Rockwood Children CH8

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CHAPTER 8 • Fractures of the Distal Radius and Ulna

Open reduction for closed unstable or irreducible fractures is typically performed through a volar approach to the distal radius. A longitudinal incision overlying the flexor carpi radi- alis (FCR) tendon is created, centered on the fracture site with awareness of the location of the distal radial physis. Classically, superficial dissection is carried out in the interval between the radial artery and the FCR. In distal radius fractures, dissection may also be performed directly through the FCR sheath by incising the roof of the FCR sheath and retracting the tendon ulnarly; the intact radial FCR sheath, when retracted, will serve to protect the adjacent radial artery. Deep to the FCR, a fat plane will be encountered overlying the pronator quadratus. The pro- nator quadratus is incised along its radial border, leaving a small cuff of tissue for subsequent repair, and elevated in a subperi- osteal fashion from radial to ulnar. Although this muscle can be interposed in the fracture site, the volar periosteum is more commonly interposed. This is evident only after elevation of the pronator quadratus. The periosteum is extracted from the physis with care to minimize further injury to the physis. Upon completion of pronator quadratus elevation, the fracture may be easily visualized. ❑❑ Expose distal radius • Volar approach most common ❑❑ Superficial dissection through FCR sheath or in FCR–radial artery interval ❑❑ Incise radial margin of pronator quadratus with radial-to-ulnar subperiosteal elevation ❑❑ Fracture exposure and reduction • Careful extraction of interposed periosteum or soft tissue ❑❑ Stable fixation with either wires or plate-and-screw constructs ❑❑ Leave fascia open After adequate fracture exposure is obtained, bony reduction is performed easily using similar maneuvers as during closed manipulations. Once anatomic fracture alignment is achieved, percutaneous smooth K-wires may be used for stabilization of the reduction. The method of pin insertion is the same as after closed reduction; use of a small incision during wire insertion will minimize risk to the radial sensory nerve and extensor tendons. Similarly for open fracture care, fracture reduction and fixation is performed, usually with two smooth wires, after thorough irrigation and debridement. In the uncommon open physeal fractures, care is taken with mechanical debridement to avoid injury to the physeal cartilage. If the soft tissue injury is severe, supplemental external fixation allows observation and treatment of the wound without jeopardizing the fracture reduction. The original open wound should not be closed pri- marily. Appropriate prophylactic antibiotics should be used depending on the severity of the open fracture. ❑❑ Meticulous layered wound closure ❑❑ Postoperative cast immobilization Technique ✔ ✔ Open Reduction and Fixation of Distal Radius Fractures: KEY SURGICAL STEPS

Plate fixation may also be used for stabilization following open reduction. While the indications for plate fixation evolve and remain patient- and surgeon-dependent, plate fixation is more strongly considered in multitrauma patients, comminuted fractures, older patients nearing or at skeletal maturity, refrac- tures, and fractures at the metaphyseal–diaphyseal junction in whom percutaneous pinning techniques are more challenging. Following standard surgical exposure and fracture reduction, neutralization or dynamic compression plates are applied to the radius using techniques similar to adult fracture care, with a few caveats. Standard 3.5-mm implants may be too bulky for younger or smaller pediatric patients. In these situations, double-stacked one-third tubular plates, 2.7-mm plates, or 2.4-mm plates may be used. In addition, given the rapid bony healing, stout peri- osteum, and postoperative cast immobilization characteristic of pediatric fracture care, two cortices of fixation may be sufficient distal to the fracture site. Finally, in patients with skeletal growth remaining, implants should be placed sparing the distal physis. In older adolescents at skeletal maturity or those with intra-ar- ticular injuries, volar locking plates may be used for internal fixation. Although a host of commercially available plates are available, the principles are constant: meticulous exposure, anatomic fracture reduction, and stable fixation proximal and distal to the fracture site. Care should be made in anatomically contoured volar locking plates to avoid penetration of obliquely angled distal locking screws into the radiocarpal joint, as well as excessive dorsal prominence of screws, which may lead to late extensor tendon irritation or rupture (Fig. 8-41). Following fixation, the pronator quadratus, FCR sheath, and subcutaneous tissues are closed in layers, followed by skin clo- sure. In cases of plate fixation, short-arm cast immobilization is sufficient postoperatively.

Fixation of Intra-Articular Fractures Preoperative Planning ✔ ✔ Open Reduction and Fixation of Intra-Articular Fractures:

PREOPERATIVE PLANNING CHECKLIST

❑❑ Standard, radiolucent hand table

OR table

❑❑ Supine

Position/positioning aids

❑❑ Variable depending on surgeon preference ❑❑ K-wires, small fragment plating systems, anatomically precontoured volar locking plates, small joint arthroscope ❑❑ Nonsterile tourniquet placed on proximal brachium ❑❑ Adequate preoperative imaging, including CT or MRI

Fluoroscopy location

Equipment

Tourniquet

Other

The rare Salter–Harris type III or IV fracture or “triplane” frac- ture 157 may require open reduction if the joint or physis can- not be anatomically reduced via closed means. If anatomic