Radial Head Fracture: General Considerations, Conservative Treatment, and Radial Head Resection

Historical Review

The first description of a radial head fracture may be attributed to Beard, who, in 1834, noted the presence of this injury at autopsy. By 1880, Bruns found 21 cases in the literature, but only one of them was a clinical case; the others were anatomic findings. In 1891, Hoffa described two types of radial head fractures, displaced and undisplaced, and he recommended radial head resection as the best treatment. Thomas was the first to describe the mechanism of injury of radial head fractures in 1905: a fall on the outstretched arm, with the hand in pronation to defend against the fall. Lambotte was the first to describe osteosynthesis of a displaced radial head fracture.

With the advancement in understanding of elbow kinematics and the importance of the radial head for stability and load transmission, radial head fractures have become a focus of great interest among surgeons dealing with elbow trauma.

Mechanism of Fracture

A direct blow is an uncommon but recognized cause of radial head fracture. An axial load to the pronated forearm consistently produces a fracture of the most anterior portion of the radial head similar to that seen in clinical experience ( Fig. 37.3 ). Because the head of the radius is eccentric to the central axis of the neck, the posterolateral aspect of the radial head comes into intimate contact with the capitellum during pronation. Other experiments have suggested the determination on whether a coronoid or radial head fracture occurs is based on the degree of elbow flexion. Coronoid fractures are more likely to occur in extension while radial head fractures occur with greater elbow flexion.

Concurrent Fractures About the Elbow

While well recognized to be the major determinant of treatment and outcome, the frequency of associated injuries varies widely based on the sensitivity of assessment and study design. Kodde et al. reported the prevalence of associated injuries in the ipsilateral arm of a nondislocated elbow with radial head fracture to be only 11% and more commonly seen in older patients. On the other hand, Van Riet et al. assessed 333 radial head fractures seen at the Mayo Clinic and observed that the likelihood of associated injuries strongly correlates with the severity of the radial head fracture. The incidence of associated injuries increases from 20% in nondisplaced fractures to 80% in comminuted radial head fractures. The vast majority of these injuries (90%) are fractures about the elbow, mostly articular surface lesions. Approximately 20% of these articular injuries include the distal humerus, whereas in more than 90%, the proximal ulna is involved.

Fractures or cartilage injuries of the capitellum are common, occurring in up to 90% of cases, but are not always appreciated. Undisplaced or minimally displaced fractures may show cartilage injury of the capitellum in only 2% of cases, while in comminuted, displaced radial head fractures, the frequency increases to as much as 25%. Cartilage injuries are difficult to diagnose and should be suspected when there a is block of motion or clicking in the absence of significant fracture displacement. A magnetic resonance imaging (MRI) scan is very helpful in these circumstances. Some patients with posterolateral fracture dislocations of the elbow sustain a posterior impaction fracture of the capitellum, first described in 1955 by Osborne-Cotterill, that may jeopardize elbow stability even after the radial head and ligaments are repaired. This lesion should be identified and addressed if it engages the radial head margin in extension ( Fig. 37.4 ).

Fracture of both the olecranon and the radial head is usually considered to be a variety of the Monteggia fracture and has been analyzed in detail by Scharplatz and Allgower and others (see Chapter 42 ).

According to Van Riet et al., 15% of radial head fractures are complicated by a coronoid fracture, and 15% have an associated elbow dislocation. In fact, the coronoid process is involved in 80% of patients who sustain a radial head fracture as part of an elbow dislocation. This pattern of injury represents one of the variants of acute elbow complex instability. Rineer et al. found that 91% of radial head fractures with loss of cortical contact between the fragments are associated with more complex articular injuries, such as fractures of the coronoid and dislocations.

Bilateral radial head fractures are uncommon and occur in about 1.5% of patients.

Ligamentous Injury at the Elbow

Though often not appreciated, the radial head fracture occurs in about 10% of clinically detected injuries to the medial or lateral collateral ligaments, representing half of all clinically relevant associated injuries. Usually presenting as an elbow dislocation (type IV injury), isolated ligament injuries do occur. An incompetent ulnar collateral ligament may be clinically obvious by an increased valgus position of the forearm under valgus stress, with radiographic opening of the medial ulnohumeral joint ( Fig. 37.5 ). In the past, Arvidsson and Johansson found ligament or capsular disruption by arthrography with various types of radial head fractures. Johansson demonstrated positive arthrographic findings in 4% of type I, 21% of type II, and 85% of type III injuries. Subtle injuries initially unrecognized are later evident when calcification is observable on subsequent radiographs. Wagner reported 24 patients with calcification, and Arner et al. described a 12% incidence of ulnar collateral ligament calcification.

With MRI assessment, some degree of lateral collateral ligament damage was detected by Kaas et al. in 29 of 44 patients with radial head fractures, and Itamura et al. reported a lateral ligament injury in 18 of 24 such patients. However, the clinical relevance of these findings was insignificant in the vast majority of cases at subsequent follow-up. The available information shows that some degree of soft tissue injury is commonly present after an apparent isolated radial head fracture, and its incidence is proportional to the comminution of the fracture. However, these injuries are seldom clinically relevant and tend to heal without consequences.