Intramedullary Single-Kirschner-Wire Fixation in Displaced Fractures of the Fifth Metacarpal Neck (Boxer's Fracture).

Abstract

For this procedure, the injured arm of the patient is placed on an arm table. The incision is made 1 to 2 cm longitudinally over the ulnar base of the fifth metacarpal bone. The cortical bone is opened with an awl, and a bent 1.6-mm Kirschner wire is inserted into the medullary canal. After reaching the fracture region, the fracture is anatomically reduced. The Kirschner wire is then advanced into the head of the fifth metacarpal, securing the reduction. Malrotation can be addressed in this stage by rotating the wire under fluoroscopic control. After ensuring anatomical reduction clinically and by fluoroscopy, the wire is shortened under the skin, followed by closure of the incision. We utilize a mid-hand brace for splinting. Nonoperative treatment is common for fifth metacarpal neck fractures in the absence of malrotation, excessive angulation, and shortening. Other surgical techniques include a similar procedure that involves the use of multiple Kirschner wires, plate fixation, transverse Kirschner wire pinning, and, less commonly, retrograde headless screw fixation2,7-9. The main advantage of this technique is the preservation of the metacarpophalangeal joint and the minimal soft-tissue damage. Additionally, the use of a single Kirschner wire provides stability at low cost. With some experience, this surgery can be performed within 20 minutes1,9. This procedure provides good fracture reduction and stabilization8. The outcome is usually satisfactory, with very low Disabilities of the Arm, Shoulder, and Hand scores1. Malrotation, angulation, and shortening are sufficiently addressed, and the technique shows the same results as fixation performed with use of 2 intramedullary wires. Bending the Kirschner wire to ensure easy gliding in the medullary canal provides the opportunity to reduce the metacarpal neck once the wire is safely in the head.Aim distally as you open the cortical bone with the awl in order to facilitate the insertion of the Kirschner wire.The primary reduction should be made manually, not by the wire. Subacute fractures and substantially displaced fractures require direct force for a satisfactory reduction, which cannot be achieved by rotation of the wire only.The cortical bone on the metacarpal head is very thin. Take care not to drive the Kirschner wire through the cortical bone and into the joint.Shorten the wire under the skin approximately 1 cm above the bone surface; this ensures easy removal and prevents skin irritation. K-wire = Kirschner wire.