Postoperative management of external fixators in dogs and cats

Despite the widespread use of external skeletal fixation in small-animal practice, little information is available regarding postoperative care. Here are some tips to promote optimal healing, keep patients comfortable, and avoid complications.


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External skeletal fixation is frequently used for fracture stabilization, arthrodesis, and angular limb deformity correction in dogs and cats.1-8 While construct design and application can vary substantially, all external fixators (linear, circular, and hybrid) consist of an extracorporeal frame and fixation elements—either pins or small-diameter wires—that stabilize the engaged bone segments.1 The protruding fixation elements and external frame present unique considerations with regard to appropriate postoperative management.

A variety of recommendations have been made regarding the management of external fixators; however, clinical studies evaluating the efficacy of postoperative management methods have not been reported. Our recommendations in this article reflect the limited research available in human patients and animal models, as well as our clinical experiences.

FIXATOR PREPARATION


1. The limb and fixator are cleaned using an unfolded and rolled gauze sponge in preparation for bandaging after surgery. The gauze has been moistened with chlorhexidine solution.
Decreasing postoperative morbidity associated with external skeletal fixation begins during and immediately after surgery. Proper application is essential to preventing complications and includes using safe corridors that avoid placing fixation elements through large muscle groups or neurovascular structures, predrilling pilot holes for pin placement, using threaded fixation pins, and ensuring that the construct applied provides adequate stability.1


2. The end of the fixation pin has been cut close to the clamp's primary fixation bolt. A protective plastic cap has been placed and glued on the end of the trimmed fixation pin.
Make release incisions through the skin and continue them via blunt dissection through the underlying soft tissues when placing fixation elements. The release incisions should be a minimum of 1 cm and of sufficient length that the fixation element does not create tension in the adjacent tissues as the limb is put through a full range of motion.2 Thoroughly tighten all clamps, bolts, and nuts associated with the frame.


3. The ends of the wires in this circular fixator are curled around the ring to prevent damage from sharp ends.
After surgery, clean the fixator and limb of any blood or debris, and dry the fixator and limb segment (Figure 1). Cut fixation pins flush with the clamps, and apply protective plastic caps to the cut ends of each pin (Figure 2). With circular or hybrid fixators, cut the ends of the wires about 2 to 3 cm from the fixation bolt, and curl the wire ends around the frame (Figure 3).