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CHAPTER 8 • Fractures of the Distal Radius and Ulna

Technique

disturbance. Wires passed obliquely from distal to proximal are effective for radial styloid and dorsal lunate facet fracture frag- ments; similarly, transverse epiphyseal pins may impart stability to articular fracture fragments. In older patients nearing or at skeletal maturity, adult-like locking plate constructs may be used. Reduction and Fixation of Distal Ulna Fractures Open reduction is performed in cases where acceptable align- ment is not achieved following radial reduction and attempted closed manipulation. This is an indication for open reduction. Preoperative Planning Preoperative planning and patient positioning are similar to that of displaced distal radius fractures. Surgical Approach Incisions for surgical exposure of the ulna are typically ulnar or dorsoulnar, though ideally, surgical exposure approaches the ulna from the side of periosteal disruption. In physeal fractures, the periosteum is typically torn opposite the Thurston–Holland fragment; in metaphyseal injuries, periosteal injury is opposite the direction of displacement. Deep dissection is most commonly made in the extensor carpi ulnaris—flexor carpi ulnaris interval ulnarly or the extensor digiti quinti—extensor carpi ulnaris inter- vals dorsally. Careful subperiosteal elevation may be performed in the zone of injury, which is typically already traumatized from the fracture. Interposed soft tissue (periosteum, extensor tendons, abductor digiti quinti, or flexor tendons) may then be identified and must be extracted from the fracture site. 1,81,184

✔ ✔ Fixation of Displaced Distal Ulna Fractures: KEY SURGICAL STEPS

❑❑ Expose distal ulna • Preserve distal ulnar physis, capsular attachments of DRUJ and ulnocarpal joint, and ulnar wrist ligaments whenever possible ❑❑ Anatomic reduction of ulnar fracture ❑❑ Stable fixation based on fracture pattern and patient age • K-wire fixation • K-wire with tension-band construct • Plate-and-screw fixation ❑❑ Assess DRUJ alignment and stability intraoperatively ❑❑ Postoperative cast immobilization Following exposure, soft tissue extraction, and bony reduction, if fracture instability persists, internal fixation is performed. Often, a single small-diameter smooth K-wire can be used to maintain alignment. This K-wire may be passed obliquely from distal to proximal, crossing the fracture site. In older patients with larger bones and greater instability, two parallel K-wires may be used, and this may be further supplemented by tension-band fixation (Fig. 8-45). A small drill hole made proximal to the fracture site is created, and a nonabsorbable braided suture or small-caliber stainless steel wire is passed through the drill hole and around the previously placed K-wires in a figure-of-eight fashion. Pins are typically removed after 4 weeks following radiographic con- firmation of bony healing. Plate-and-screw fixation may also be performed in distal metaphyseal fractures and/or older, skeletally mature patients. Use of smaller implants, distal locking screws, or mini-fragment blade plates will assist in obtaining adequate

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Figure 8-45.  A: Plain radiographs depicting displaced distal radial metaphyseal and ulnar styloid fractures. Given the fracture and distal radioulnar joint instability, the injury was treated with closed reduction and percutaneous pinning of the distal radius as well as open reduction and tension-band fixation of the ulnar styloid. B: Follow-up radiograph following reduction and fixation demonstrates anatomic alignment. The prior radial pins have been removed, and the parallel smooth wires used for tension-band fixation of the ulnar styloid are seen. (Courtesy of Children’s Orthopaedic Surgery Foundation.)