Percutaneous Pinning for Fracture Repair in Dogs and Cats

Key points

Case selection

Traditional principles of case selection for intramedullary or cross-pinning stabilization of fractures apply when considering patients as candidates for percutaneous pinning. Salter-Harris type I and II physeal fractures are the most amenable to percutaneous pinning stabilization, for several reasons. Pins mainly serve to counteract bending forces, whereas rotational and compressive forces are poorly neutralized, even when multiple pins are used. Therefore, juxta-articular, noncomminuted

Preoperative management and planning

Preoperative planning for percutaneous pinning fracture stabilization must begin with appropriate case selection, as already described. A thorough physical and orthopedic examination should be performed to identify any significant concomitant injury. At a minimum, thoracic radiographs and orthogonal projection radiographs of the affected bone are acquired. Radiographs typically require moderate sedation or anesthesia to achieve optimal positioning and projections. It is strongly recommended

Preparation and patient positioning

At the time of surgery, the entire affected limb must be aseptically prepared to enable adequate intraoperative maneuvering required for closed reduction and percutaneous insertion of pins. A full limb preparation is also required to allow conversion to a traditional open approach if needed. The hanging limb preparation is useful to fatigue contracted muscles and facilitate closed reduction. Femoral capital physeal fractures are approached with the patient in lateral recumbency, affected limb

Fracture reduction and surgical approach

For closed reduction of physeal fractures, the precise technique depends on the bone, the involved physis, and the direction and degree of displacement of the epiphysis. The first principle in reduction is to minimize harm to the physis. To achieve this, the maneuver should generally be 90% traction and 10% leverage.¹⁴ Initial traction may slightly increase the displacement and angular malalignment at the fracture site. The epiphysis is then translated into alignment while maintaining traction.

Surgical procedure

General principles of traditional open physeal fracture repair with pins must be adhered to with percutaneous pinning. To decrease the risk of premature physeal closure, pins must be placed as perpendicular to the physeal plate as possible. Angulation of pins greater than 45° to the physis predisposes to epiphysiodesis.¹⁶ Threaded pins are not routinely used by the authors for percutaneous pinning because of the inherent weakness at the thread-shaft interface, risk of hindering longitudinal

Immediate postoperative care

Fracture reduction and pin placement are carefully assessed on postoperative radiographs. For all cases, parenteral analgesia is administered for up to 12 hours to address immediate postoperative pain. Because of the limited soft tissue trauma induced by surgery, analgesic requirements are expected to be substantially lower than if the procedure was performed with a traditional open approach. There are very few risk factors for infection (clean procedures, young patients, minimal surgical

Rehabilitation and recovery

Early return to weight bearing and good limb function is anticipated following percutaneous pinning. Because the minimum size and number of pins that will provide adequate stability are typically used, cage rest should be strictly enforced until complete union of the fracture is documented. If strict crate rest is not enforced, these repairs are at high risk for implant failure and pin migration. With preservation of surrounding soft tissue structures and the tremendous capacity for healing

Clinical results

Percutaneous pinning for tibial and femoral fractures was first described in 1989, although it was performed in a “blind” manner without intraoperative fluoroscopy.¹⁷ Osseous union was achieved in 55 of 56 fractures treated in this manner. Age, body weight, fracture type, and time from injury to repair were found to influence overall outcome in these cases. A small retrospective case series on percutaneous pinning under fluoroscopic guidance was described in abstract format.⁷ In this report, 3

Summary

Percutaneous pinning is a feasible and safe method for stabilizing selected Salter-Harris type I and II physeal fractures in dogs and cats. Surgical intervention must be performed soon after the time of trauma, otherwise closed reduction cannot be achieved. The procedure is technically demanding; surgeon experience, intraoperative fluoroscopy, appropriate surgical instrumentation, and strict case selection are all required for consistent successful outcomes. Although clinical comparisons