Elbow/Forearm

Jeffrey J. Peterson

Thomas H. Berquist

Laura W. Bancroft

▪ FRACTURES/DISLOCATIONS: DISTAL HUMERAL FRACTURES

KEY FACTS

Eighty percent of distal humeral fractures occur in children.
Fifteen percent of physeal fractures in children involve the distal humerus.
The mechanism of injury is a fall on the outstretched hand.
Fractures may be flexion or extension injuries. Extension injuries are 10 times more common than flexion injuries.
- Extension fracture: oblique fracture with posterior displacement of the distal fragment
- Flexion fracture: older age group; transverse fracture line; distal fragment anterior
Fractures are usually obvious on anteroposterior (AP) and lateral radiographs. Computed tomography (CT) with coronal and sagittal reformatting is helpful for evaluating subtle injuries. Magnetic resonance imaging (MRI) is useful for physeal fractures in young children.
Treatment: closed reduction.
Complications: neurovascular injury, premature physeal closure, arthrosis, malunion, nonunion.

FIGURE 7-1. Distal humeral fracture. Lateral (A) and anteroposterior (AP) (B) radiographs show a non-displaced supracondylar fracture.

FIGURE 7-2. Supracondylar fracture. Lateral radiograph (A) does not depict a supracondylar fracture line, but the capitulum lies posterior to the anterior humeral line (black line), indicating a supracondylar fracture. The anterior humeral line should intersect the midcapitellum. There is also a positive posterior fat pad sign (arrow). Lateral radiograph (B) in another patient depicts a joint effusion with subtle supracondylar fracture associated with dislocation of the radial head.

SUGGESTED READING

Anderson SE, Otsuka NY, Steinbach LS. MR imaging of pediatric elbow trauma. Semin Musculoskel Radiol. 1998;2:185-198.

Kinik H, Atalar H, Mergen E. Management of distal humeral fractures in adults. Arch Orthop Trauma Surg. 1999;119:467-469.

Murphy BJ. MR imaging of the elbow. Radiology. 1992;184:525-529.

Neviaser RJ, Resch H, Neviaser AS, Crosby LA. Proximal humeral fractures: pin, plate, or replace. Instr Course Lect. 2015;64:203-214.

▪ FRACTURES/DISLOCATIONS: EPICONDYLAR FRACTURES

KEY FACTS

Avulsion fractures of the epicondyle are common in children.
The injury is common in throwing athletes, specifically pitchers.
The medial epicondyle is particularly vulnerable between ages 9 and 14 years.
Mechanism of injury is varus and valgus forces. Medial epicondylar fractures are common; lateral epicondylar fractures are rare.
Displaced medial epicondylar fragments may be trapped in the joint.
Routine radiographs are usually adequate for diagnosis. MRI is useful for subtle undisplaced fractures and associated soft tissue injuries.
Treatment: closed reduction for undisplaced fractures; pinning of displaced (>3 mm) fractures.
Complications: fragment entrapped in joint, instability.

FIGURE 7-3. Anteroposterior (AP) radiograph of the elbow in a young pitcher with an avulsed medial epicondyle (arrow).

SUGGESTED READING

Larson RL. Epiphyseal fractures in the adolescent athlete. Orthop Clin North Am. 1973;4:839-851.

Stevens MA, El-Khoury GY, Kathol MH et-al. Imaging features of avulsion injuries. Radiographics. 1999;19(3):655-672.

▪ FRACTURES/DISLOCATIONS: ADULT DISTAL HUMERAL FRACTURES

KEY FACTS

The distal humerus consists of medial and lateral columns with the trochlea between the two columns.
The mechanism of injury is trochlear impaction into the humeral articular surface with flexor and extensor muscles causing displacement of the epicondyles.
Fractures may be nonarticular, involve one condyle, or have a “T” or “Y” configuration with varying degrees of comminution.
Treatment: internal fixation commonly required.
Routine radiographs are usually diagnostic. CT with coronal and sagittal reformatting is important for operative planning.
Complications: poor reduction, exuberant callus, reduced range of motion, arthrosis, nonunion (2% to 10%), nerve compression (15%), and postoperative infection.

FIGURE 7-4. Anteroposterior (AP) radiograph demonstrates the medial and lateral columns (black lines) with the trochlea (T) between the columns. Fractures may be extra-articular (1), across both columns (2), or intra-articular (3), involving one or both columns.

FIGURE 7-5. Adult distal humeral fracture patterns. (A) Extra-articular. (B) One condyle. (C) Both condyles. (D) and (E) Both condyles with comminution.

FIGURE 7-5. (continued)

FIGURE 7-6. (A) Anteroposterior (AP) radiograph of a lateral column fracture entering the margin of the trochlea (arrowheads). (B) Coronal reformatted computed tomography (CT) of an intra-articular “T” fracture.

FIGURE 7-7. Computed tomography (CT) images of a lateral column fracture reformatted in the coronal (A) and (B) sagittal planes.

SUGGESTED READING

Helfet DL, Kloen P, Anand N, et al. Open reduction and internal fixation of delayed unions and nonunions of fractures of the distal part of the humerus. J Bone Joint Surg. 2003;85A:33-44.

Ring D, Jupiter JB. Complex fractures of the distal humerus and their complications. J Shoulder Elbow Surg. 1999;8:85-97.

▪ FRACTURES/DISLOCATIONS: CAPITELLAR FRACTURES

KEY FACTS

Capitellar fractures account for 1% of elbow injuries.
Fractures may involve the entire capitellum or the articular surface, or be comminuted and involve the radial head.
Mechanism of injury: direct blow or fall on the outstretched hand with force transmitted from the radius to the capitellum.
Subtle fractures may present with a positive fat pad sign and may require CT or MRI for detection.
Treatment: Loose fragments may require removal. K-wire fixation of large fragments may be necessary in certain cases.

FIGURE 7-8. Lateral view of the elbow demonstrates a capitellar fracture (arrow) and displaced fat pad (open arrow).

SUGGESTED READING

Fowles JV, Dassab MT. Fractures of the capitellum humeria. J Bone Joint Surg. 1975;56A:794-798.

▪ FRACTURES/DISLOCATIONS: FRACTURES OF THE PROXIMAL RADIUS

KEY FACTS

Fractures of the radial head and neck are common, accounting for one-third of elbow fractures. Fractures are categorized as three types on the basis of displacement or comminution of the radial head or neck. Type I, undisplaced (<2 mm) head or neck fracture; Type II, displaced head or neck fracture; Type III, comminuted head or neck fracture.
Mechanism of injury: fall on the outstretched hand with the elbow partially flexed and pronated.
Associated elbow, forearm, and wrist injuries may be present.
Routine radiographs may be normal, except for a positive fat pad sign. Follow-up in 10 to 14 days may demonstrate the fracture. MRI or CT may be required for detection of subtle fractures and for operative planning with complex fractures.
Treatment: Undisplaced fractures are treated with closed reduction. Displaced or comminuted fractures may require internal fixation, resection, or arthroplasty.
Complications include associated ulnar fracture, heterotopic ossification, instability, and arthrosis.

FIGURE 7-9. Fat pad sign. (A) Normal position of the fat pads. Anteroposterior (AP) (B) and lateral (C) radiographs of a radial head fracture with displaced fat pads on the lateral view (arrows).

FIGURE 7-9. (continued)

FIGURE 7-10. Computed tomography (CT) images in the sagittal plane (A, B) demonstrate a minimally displaced comminuted radial head fracture (arrows) with associated capitellar fragments (open arrow).

SUGGESTED READING

Corbett RH. Displaced fat pads in elbow trauma. Injury. 1978;9:297-298.

Geel CW, Palmer AK. Radial head fractures and their effect on the radioulnar joint: a rationale for treatment. Clin Orthop. 1992;275:79-84.

▪ FRACTURES/DISLOCATIONS: ULNAR FRACTURES

KEY FACTS

The ulna is susceptible to trauma because of its superficial location.
Mechanism of injury: direct blow after fall on the flexed elbow.
Most fractures are intra-articular.
Triceps fascia disruption leads to significant displacement and articular deformity.
Routine radiographs are usually diagnostic. The lateral view is most useful.
Treatment: Joint congruity must be restored, which usually requires internal fixation for displaced fractures.
Complications: Instability, decreased range of motion (3% to 50%), articular deformity and arthrosis, ulnar neuropathy (10%), and nonunion (5%).

FIGURE 7-11. (A) Lateral view of the elbow shows a displaced olecranon fracture. (B) Fractures were internally fixed using plate and screw fixation.

SUGGESTED READING

Rettig AC, Waugh TR, Evanski PM. Fracture of the olecranon: a problem of management. J Trauma. 1979;19:23-28.

▪ FRACTURES/DISLOCATIONS: CORONOID FRACTURES

KEY FACTS

Isolated coronoid fractures are uncommon. There are three categories of fracture. Type I: small avulsion of the coronoid tip. Type II: fracture involves 50% of the coronoid, but does not extend to the base. Type III: fracture of the coronoid base.
Coronoid fractures are seen most commonly with posterior dislocations.
Recurrent dislocation is common after coronoid fracture/dislocation.
Displaced fractures can be detected on radiographs. The lateral view is most useful. CT may be required for detection of undisplaced fractures.
Treatment: Closed reduction is adequate in most cases.
Complications: instability, arthrosis, and recurrent dislocation.

FIGURE 7-12. Lateral radiograph demonstrates the locations of Types I to III coronoid fractures (A). Lateral radiograph of the elbow (B) depicts a posterior dislocation of the elbow with a small avulsion fracture of the coronoid process (arrow) (Type II).

SUGGESTED READING

Doornberg JN, Ring D. Coronoid fracture patterns. J Hand Surg Am. 2006;31(1):45-52.

Regan W, Morrey BF. Fractures of the coronoid process of the ulna. J Bone Joint Surg. 1989;71A:1348-1354.

▪ FRACTURE/DISLOCATIONS: ELBOW DISLOCATIONS

KEY FACTS

Dislocation classifications refer to the position of the dislocation.
Most elbow dislocations are posterior and involve both the radius and the ulna.
The mechanism of injury is a fall with the elbow extended.
Anterior, medial, and lateral dislocations are uncommon.
Associated injuries include coronoid, radial head, epicondylar fractures, and neurovascular injuries.
Postreduction CT imaging is important to fully assess the joint space and associated fractures.
Complications include arthrosis, instability, decreased range of motion, neurovascular injury, and extensive heterotopic ossification.

FIGURE 7-13. Lateral radiograph of the elbow depicting a posterior dislocation.

SUGGESTED READING

Koyle SG. Posterior dislocations of the elbow. Clin Orthop. 1991;269:201.

O’Driscoll SW, Morrey BF, Korinek S, et al. Elbow subluxations and dislocations: a spectrum of instability. Clin Orthop. 1992;280:186-197.

Pugh DMW, Wild LM, Schemitsch EH, et al. Standard surgical protocols for treatment of elbow dislocations with radial head and coronoid fractures. J Bone Joint Surg. 2004;86A:1122-1130.

▪ FRACTURES/DISLOCATIONS: MONTEGGIA FRACTURES

KEY FACTS

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