Elbow Fractures

The elbow joint consists of the humeroulnar, humeroradial, and proximal radioulnar joints. Elbow stability is maintained by a combination of static and dynamic constraints. Elbow fractures are challenging to treat because the articular surfaces must be restored perfectly and associated soft tissue injuries must be recognized and appropriately managed. Most elbow fractures are best treated operatively with restoration of normal bony anatomy and rigid internal fixation and repair and/or reconstruction of the collateral ligaments. Advanced imaging, improved understanding of the complex anatomy of the elbow joint, and improved fixation techniques have contributed to improved elbow fracture outcomes.

Key points

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Most fractures about the elbow are treated with open reduction and internal fixation and aggressive postoperative mobilization.
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Extra-articular distal humerus fractures can be treated by a variety of approaches. Complex intra-articular distal humerus fractures are best managed with open reduction and internal fixation using medial and lateral plates using an olecranon osteotomy to facilitate articular reconstruction.
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The coronoid, although small, plays an important role in elbow stability. Anteromedial coronoid facet fractures are difficult to diagnose. If treated inappropriately, varus posteromedial instability may result.
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The treatment of Mason III radial head fractures is controversial; however, good outcomes may be achieved with rigid internal fixation with or without bone grafting and/or collateral ligament repair or reconstruction.
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Elbow ulnar collateral ligament and lateral collateral ligament injuries commonly occur in conjunction with elbow fractures. These soft tissue injuries should be managed with surgical repair or reconstruction. Restoration of stability is as important as anatomic fracture repair.

Anatomy of the elbow joint

The brachial artery and median nerve cross the elbow joint anteriorly, and the radial nerve crosses from the posterior aspect of the humerus through the anterolateral musculature as it passes across the joint. The ulnar nerve curves under the medial epicondyle into the cubital fossa in close proximity to bone and is thus exposed to compromise with elbow fractures and dislocations.

Careful neurovascular examination is mandatory when examining patients with suspected elbow injuries. The posterior interosseus branch of the radial nerve enters the supinator muscle distal to the annular ligament and is at risk when the radial neck is fractured. The ulnar nerve is easily palpated in the cubital fossa and is vulnerable in distal humerus fractures and proximal ulna fractures, especially in fracture-dislocations. The median nerve has better protection due to surrounding soft tissue but may be injured in distal humerus fractures, specifically supracondylar fractures in children.

The elbow collateral ligaments are pivotal to elbow stability. The anterior band of the medial collateral ligament (ulnar collateral ligament [UCL]) originates from the inferolateral aspect of the medial epicondyle and inserts on the sublime tubercle of the ulna. The UCL is the primary stabilizer against valgus forces. The lateral ligament complex consists of the radial collateral ligament and lateral UCL (LUCL). The ligaments weave into the annular ligament, which encases the radial head. The LUCL and radial collateral ligament originate from the isometric center of the elbow joint on the distal aspect of the lateral epicondyle. The fibers of the LUCL insert distally on the supinator crest of the ulna. The LUCL is the primary varus stabilizer of the elbow joint.

The bony architecture of the elbow joint is complex, which, in the setting of trauma, can create several challenges. The distal humerus consists of medial and lateral columns. The medial column supports the trochlea, which articulates with the ulna. The lateral column supports the spherical capitellum, which articulates with the concave radial head. The lesser sigmoid notch articulates with the radial head and facilitates rotation of the forearm. The significance of the coronoid process as the main anterior buttress cannot be overstated, because it plays a critical role in elbow stability.

The joint capsule also contributes significantly to elbow stability. Anteriorly, the joint capsule is taut in extension and the posterior capsule is taut in flexion. Posttraumatic thickening of the capsule contributes significantly to elbow stiffness. Postoperative rehabilitation protocols should focus on aggressive elbow and forearm range of motion.

Distal humerus fractures

Distal humerus fractures are associated with high-energy injuries in young men and lower energy falls in older, osteoporotic women. Distal humerus fractures can be divided into extra-articular, partial intra-articular, and intra-articular ( Fig. 1 ). Nonoperative treatment can be attempted in minimally displaced fractures or if the patient is noncompliant or medically unfit for surgery. However, the risk of elbow stiffness increases with prolonged immobilization, and operative treatment with open reduction and plate fixation is usually recommended.

Plate fixation is the most commonly used fixation method for distal humerus fractures, and double plating is preferred because it neutralizes the rotational forces. An extensive posterior approach with or without olecranon osteotomy is the most commonly used approach to treat distal humerus fractures. The ulnar nerve should be identified and protected throughout such procedures. The paratricipital approach is well suited for extra-articular and simple intra-articular fractures. In complex intra-articular fractures, an olecranon osteotomy can be performed to visualize the posteroinferior aspects of the joint and allow for unimpeded placement of hardware ( Fig. 2 ). Several olecranon-sparing approaches have also been described that preserve the integrity of the olecranon. However, the latter necessitate that the medial and/or lateral ligament is released, and these structures must be restored following fixation.

A subset of distal humerus fractures are the coronal shear fractures ( Fig. 3 ). The coronal shear fragment is very difficult to address from the posterior approach and should be addressed from a separate lateral or medial interval for anatomic reduction. The fragment can be fixed through a posterolateral plate or with isolated headless compression or countersunk screws ( Fig. 4 ).

The rate of complications and secondary surgery is high following distal humerus fractures. ^, Ulnar neuritis is a common complication and evaluation of the ulnar nerve following fixation is important. If there is a risk of hardware irritation or instability of the ulnar nerve in its sulcus, the nerve should be transposed anteriorly. The latter should be tested intraoperatively by passively flexing and extending the elbow. However, the ulnar nerve should not be routinely transposed. Furthermore, the risk of heterotopic ossification is high following these injuries, especially following high-energy injuries. Prophylaxis with indomethacin should be considered in severe cases. Patients should be carefully counseled on the risk of elbow stiffness, ulnar neuritis, and hardware-related problems that may require secondary surgery.

Fractures of the medial epicondyle

Isolated fractures of the medial epicondyle are uncommon and associated with adolescent boys. The fracture is the result of excess valgus force and is an avulsion fracture of the flexor-pronator mass that inserts on the medial epicondyle. The injury is prevalent among adolescent baseball pitchers and presents as an epiphysiolysis.

Displacements of less than 5 mm are commonly treated nonoperatively. Those fractures with greater than 5 mm of displacement should be treated with open reduction and internal fixation (ORIF). Screw fixation is preferred.

Both the insertion of the UCL and the activities of the patient must be considered when evaluating medial epicondyle fractures. Because the UCL origin detaches with the avulsion fragment, injuries with as little as 2 mm may result in elbow instability in throwing athletes. Operative treatment restores native function of the UCL. Fixation with 2 isolated screws often provides adequate stability with high union rates and excellent outcomes. Operative fixation should be considered in throwing athletes with medial epicondyle fractures with as little as 2 mm of displacement.

Radial head fractures

Radial head fractures are the most common elbow fracture and constitute one-third of all elbow injuries. The radial head is an important restraint to valgus forces in concert with the UCL. Biomechanical studies have shown that the radius contributes significantly to force transmission in the extended elbow because 40% of total force is transmitted over the radiocapitellar joint, with peak loads shown in supination. ^,

Radial head fractures occur as isolated bony injuries or in conjunction with other stabilizing structures that result in fracture-dislocations of the elbow. Radial head fractures are most commonly caused following valgus trauma. ^, Therefore, the integrity of the UCL must also be assessed in the setting of a radial head fracture.

The Mason classification is commonly used to classify radial head fractures with types I through IV. Computed tomography (CT) evaluation is recommended, especially to evaluate the articulation of the proximal radioulnar joint. Minimally displaced fractures that do not cause impairment of rotation may be treated nonoperatively and patients can start immediate mobilization. Failure to initiate early active range of motion can cause elbow stiffness. Larger fragments that interfere with rotation can be treated with open reduction and isolated screw fixation ( Fig. 5 ). Mason 3 fractures can be treated with ORIF or radial head arthroplasty. Resection is not recommended because this may result in shortening of the radius, rapid arthritic development, and chronic wrist pain. Whether Mason 3 fractures should be treated with ORIF or radial head arthroplasty is debated. It is the senior author’s opinion that these fractures can be treated with ORIF as long as the integrity of the UCL is restored, either through primary repair or graft reconstruction. Usually, plate fixation is necessary in addition to isolated screws ( Fig. 6 ). The patients should be informed that plate removal may be necessary to restore functional rotation. However, ORIF avoids the potential disadvantages associated with radial head arthroplasty, such as overstuffing and osteolysis of the proximal radius, and does not preclude its future use.