Radial Head Fractures: Open Reduction and Internal Fixation

David Ring

INTRODUCTION

The advent of techniques and implants for internal fixation of small fractures (1) coincided with an increasing appreciation of the important contributions of the radial head to the stability of the elbow and forearm (2, 3, 4 and 5). In conjunction with the inadequacy and problems associated with the silicone rubber radial head prostheses (2,6, 7 and 8), it became popular to attempt to save even the most complex fracture of the radial head by operative fixation (9). Early reports of open reduction and internal fixation of fractures of the radial head were very positive, perhaps due to the prevalence in these early series of isolated partial head fractures for which good results would be expected (10, 11, 12, 13, 14 and 15). Some subsequent reports have found that complex fractures of the radial head are prone to early failure, nonunion, and poor forearm rotation after operative fixation (9,16, 17 and 18). Combined with increased availability and use of more predictable metal radial head prosthesis for complex fractures of the radial head (19,20), most surgeons reserve open reduction and internal fixation for fractures with three or fewer large articular fracture fragments of good bone quality with no fragmentation or bone loss (21).

INDICATIONS AND CONTRAINDICATIONS

Historical Background

For most of the last century, excision of the radial head was the only commonly used treatment for fractures of the radial head (22,23) and decision making was simple: excise or do not excise. If excision was elected, the entire head was resected because the results of partial head excision were usually poor (24, 25, 26 and 27). Open reduction and internal fixation became a more viable option with the advent of techniques and implants for the fixation of small fractures and articular fracture fragments in the 1980s (1).

The incidence, severity, and consequences of proximal migration of the radius after excision of isolated fractures of the radial head have long been a source of debate (25). On the other hand, there is agreement on the value of retaining the fractured radial head in the setting of complex combined injury with instability of the forearm or elbow such as an Essex-Lopresti injury (23,28) (radial head fracture and rupture of the interosseous ligament of the forearm) or a terrible triad injury (posterior dislocation of the elbow with fractures of the radial head and coronoid process) (29, 30, 31 and 32). The radial head is increasingly recognized as an important stabilizer of the forearm and elbow (2, 3, 4 and 5,23,29, 30, 31, 32, 33 and 34). Some authors even suggest that ulnohumeral arthrosis after elbow fracture dislocation is accelerated in the absence of a radial head (35).

The initial reports of open reduction and internal fixation of fractures of the radial head focused primarily on isolated fractures involving only part of the radial head (10, 11, 12, 13, 14 and 15). The good results in these series, the popularity
of the new techniques for internal fixation of small fractures, and the increasing recognition of the importance of the radial head led many to emphasize the importance of preserving the native radial head. Unfortunately, subsequent study have reported unpredictable results after internal fixation of more complex fractures of the radial head (9,16, 17 and 18), particularly very comminuted fractures with greater than three articular fragments (9).

Combined with recent improvements in radial head prostheses, the decision making for radial head fractures associated with instability of the forearm or elbow now focuses on fixation versus prosthetic replacement (21). Problems have been reported related to the articulation of a metal radial head implant with native capitellar cartilage, although the majority of these are related to an oversized prosthesis (36). In general, results of prosthetic replacement of the radial head have been quite favorable (19,20,37), making it a useful alternative to open reduction and internal fixation.

Goals of Treatment

Fracture of the radial head can restrict forearm rotation, compromise the stability of the forearm or elbow, and—although relatively uncommonly—cause radiocapitellar arthrosis.

The primary goal of treatment is to ensure forearm rotation. Incongruity of the radial head in the proximal radioulnar joint causes loss of rotation. Painful arthrosis of the proximal radioulnar joint is not usually observed. Long-term data from Sweden support the contention that partial fractures of the radial head that do not restrict forearm rotation are usually consistent with excellent elbow and forearm function no matter the radiographic appearance (38), although some data are at odds with this (13).

Operative fixation can restrict forearm rotation via implant prominence, scarring, or heterotopic bone formation. Some patients with healed, apparently well-aligned fractures of the radial head after operative fixation have substantial loss of motion that is not attributable to implant prominence (9). This may be due to articular incongruities, but—based on observations of my own patients, and some similar observations in the literature (39)—I suspect that many fractures of the radial head are impacted in a way that expands the diameter of the radial head. Healing of the radial head with this deformity might contribute to loss of forearm motion. Loss of ulnohumeral motion is usually related to capsular contracture and only rarely related to interference from displaced fracture fragments.

When the interosseous ligament of the forearm has been torn [the so-called Essex-Lopresti lesion (28) and variants (40,41)], the initial treatment must include restoration of contact between the radial head and capitellum to prevent marked proximal migration of the radius. Although restoration of the radial head does not guarantee good function in this complex injury, failure to restore the radial head will result in a chronic forearm instability that currently had no good solution (42). Attempts to save the radial head at all costs might be unwise in this setting. For instance, many chronic Essex-Lopresti lesions result from failure of attempted operative fixation of the radial head. In this circumstance where the radial head is essential, tenuous fixation of a complex radial head fracture may be inadequate and prosthetic replacement might be preferable.

The circumstance is similar for elbow fracture dislocations. Particularly for unstable elbow injuries such as the terrible triad pattern of elbow fracture dislocation (30), secure reconstruction of the radial head is requisite. If the fracture is too complex to achieve this, then radial head replacement may be preferable. Many partial head fractures are difficult or impossible to repair securely and should also be considered for prosthetic replacement (43). The part of the radial head that is fractured is the critical anterolateral buttress resisting posterior displacement of the elbow (44).

Although radiographic criteria for acceptable alignment of the radial head articular surface are frequently offered (25,32,45,46), there are few data to support them. The oft-repeated 2-mm limit for acceptable articular alignment derived from Knirk and Jupiter’s (47) study of intraarticular distal radius fractures may not apply to the radiocapitellar joint. Although displaced fractures of the radial head are extremely common, radiocapitellar arthritis is an uncommon presenting complaint about which very little has been published (48).

Treatment Rationale According to Injury Pattern

Isolated Partial Radial Head Fractures

Slightly displaced fractures involving part of the radial head do relatively well with nonoperative treatment (38,46,49,50). They rarely block motion, cause pain, or lead to arthrosis. Although radiographic criteria for operative treatment have been suggested, they lack scientific support.

One generally accepted indication for operative treatment of an isolated partial fracture of the radial head is a fracture that blocks forearm rotation. Because it can be difficult to assess forearm rotation in the setting of an acute painful elbow hemarthrosis, it can be useful to aspirate the hemarthrosis and place a local anesthetic in the elbow joint. Alternatively—perhaps preferably—if the patient is evaluated in the office at least 4 or 5 days after injury, there is usually sufficient pain relief to allow a reliable examination. Crepitation with forearm rotation does not seem predictive of problems, provided there is no block to motion, although this deserves further study.

Given that few problems arise with nonoperative treatment [a minimum of 75% good results in long-term follow-up according to a very strict rating scale (50)], the surgeon should not take too much credit for good elbow function after operative treatment of isolated partial fractures of the radial head. Since operative treatment represents an opportunity for several complications, it should be undertaken with care (51).

Isolated fractures of the radial head that are more than slightly displaced are relatively uncommon (approximately 6% to 15% of all radiographically visible partial radial head fractures) and unreliably diagnosed (52). Among this small group of patients, it is uncommon to observe a block to forearm rotation. The surgeon should therefore approach the management of the patient with an isolated partial fracture of the radial head with the understanding that these fractures rarely benefit from operative treatment (53,54).

Partial Radial Head Fracture as Part of a Complex Injury

The treatment rationale for partial radial head fractures that are part of a complex injury pattern is entirely different. Such fractures are usually displaced and unstable with little or no soft-tissue attachments and occasionally some fragments are lost (55). Even a relatively small fracture can make an important contribution to the stability of the elbow and forearm. Usually, the anterolateral aspect of the radial head is fractured, with resultant loss of the anterior buttress of the ulnohumeral joint (44).

While such fractures would seem to be obvious candidates for open reduction and internal fixation because the majority of the head remains intact, they can be very challenging to treat due to fragmentation, the small size of the fragments, lost fragments, poor bone quality, limited subchondral bone on the fracture fragments, and metaphyseal comminution and bone loss (43). Early failure of fixation of these fractures is potentially problematic, particularly in the setting of an Essex-Lopresti injury or a terrible triad fracture dislocation of the elbow. Therefore, many partial head fractures associated with complex injuries may be best treated with prosthetic replacement even though this means removing a substantial amount of uninjured radial head. Open reduction and internal fixation is indicated when stable, reliable fixation can be achieved.

Displaced, partial head fractures are common among patients with posterior olecranon fracture dislocations—the majority of whom are older, osteoporotic women. Some authors believe that radial head excision is acceptable in this setting provided that the ulnohumeral joint is stable (56). In some cases, I have neglected or excised a small partial radial head fracture in this setting, with good results, but I favor retaining the stability and support of radiocapitellar contact in most cases. I believe that a low-energy injury in an older patient is a relatively favorable setting in which to consider neglecting or resecting the radial head, but that retention of the radial head, either with operative fixation or prosthetic replacement, would be preferable in healthy, active patients injured in high-energy injuries.

Fractures Involving the Entire Head of the Radius

Fractures involving the entire head of the radius [type 3 according to the system of Mason (22)] are almost always part of a more complex injury. Some older, low-demand patients are best treated with resection of the radial head without prosthetic replacement, but only if the elbow and forearm are stable. The rare younger patient with an isolated injury involving the entire radial head can also be considered for excision without prosthetic replacement, but retention of the radial head may improve the function and durability of the elbow, particularly with forceful use, although it can be debated whether a metal prosthetic articulating with capitellar cartilage is better than no articulation at all in the long run.

When treating a fracture dislocation of the forearm or elbow with associated fracture involving the entire head of the radius, open reduction and internal fixation should only be considered a viable option if stable, reliable fixation can be achieved. There is a definite risk of both early failure and later nonunion, both of which can contribute to recurrent instability (9). Other factors such as loss of fragments, metaphyseal bone loss, impaction and deformity of fragments (39), and the size and quality of the fracture fragments may make open reduction and internal fixation a less predictable choice. In particular, if there are more than three articular fragments, the rates of early failure, nonunion, and poor forearm rotation may be unacceptable (9). The optimal fracture for open reduction and internal fixation will have three or fewer articular fragments without impaction or deformity, each of sufficient size and bone quality to accept screw fixation, and little or no metaphyseal bone loss.

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