A 54-year-old, right-hand-dominant, industrial worker is brought to your hospital after his left arm was caught in a machine at work. He sustained fractures to both the radius and ulna, which were imaged in the emergency department and are shown in Figure 6–21A and B. This is a closed injury and the extremity remains neurovascularly intact with moderate swelling present. The plan is for operative fixation of these fractures, and the patient is prepped for transport to the operating room.

Figure 6–21 A–B

Which of the following are indications for surgical management of forearm fractures in an adult?

1. Fracture of the radius with 75% translation and slight apex ulnar angulation

2. Displaced fractures of both the radius and ulna

3. Fracture of the ulna with an associated radial head dislocation

4. Fracture of the radius with an associated DRUJ disruption

5. All of the above

Discussion

The correct answer is (E). In adults, the restoration of anatomic alignment of the radius and ulna is critical to forearm function, to include the proximal radioulnar joint, distal radioulnar joint (DRUJ), and the radial bow. Treatment of adults with displaced forearm fractures or complex injuries such as those listed in the answer choices is associated with unsatisfactory outcomes as often as 92% of the time. These poor outcomes are due to a variety of reasons including malunion, nonunion, or radioulnar synostosis. Forearm fractures in adults are almost exclusively treated surgically with the exception of minimally or nondisplaced fractures of the ulnar shaft, which in isolation can be managed with casting or fracture bracing with satisfactory outcomes.

Once the patient is prepped and draped in the operating room, you draw out your planned incisions on the forearm.

What is the primary reason for using two incisions as opposed to one incision when performing ORIF of both bones of the forearm?

1. Higher rates of fracture union

2. Lower risk of infection

3. Improved accuracy with restoration of the native radial bow

4. Lower risk of synostosis formation

Discussion

The correct answer is (D). Using a single incision to address both the radius and ulna for ORIF has been shown to lead to a significantly higher incidence of radioulnar synostosis thereby severely limiting forearm rotation. Since the loss of forearm rotation can be quite disabling, surgical excision of the synostosis is recommended. The restoration of the radial bow has not been correlated with one

versus two incisions, however it is of critical importance when fixing a radial shaft fracture. The native bow of the radial diaphysis has been found to average 9.3 degrees apex lateral and 6.4 degrees apex posterior in coronal and sagittal planes, respectively. The lack of adequate restoration of the bow has been shown to result in a significant decrease in both forearm rotation and grip strength.

What neurovascular structure is at high risk of injury and must be protected when approaching a proximal one-third radius fracture from either the volar (Henry) or dorsal (Thompson) approach?

1. Posterior interosseous nerve (PIN)

2. Anterior interosseous nerve (AIN)

3. Radial artery

4. Ulnar artery

5. Median nerve

Discussion

The correct answer is (A). The ulna lies subcutaneously throughout its length and is approached almost exclusively through a direct approach between the FCU and ECU. The radius is more often approached via the Henry approach, which utilizes the interval between brachioradialis and pronator teres proximally and between brachioradialis and FCR more distally, however it can also be approached dorsally via the Thompson approach. The Thompson approach utilizes the interval between ECRB and EDC. In either approach, the PIN lies in precarious proximity to the proximal aspect of the radius and is at risk for injury both during surgical dissection as well as during retraction. To protect the PIN when using the Henry approach, the forearm should be supinated and the supinator should be dissected subperiosteally and handled with care to avoid excessive traction on the nerve. With the Thompson approach, the PIN is most easily identified exiting the supinator, and once identified it should be protected.

Objectives: Did you learn...?

radial bow

The importance of the radial bow? Indications for surgical treatment?

Surgical approaches and at-risk structures during exposure?