Radial head and neck fractures in adults

INTRODUCTION — Radial head and neck fractures occur frequently, most often following a fall onto an outstretched hand. Nondisplaced fractures can be managed by knowledgeable, primary care physicians; orthopedic referral is needed for more complex fractures.

The presentation, evaluation, and basic management of radial head and neck fractures are reviewed here. The management of pediatric elbow fractures and other upper extremity injuries in adults and children are discussed separately:

●Pediatric elbow fractures (see "Elbow injuries in active children or skeletally immature adolescents: Approach" and "Elbow anatomy and radiographic diagnosis of elbow fracture in children" and "Supracondylar humeral fractures in children" and "Evaluation and management of condylar elbow fractures in children")

●Adult elbow fractures and other injuries (see "Evaluation of elbow pain in adults" and "Elbow tendinopathy (tennis and golf elbow)" and "Elbow fractures and dislocation in adults" and "Midshaft ulna and radius fractures in adults")

EPIDEMIOLOGY AND RISK FACTORS — Radial head and neck fractures are common and are present in about 30 percent of all elbow fractures [1,2]. They represent between 1.7 and 5.4 percent of all fractures in adults [3].

Some studies describe a male predominance with a ratio of 2:1, but others describe equal distribution between genders [4,5]. On average, fractures in men occur seven years earlier than in women [5]. Radial head fractures occur throughout adulthood; the mean age at the time of injury is approximately 45 years. Fractures of the radial neck occur most often in children and are much less common in adults.

FUNCTIONAL ANATOMY — The radial head and neck comprise the most proximal portion of the radius (figure 1 and figure 2 and figure 3). The radial head lies at the proximal end. It is disk-shaped with a flattened end that articulates with the capitellum of the humerus proximally. The radial head also articulates with the lesser sigmoid notch of the ulna medially. Just distal to the head but proximal to the tuberosity is the radial neck, which is narrower than the head and slightly concave.

Articular cartilage covers nearly the entire circumference of the radial head. The radial head derives its blood supply from both intraarticular and intraosseous sources [6]. This dual blood supply likely contributes to its resistance to osteonecrosis even following displaced fractures.

The elbow consists of three separate bony articulations: the radiocapitellar, ulnotrochlear, and proximal radioulnar joints. All three are located within a single joint capsule. Together they form a modified hinge joint. The ulnotrochlear and radiocapitellar joints enable flexion and extension of the elbow, and allow for the transmission of forces from the forearm to the humerus. The radiocapitellar joint, along with the medial collateral ligament or ulnar collateral ligament, provides a significant degree of valgus stability, especially with the elbow in extension.

In conjunction with the distal radioulnar joint, the proximal radioulnar joint allows for pronation and supination. The strong annular ligament of the radius holds the radial head in the lesser trochlear (radial) notch of the ulna to allow for smooth rotation throughout pronation and supination.

Although the posterior interosseous nerve (a branch of the radial nerve) runs through the supinator muscle just distal to the radial neck and is anatomically at risk of injury with radial head and neck fractures, in fact the nerve is rarely injured.

CLASSIFICATION — No ideal fracture classification system exists for radial head fractures, but a modified Mason classification is used most often. The system was originally based upon radiographic appearance alone but was modified to include a fourth category of fractures with associated elbow dislocations [2,7]. Approximately two-thirds of radial head fractures are Mason type I [5].

The Mason classification is as follows:

●Mason type I – Nondisplaced fractures (displacement ≤2 mm) (image 1)

●Mason type II – Displaced fractures >2 mm

●Mason type III – Comminuted fractures (image 2)

●Mason type IV – Radial head fracture with associated elbow dislocation (image 3)

MECHANISM OF INJURY — The most common mechanism for radial head and neck fractures is a fall onto an outstretched hand leading to axial impaction of the radius on the capitellum (figure 4). The severity of the fracture is generally proportional to the force applied to the arm. Injuries suffered as a result of sports and falls from a height often entail more severe fracture patterns. Fractures can also occur due to direct trauma or from a radial head dislocation in association with a Monteggia fracture (ulnar fracture with radial head dislocation) or true elbow dislocation.

Concomitant fractures, dislocations, and soft tissue injuries are common with more severe fractures (Mason types II and III) but uncommon with Mason type I fractures [5,8-10]. Detecting associated injuries is important for proper management. Injuries to structures about the elbow, including the medial collateral ligament, interosseous ligament, coronoid process, and distal radioulnar joint, are particularly important and likely to affect treatment. (See 'Functional anatomy' above.)

CLINICAL PRESENTATION AND EXAMINATION — Patients with radial head or neck fractures typically present within 48 hours following a fall onto an outstretched hand or direct elbow trauma [5]. Nevertheless, subacute and chronic injuries do occur. A history of a dislocation with spontaneous relocation increases the likelihood of a medial collateral ligament (MCL) or coronoid process injury.

A screening neurovascular examination should be performed. Although rarely injured, the posterior interosseous nerve can be tested by having the patient extend their thumb. Techniques for performing a screening neurologic examination of the upper extremity are described separately. (See "Midshaft humerus fractures in adults", section on 'Symptoms and examination findings'.)

A fracture of the proximal radius should be considered in any patient with pain, tenderness, or swelling over the lateral elbow, or with decreased elbow motion, following any type of trauma. Ipsilateral wrist or forearm pain may be a sign of concomitant injury and warrants radiographic investigation.

Inspect the elbow and wrist for obvious deformity or bruising. Significant ecchymosis is most often a sign of soft tissue damage.

Palpate the radial head for crepitus and tenderness while the forearm is gently pronated and supinated. Based upon clinical experience, joint tenderness over the radial head is a sensitive sign of injury. Carefully palpate the forearm and elbow for tenderness along the interosseous membrane and MCL. Examine the wrist and forearm for focal tenderness suggesting other injuries.

Assess the elbow's range of motion (both flexion-extension and supination-pronation) as permitted by the patient's pain (table 1). Fracture fragments may sometimes block forearm rotation, but in the acute setting motion is usually limited by a painful hemarthrosis, not a true mechanical block. Management of the elbow with reduced motion is discussed below. (See 'Limited joint motion' below.)

DIAGNOSTIC IMAGING — Obtain standard anterior-posterior (AP) and lateral x-rays of the elbow (image 4) in all patients with a suspected radial head or neck fracture. Inspect these x-rays for the following:

●Fracture line (image 5)

●Abnormal bony alignment (image 6)

●Angulation, depression, comminution, or displacement of the radial head or neck

●Fat pads (image 7 and figure 5)

●Small bone fragments within the joint

Elevated anterior and posterior fat pads (so-called "sail sign") due to blood distending the joint capsule may be the only sign of an occult, nondisplaced radial head fracture. Fractures of the radial neck are less likely to produce elevated fat pads as the fracture may be entirely extraarticular. A posterior fat pad sign is abnormal and more specific for fracture [11,12]. A small oval anterior fat pad may be a normal finding, but displacement of the fat pad away from the bone in the setting of acute trauma suggests a joint effusion. Bone fragments within the joint suggest a chip fracture of the capitellum.

Clinicians can perform a radiocapitellar, or Greenspan, view to better characterize a fracture or when a fracture is suspected clinically but not apparent on standard views. The Greenspan view is obtained by angling the beam 45 degrees cephalad with the elbow in neutral position (image 8) [13].

CT scanning is most useful in preoperative planning and is not indicated in the acute setting. MRI is used primarily for detecting occult fractures but is rarely needed. Clinical suspicion based upon mechanism and examination findings are typically all that are needed to treat non-displaced fractures that would only be seen on MRI.

DIAGNOSIS — Fracture of the radial head or neck is diagnosed radiographically. In the large majority of cases, plain radiographs are sufficient, including anteroposterior and lateral views of the elbow. Elevated anterior and posterior fat pads due to blood distending the joint capsule can develop from elbow trauma and suggest an occult, nondisplaced radial head fracture if plain radiographs are negative and the patient is tender over the radial head. Patients with a radial head or neck fracture typically present soon after a fall onto an outstretched hand or direct elbow trauma complaining of elbow pain, swelling, and limited motion. Examination reveals focal tenderness in the area of the radial head.

INDICATIONS FOR ORTHOPEDIC REFERRAL — Open fractures, fracture dislocations, and all fractures associated with a neurologic deficit (eg, median, radial, or ulnar nerve injury) or circulatory compromise (brachial artery injury) require emergent surgical consultation. However, radial head and neck fractures are rarely associated with such complications.

Orthopedic consultation should be obtained within several days of the injury for all displaced radial head and neck fractures, including Mason types II and III. Elbow fracture/dislocations (Mason type IV) require urgent orthopedic consultation. The Mason classification is described above. (See 'Classification' above.)

Nondisplaced (Mason type I) fractures involving the radial head or both the radial head and neck can generally be treated by a primary care physician once it has been determined that no mechanical block to elbow flexion exists. A mechanical block suggests a displaced bone fragment, which requires orthopedic intervention. Assessment for a mechanical block is discussed below. (See 'Limited joint motion' below.)

INITIAL MANAGEMENT

Goals of care — The goals of treatment for a radial head fracture are to promote fracture healing while maintaining elbow range of motion and hand and arm strength. Although randomized trials to support this approach are lacking, many experts believe that early mobilization is the most important factor for maintaining normal elbow motion in patients with nondisplaced or minimally displaced radial head fractures [14-17].

Basic treatment — Initial treatment depends upon the fracture type and the patient's symptoms [14]. Nondisplaced (Mason type I) radial head fractures with full motion can be treated with a sling for comfort for 24 to 48 hours. A posterior splint may be applied in the acute setting but should not be used for more than a day or two [16]. Range of motion exercises should be started as early as possible. Ice is applied during the first 24 hours. Acetaminophen or nonsteroidal antiinflammatory drugs (NSAIDs) are generally adequate for acute pain control; opioids are usually unnecessary.

Range of motion exercises consist primarily of extension and flexion of the elbow with the emphasis on fully straightening and flexing the joint. Additionally, the patient performs pronation and supination with their arm at their side and their elbow held at 90 degrees. In this position, the patient simply rotates the forearm so the palm faces up and then down.

In the acute setting, clinicians can treat patients with displaced or complex fractures (Mason types II or III) with a sling or posterior splint for comfort, ice, analgesics, and orthopedic referral within several days for further care. The treatment of Mason type II radial head fractures remains controversial and should be determined by an orthopedist. The majority of Mason types III and IV radial head fractures require operative intervention, often with radial head resection and prosthetic replacement.

Limited joint motion — Radial head fractures associated with restricted elbow flexion-extension on presentation need further evaluation. Most often, limited mobility is due to the pain of a distended joint capsule from hemarthrosis, but occasionally a fracture fragment in the joint mechanically blocks motion.

Aspiration of the hemarthrosis and injection of local anesthetic into the joint provide substantial pain relief and enable the clinician to perform a better evaluation of joint motion (figure 6) [18,19]. A persistent mechanical block requires orthopedic consultation and intervention.

Dislocation — Immediate reduction is critical in patients who present with a radial head or neck fracture associated with an elbow dislocation. The longer the elbow is allowed to remain dislocated, the more difficult the reduction and the greater the risk of avascular necrosis [20]. If an orthopedic surgeon is not immediately available, the treating physician must reduce a posterior elbow dislocation, even when associated fractures are present.

Ideally, reduction is performed in a monitored environment with the ability to give intravenous sedation and analgesia. The performance of procedural sedation is discussed separately. (See "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications".)

One traditional way to reduce a posterior elbow dislocation consists of applying longitudinal traction to the supinated forearm, while an assistant provides counter traction to the humerus. The elbow is held in slight flexion. The clinician then applies moderate steady force to the posterior tip of the olecranon using the thumb while the opposite hand continues to apply steady traction to the forearm. If this approach is unsuccessful, the clinician can use the hand applying traction to gently flex the patient's elbow [20].

If the reduction must be performed without assistance, a gurney or chair can be used to brace the humerus, while the clinician applies traction to the forearm with one hand and presses on the olecranon with the thumb of the opposite hand [21-23].

Once the joint is reduced (often with a satisfying clunk), the elbow is taken through its full range of motion (including full extension, flexion, pronation, and supination) to assess stability. Stability against valgus and varus stress should also be assessed with the elbow in near full extension.

If the elbow loses reduction during this evaluation, note the position in which this occurred. Repeat the reduction maneuver and splint the elbow in 90 degrees of flexion with the forearm in neutral. Once the elbow is reduced, obtain repeat radiographs with the elbow splinted to confirm that the elbow is in fact reduced. Orthopedic consultation within 24 hours is necessary for cases in which the elbow is successfully reduced. If the elbow cannot be reduced, emergent orthopedic consultation is mandatory.

FOLLOW-UP — Patients with nondisplaced radial head or neck fractures are reassessed weekly for three weeks to confirm continued improvement. Encourage patients to perform active flexion-extension and pronation-supination exercises, as early motion is the most important factor in speeding recovery and maximizing long-term joint mobility [14-17].

If the patient has increasing pain or does not show improvement in range of motion, obtain repeat radiographs to assess fracture stability and look for other injuries. Immediate referral to an orthopedist is necessary if a displaced fracture or concomitant injury is detected. If such conditions are absent, the patient may need closely supervised physical therapy. Despite these cautions, conservative treatment is successful in the great majority of cases.

Follow-up care for patients with displaced (ie, Mason II to IV) fractures is determined by the orthopedic surgeon and the timing of operative intervention.

PROGNOSIS AND COMPLICATIONS — The large majority of patients with nondisplaced fractures of the radial head or neck have excellent outcomes [24]. The most common complication from radial head and neck fractures is decreased elbow range of motion, particularly loss of full extension. Early, active range of motion exercise is the most important factor in mitigating this complication.

Elbow instability is infrequent but can occur with concomitant injuries to the lateral or medial collateral ligaments or the coronoid process. These inevitably require reconstruction, and specialized orthopedic care should be sought. (See 'Indications for orthopedic referral' above.)

Patients reporting continued pain at the elbow may have occult soft tissue injuries, a capitellar fracture, or an osteochondral lesion. Traumatic osteoarthritis is another cause of elbow pain following fracture of the radial head; the likelihood of osteoarthritis increases with the severity of the fracture.

Wrist pain may occur, possibly due to unrecognized injuries to the carpal bones, interosseous membrane, distal radioulnar joint, triangular fibrocartilage complex, or other structures.

RETURN TO SPORT OR WORK — Patients may return to sports or heavy physical labor once the injured elbow has recovered painless full range of motion and the arm has regained normal strength, which typically requires about 8 to 12 weeks with nonoperative treatment. Return to sports and work is generally delayed by two to four additional weeks in patients who undergo operative fixation.

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of definitive fracture management".)

●(See "General principles of acute fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Fractures of the skull, face, and upper extremity in adults" and "Society guideline links: Acute pain management".)

SUMMARY AND RECOMMENDATIONS

●Epidemiology – Radial head and neck fractures are common in adults of all ages. More severe fracture types are often associated with other injuries; isolated nondisplaced fractures can be managed by primary care physicians comfortable with fracture care and typically have excellent outcomes. (See 'Epidemiology and risk factors' above and 'Mechanism of injury' above.)

●Clinical presentation – Suspect fracture of the proximal radius in patients presenting with lateral elbow pain and a history of a fall onto an outstretched hand or direct trauma to the elbow. Presentation typically includes pain, tenderness, and swelling over the lateral elbow, often with decreased elbow motion. (See 'Clinical presentation and examination' above.)

Assessing range of motion of both flexion-extension and pronation-supination is vital in patients with Mason type I radial head fractures. If deficits are identified, further evaluation is needed following hemarthrosis aspiration and local anesthetic injection. (See 'Limited joint motion' above.)

●Indications for orthopedic referral – Immediate orthopedic evaluation is needed for any patient with an open fracture, neurovascular compromise, or fracture dislocation. (See 'Indications for orthopedic referral' above.)

●Importance of immediate reduction of associated elbow dislocation – Immediate reduction is critical in patients who present with a radial head or neck fracture and an elbow dislocation. The longer the joint is allowed to remain dislocated, the more difficult the reduction and the greater the risk of avascular necrosis. (See 'Dislocation' above.)

●Diagnostic imaging – Obtain anteroposterior (AP) and lateral plain radiographs in all patients where a fracture about the elbow is suspected. If no fracture is evident, a radiocapitellar (Greenspan) view may better characterize the radiocapitellar joint. (See 'Diagnostic imaging' above.)

Elevated anterior or posterior fat pads may be the only indication of a radial head fracture; such patients can be treated in the acute setting with either a posterior splint or sling, as if a Mason type I fracture were present.

●Management – Early mobilization is paramount for obtaining good short-term and long-term results. Patients who are slow to progress during rehabilitation may need closely supervised physical therapy. (See 'Initial management' above and 'Follow-up' above.)