04-Apr-2014 12:34 04-Apr-2014 12:34Date: Date: 9 9Version: Version: Joseph BernsteinAuthor:
Musculoskeletal Medicine for Medical Students
Radial Head fractures
Table of Contents
1 Description
2 Structure and function
3 Patient presentation
4 Clinical evidence
5 Epidemiology
6 Differential diagnosis
7 Red flags
8 Treatment options and outcomes
9 Risk factors and prevention
10 Miscellany
11 Key terms
12 Skills
Radial Head fractures
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1 Description
Radial head fractures are the most common type of elbow fractures in adults. Perhaps counter to
intuition, fractures of the radial head (which is part of the elbow) typically occur after a fall on an
outstretched hand. The impact from the fall drives the radius proximally into the humerus, causing an
injury at the elbow.
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2 Structure and function
The radial head articulates with both the capitellum of the humerus and the ulna. The radial head is
concave, matching the convex surface of the capitellum of the humerus. The radial head translates on
the capitellum during elbow flexion-extension, and pivots around the central axis of the ulna during
supination-pronation. Just distal to the radial head lies the annular ligament, which holds the radius to
the ulna. This ligament allows for rotation as well as some translation, as the central axis of the radius is
not perfectly cylindrical (and thus during pronation, the radius translates). The radial head also
ultimately supports the carpus, as it is the base on which the radius itself is supported.
xray of normal elbow showing radial articulation
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3 Patient presentation
Patients with an injury to the radial head typically present with a history of a fall on an outstretched
hand, or, following higher energy trauma, elbow dislocation. Pain, effusion over the elbow, and limited
range of motion at the elbow and forearm are common symptoms. There is typically localized
tenderness over the radial head on palpation; passive rotation of the forearm is also painful.
Intra-articular bleeding from the fracture may produce a palpable effusion. Aspiration of the effusion
may assist with diagnosis and provide pain relief, thereby allowing faster and more effective
clinical phone of ASPIRATION of radial fx hemarthrosis
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4 Clinical evidence
Radiographs must be obtained in the case of suspected elbow fracture; standard anteroposterior (AP)
and lateral films of the elbow and of the wrist usually suffice. The distal radio-ulnar joint should be
assessed on the lateral film for dislocation. A fracture of the radial head with concomitant dislocation of
the distal radio-ulnar joint is called an Essex-Lopresti fracture.
Oblique views with the forearm in neutral rotation, called Greenspan views, show the radiocapitellar
articulation and may be useful in the case of a suspected fracture that is not visible on AP or lateral
films. Additionally, a positive fat pad sign on a lateral view indicates fluid in the joint, which in the acute
setting is usually blood suggestive of a fracture.
xray of fat pad sign for radial head fx
CT scanning may be used for preoperative planning, especially in the case of fragment displacement or
MRI may be used to assess for possible osteochondral injuries of either the radial head itself or, more
commonly, of the capitellum. This is usually reserved for patients with persistent pain after a period of
Although radial head fractures are not typically associated with osteoporosis, it may be prudent to
assess bone density in a middle-aged women who presents with radial head fracture.
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5 Epidemiology
One-third of all elbow fractures involve the radial head. The male-female ratio is roughly 1:1, but these
fractures may be slightly more common in women. Men who sustain radial head fractures tend to be
younger than women with the same fracture. That may be because men usually have a high-energy
mechanism of injury such as a fall from height or sports injury, whereas women, who tend to have lowenergy injuries, sustain the fracture due to inherent bone fragility.
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6 Differential diagnosis
Associated injuries, which should be ruled out when a radial head fracture is suspected or confirmed,
include fractures of the capitellum, fractures of the distal radius, dislocation of the distal radio-ulnar
joint (the so-called Essex-Lopresti fracture), rupture of the medial collateral ligament (MCL) causing
valgus instability, rupture of the triceps tendon, and elbow dislocation. Radial head fractures are known
to present in combination with MCL ruptures and coronoid process fractures, a constellation known as
the “terrible triad.”
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7 Red flags
Limited elbow range of motion may be due to a hemarthrosis (which should be aspirated to allow
evaluation of passive range of motion as well as for pain relief), but this limitation could also reflect a
displaced fragment.
As noted above and below, the same mechanism that causes a radial head fracture (a fall on the
outstretched hand, typically) can also cause other injuries at the elbow, including a humeral fracture; a
medial collateral ligament sprain; or even a triceps rupture (akin to a quad tendon rupture). As such, a
radial head fracture seen on radiograph is itself a "red flag" for an associated injury at the elbow and
wrist. Therefore, the clinician must be sure that radiographs visualize both joints.
A fracture from what appears to be a low-energy mechanism in an "at-risk patient" may suggest
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8 Treatment options and outcomes
The goals of treatment are to correct any block to forearm rotation, to restore stability of the elbow and
forearm, and to allow early range of motion.
The Mason classification of radial head fractures is useful for determining treatment options. A Mason
Type 1 fracture is a nondisplaced fracture with no mechanical blockage to forearm rotation. These
fractures can be treated with a sling and early range of motion after 24-72 hours (indeed, as soon after
injury as discomfort subsides). Aspiration of hemarthrosis in the radiocapitellar joint with local injection
of anesthetic can relieve pain and aid in early range of motion. Sometimes a long arm splint for a few
days is helpful for pain relief.
xray of Mason Type 1 radial head fracture
If there is mild displacement, angulation, impaction, or depression of the fracture (but still no
mechanical block to forearm rotation), the fracture is a Type 2. These fractures typically do best if fixed
surgically. The type of internal fixation will vary depending on fracture pattern and extent. Screws may
be sufficient for a partial articular fracture, whereas a plate may be required for fractures that extend
into the radial neck. The optimal fracture for ORIF has 3 or fewer articular fragments.
xray of Mason Type 2 radial head fracture
Fractures with significant displacement, angulation, impaction, or depression or with mechanical
blockage are classified as Type 3. For most of these, radial head excision with prosthetic replacement is
xray of Mason Type 3 radial head fracture
Radial head excision alone, without placement of a prosthetic head, obviates the need to wait for bone
healing, but may lead to symptomatic proximal migration of the radius. The inter-osseous ligament
between the radius and ulna may prevent some migration, but the absent “base” to the radius may
make such migration inevitable.
A Mason Type 4 is a radial head fracture with an elbow dislocation and care is directed first at restoring
the joint: patients with this injury should be sent to the Emergency Ward for urgent care.
Stiffness or contracture may occur secondary to prolonged immobilization of the elbow; therefore, it is
essential to start active range of motion as early as possible. Pain, swelling, and inflammation may be
hindering motion and should be investigated further for unrecognized injury. A supervised therapy
program may maximize outcomes.
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Chronic wrist pain may be the result of an unrecognized injury to the DRUJ, interosseous ligament, or
triangular fibrocartilage complex.
The posterior interosseous nerve (PIN) is vulnerable to injury during operative treatment. PIN
neuropathy is a motor syndrome that results in wrist and finger drop.
Proximal radial migration may occur after radial head excision in the case of unrecognized unstable
fracture-dislocations such as an Essex-Lopresti injury.
Other possible complications include malunion, non-union, avascular necrosis, heterotopic bone
formation, complex regional pain syndrome and posttraumatic radio-capitellar osteoarthritis.
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9 Risk factors and prevention
The link between osteoporosis and radial head fractures is still being investigated. The fact that women
over 50 years old tend to sustain radial head fractures in low-energy falls is suggestive of a correlation
with osteoporosis. If a strong correlation does exist, women over 50 should be offered screening for
osteoporosis to prevent osteoporotic fractures.
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10 Miscellany
In one study by Duckworth et al, a trend was observed toward increased incidence of radial head
fractures in patients with a lower socioeconomic status.
Note that the radial head and neck are located at what a lay person would identify as the “bottom” of
the bone.
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11 Key terms
Radial head fracture, elbow, fracture-dislocation, stability, early range of motion
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12 Skills
Radiocapitellar joint aspiration

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