, injury from a falling object, a closing door, attacks from another animal, an owner stepping on an animal, or by poor cage design. After initial evaluation of other body systems, an orthopedic and neurologic examination is performed. Orthopedic trauma is rarely an emergency unless a spinal fracture is suspected. Examples of urgent orthopedic trauma include open fractures and articular fractures. Regardless of the type of orthopedic injury, all small mammal trauma patients should be evaluated on an emergency basis to evaluate other body systems and administer appropriate supportive therapy and analgesics. Once the patient is metabolically and cardiovascularly stable all wounds and open fractures are addressed. Under sedation, wounds are clipped and cleaned and fractures or joint instability of the distal limbs (below the elbow and stifle) are bandaged and splinted until definitive surgery can be performed. For fractures proximal to the elbow and stifle only a spica splint is applied to the leg. It is important to note that rabbits with open fractures tend to do worse than other veterinary species because of the early development of osteomyelitis, which is difficult to treat in this species. Preoperative planning can be difficult in small mammals because they are not easy to keep exercise restricted. They also tend to chew at bandages, splints, and wounds. Most important is keeping the patient comfortable with analgesics and preventing possible secondary complications of anesthesia and surgery in these species. An issue related to rabbit orthopedic repair is their relatively hard and brittle long bones compared to those of dogs and cats. The bones of rabbits comprise only 8% of the total bodyweight, compared with 13% in cats. Although rabbit bone does heal well when appropriate orthopedic principles are applied, the application of large implants overprotect the bone, leading to rapid bone resorption (mimicking disuse osteopenia and osteoporosis) and secondary failure of the repair. Over protection of a long bone with too strong of a repair will lead to this complication in any species, this is not specific to rabbits. Successful fracture repair in rabbits is possible when appropriately sized implants are chosen. Open fractures are cultured and antibiotics is started. Routine post-operative analgesia and supportive care are instituted as described for other surgical procedures.