Forearm Fractures: Radial and/or Ulnar Shaft Fractures

Overview
Nearly all displaced diaphyseal fractures of the forearm require surgical management. Most nondisplaced fractures of both the radius and ulna also warrant surgical management because of the inherent difficulty of immobilizing these both-bone forearm fractures. Plate fixation reliably improves the functional outcome of most of these injuries and is considered the gold standard for treatment. Usually the only forearm fractures treated conservatively are pediatric and nondisplaced isolated radial/ulnar shaft fractures.

The severity of the soft-tissue injuries surrounding forearm fractures determines the extent of the surgical intervention required. Severe pain, weakness, or paresthesias may be indicators of neurovascular injuries. A vascular examination involving the axillary, brachial, radial, and ulnar pulses is necessary. In addition, a thorough neurologic examination should be performed that includes a motor and/or sensory assessment of the radial, posterior interosseous, anterior interosseous, medial, and ulnar nerves.

Preoperative radiographs should be obtained and should include standard AP and lateral views of the forearm. In addition, views of the elbow and/or wrist are usually necessary for full evaluation of the extent of the injury to the forearm.

Open fractures typically require irrigation and débridement of the injury site in addition to internal plate fixation of the fracture. Widely contaminated or devitalized wounds may require initial external fixation of the fracture prior to definitive treatment with plate fixation. An impending compartment syndrome in the forearm requires immediate fasciotomy with stabilization.

For most forearm fractures, 3.5-mm small-fragment compression plates are recommended. Stable fixation usually requires at least three bicortical screws on each side of the fracture. Locking plates are usually not necessary for stable fixation of simple diaphyseal fractures.

Surgical Management
Once the arm is fully exsanguinated, the incisions are marked out for both radial and/or ulnar fixations. For most fractures of the radius, the extensile volar approach to the forearm described by Henry is recommended. For direct posterior exposure to the ulna, an incision along the subcutaneous border of the ulna is recommended. The radius is usually fixed first because the exposure is typically more complicated. When one bone is more comminuted than the other, however, the simpler fracture is fixed first to allow better reduction of the fracture.

In the Henry approach, used for access to the proximal and middle third of the radius, the fascial interval just radial to the biceps tendon and just ulnar to the brachioradialis muscle is incised. The superficial interval in the proximal forearm is between the brachioradialis and pronator teres muscle, whereas the interval in the distal forearm is between the brachioradialis and flexor carpi radialis. The radial artery travels just underneath the brachioradialis muscle and must be protected during this approach. To have direct exposure to the proximal radius, the supinator must be incised to allow for deep surgical dissection. This incision has the risk of injuring the posterior interosseous nerve as it travels underneath the supinator muscle. Supinating the forearm and incising the supinator on the ulnar border of the radius minimizes the risk of injuring the posterior interosseous nerve. To expose completely the middle third of the radius, the pronator teres and the flexor digitorum superficialis muscles can be detached from the radial aspect of the radius.

Once the radial fracture is exposed, the fracture is reduced under direct visualization. Principles of compression-plate fixation are used for simple fractures. A bridge plating technique may be used for extensively comminuted radial fractures. The plate must be precontoured to recreate the dorsal bow of the middle and proximal third of the radius.

Once the radius is stabilized, the elbow is flexed and the ulna is exposed between the flexor carpi ulnaris and extensor carpi ulnaris muscles. A 3.5-mm small-fragment compression plate is then placed under the extensor carpi ulnaris muscle, stabilizing the ulna.

Forearm alignment and rotation are checked under fluoroscopy or via intraoperative full-length radiographs. Fascial closure in the volar forearm is usually not advised because of the potential risk of compartment syndrome with reperfusion. The tourniquet is usually released prior to closure to assess for excessive arterial bleeders. Finally, the arm is placed in a posterior long arm splint.

Postoperative Management
Immediately after surgery, finger flexion and extension is encouraged. The long arm splint is removed approximately 5 to 7 days after surgery, and shoulder, elbow, forearm, and wrist motion is encouraged. Active-assisted pronation and supination of the forearm is emphasized as part of the rehabilitation protocol. Heavy lifting, full weight bearing, and sports are restricted for the first 6 to 8 weeks after surgery.

Complications
Early complications include nerve palsy, compartment syndrome, and wound infection. Nerve palsy usually involves is a result of injury to [Author: Edit okay?] the superficial radial nerve during the retraction process. Late complications include nonunions, refracture after plate removal, and synostosis. Resections for synostosis in the proximal and distal forearm tend to have poorer outcomes.

Special Considerations
Fractures in the proximal third of the ulna with an associated radial head dislocation are known as Monteggia fractures [Author: I’ve usually seen “Monteggia fracture-dislocation”]. Surgical stabilization of the proximal ulnar fracture is necessary for stable relocation of the radial head. Isolated fractures in the distal third of the radius with associated dislocation of the distal radioulnar joint are called Galeazzi fractures. Analogous to the treatment of Monteggia fractures [Author: or fracture-dislocations], Galeazzi fractures require surgical stabilization of the radial fracture to reduce the distal radioulnar joint.

Clinical Topics

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