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Radius, Distal Fractures
2010-07-19 16:08zhi_yuan2210 发布 浏览 11318 评论 0 发表评论 上一篇 下一篇

 

转载:Author: Browyn Richards, MD, Staff Physician, Department of Family Practice, Boone Branch Medical Clinic, Portsmouth Naval Hospital
Coauthor(s): Ricardo Riego de Dios, MD, Staff Physician, Department of Diagnostic Radiology, Naval Hospital Jacksonville, Naval Air Station; William D Craig, MD, MBA, Chairman and Registrar and GU Section Head, Department of Radiologic Pathology, Armed Forces Institute of Pathology
Contributor Information and Disclosures

Updated: Aug 18, 2009

Introduction

Background

The distal radial fracture is the most common forearm fracture. It is usually caused by a fall onto an outstretched hand (FOOSH). It can also result from direct impact or axial forces. The classification of these fractures is based on distal radial angulation and displacement, intra-articular or extra-articular involvement, and associated anomalies of the ulnar or carpal bones.1,2,3,4

Posteroanterior view of an adult's left wrist dem...

Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.

Posteroanterior view of an adult's left wrist dem...

Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.



Coronal computed tomography (CT) scan demonstrate...

Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.

Coronal computed tomography (CT) scan demonstrate...

Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.



Sagittal computed tomography (CT) scan demonstrat...

Sagittal computed tomography (CT) scan demonstrates a comminuted distal radial fracture with intra-articular involvement.

Sagittal computed tomography (CT) scan demonstrat...

Sagittal computed tomography (CT) scan demonstrates a comminuted distal radial fracture with intra-articular involvement.

Most distal radial fractures are diagnosed by conventional radiography. Computed tomography (CT) scanning and magnetic resonance imaging (MRI) are used to evaluate complex distal radial fractures for the assessment of associated injuries and for surgical planning.


Recent studies

Kirmani et al at the Mayo Clinic noted that distal forearm fractures peak during the adolescent growth spurt but that the structural basis for this is unclear. They concluded, on the basis of their study findings, that regional deficits in cortical bone may underlie the adolescent peak in forearm fractures. From prepuberty to midpuberty, cortical thickness and density decreased in girls but were unchanged in boys, before rising to higher levels at the end of puberty in both girls and boys. During midpuberty to late puberty in both sexes, the proportion of load borne by cortical bone decreased, along with the ratio of cortical to trabecular bone volume. From late puberty onward, trabecular parameters (ie, bone volume fraction, trabecular number, and thickness) remained the same in girls but increased in boys. Total bone strength increased across all age groups for both boys and girls, but boys had greater bone strength than girls after midpuberty.5

Bianchi et al analyzed ultrasound examinations of 9 consecutive patients with a history of distal radius fractures treated by open reduction and internal fixation of the volar plate. They found that ultrasonography is an effective, dynamic, and noninvasive technique with which to diagnose and evaluate damage to the extensor tendons and their synovial sheaths.6

Souer et al evaluated 84 patients after operative fixation of unstable distal radius fractures to identify the most important determinants of physician-based and patient-based scoring systems for the wrist and upper extremity after operative treatment. They used the Mayo Wrist Score, the Gartland and Werley Score, and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. The physician-based scoring systems showed moderate correlation with each other and with DASH scores. At early follow-up, pain dominated the patient's perception of function, as measured by the DASH score and the Gartland and Werley Score. According to the authors, because perception of pain and strength of grip (measured by the Mayo Wrist Score) have been in some cases shown to be influenced by psychosocial factors, measures of wrist function may be vulnerable to illness behavior.1

 

Pathophysiology

Distal radial fractures occur primarily after a fall onto an outstretched hand (FOOSH) mechanism, but subtypes of these fractures occur by other mechanisms.

Frequency

United States

In the United States, 17% of all emergency room visits result from wrist injuries.7,8 McMurtry and colleagues reported that distal radial fractures account for one sixth of all fractures seen in the emergency department.

Mortality/Morbidity

Resnick notes that approximately 40-78% of distal radial fractures are associated with the disruption of the triangular fibrocartilage (TFC) complex.9 Scapholunate and lunotriquetral interosseous ligament injuries occur in 20-50% and 10-15% of cases, respectively.

Common complications of distal radial fractures also include ulnar nerve injury, carpal tunnel syndrome, posttraumatic radiocarpal osteoarthritis with possible limited range of motion, heterotopic ossification, reflex sympathetic dystrophy (RSD), tendon rupture, nonunion, and radial shortening.

The most common complication of associated soft-tissue injury is peripheral nerve dysfunction. The median nerve is most commonly affected, but the ulnar nerve also may be injured. Mechanisms for neuropathy of the median nerve include direct trauma by fracture or displacement, injury through a proximal radial fragment, and injury from displacement of a volar fragment. The ulnar nerve is damaged by medial displacement of the radial fragment or by the ulnar head being volarly displaced.10

Injury to arteries occurs with open and closed fractures. It can also occur with markedly displaced fractures and with dislocations of the radius and ulna. Tendon lacerations occur from high-energy injuries and should be suspected with open fractures and high-velocity injuries. The incidence of tendon rupture is less than 0.2%, and tendon rupture is a late sequela of distal radial fractures.10

Intercarpal injuries may accompany fracture dislocations of the distal forearm. Scaphoid fractures are not uncommon. Intercarpal ligament injuries also may occur. Fractures through the radial styloid can disrupt the radioscapholunate and scapholunate interosseous ligaments, causing a disruption between the 2 bones.10 The extensor pollicis longus tendon is most frequently ruptured.

 

Race

To the authors' knowledge, no racial preferences have been reported.

Sex

Most wrist fractures occur in older postmenopausal women, with a female-to-male ratio of 4:1.11 However, in adolescent boys and girls, the ratio is 3:1, reflecting a differing level of sports involvement between boys and girls.12

Age

A bimodal age distribution has been documented for distal radial fractures; peaks occur at ages 5-14 years and at ages 60-69 years.12

Extra-articular metaphyseal fractures occur in elderly patients because of the thin osteoporotic cortex. Intra-articular fractures with joint surface displacement occur in young patients.

Age influences the location of fractures in the forearm and wrist. Young children present with metaphyseal fractures of the radius and ulna; adolescents, with physeal separations of the radius; and young adults, with scaphoid fractures. Middle-aged and elderly patients present with fractures of only the distal radius or of the radius and ulna.

 

Anatomy

The radiocarpal joint is a synovial joint that connects the hand to the forearm. The distal radius and ulna articulate at the radioulnar joint. The triangular fibrocartilage (TFC) is a concave, elliptical articular disc that extends from the ulnar side of the radius and forms a bridge to the styloid process of the ulna. The TFC is a key stabilizer of the distal radioulnar joint. A central ridge divides the radial articular surface into the scaphoid and lunate facets.

The pronator quadratus muscle is located across the volar aspect of the distal radius and ulna. This muscle is associated with an underlying fat pad that is seen as a flat, lucent line anterior to the distal end of the radius on the lateral image and that, if a bulge is present, is indicative of a soft-tissue injury.

The TFC is best evaluated by using arthrography or MRI.

 

Presentation

Wrist injuries that cause pain, edema, crepitus, deformity, or ecchymosis should be evaluated for radial fractures. Missed distal radial fractures can lead to significant morbidity.

A universal classification of distal radial fractures was proposed in 1990. This system differentiates between extra-articular and intra-articular fractures, as well as between stable and unstable fractures; it was created as a treatment-based algorithm. Classification systems are based on the following 2 principles:

  • The classification should dictate the treatment.
  • The classification should suggest the long-term, functional results of treatment or be correlated with these anticipated results.2,13,14,15,16,17

Table 1. Universal Classification of Distal Radial Fractures

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Table
Classification Description
I Nonarticular, nondisplaced
II
   A
   B
   C
   Nonarticular, displaced
   Reducible, stable
   Reducible, unstable 
   Irreducible
III    Articular, nondisplaced
IV
   A
   B
   C
   D
   Articular, displaced
   Reducible, stable
   Reducible, unstable
   Irreducible
   Complex
Classification Description
I Nonarticular, nondisplaced
II
   A
   B
   C
   Nonarticular, displaced
   Reducible, stable
   Reducible, unstable 
   Irreducible
III    Articular, nondisplaced
IV
   A
   B
   C
   D
   Articular, displaced
   Reducible, stable
   Reducible, unstable
   Irreducible
   Complex


 

Preferred Examination

Posteroanterior (PA), lateral, and oblique radiographs of the injured forearm should be obtained. Oblique views reveal intra-articular involvement that is not apparent on the other views. The semisupinated, oblique view demonstrates the dorsal facet of the lunate fossa, whereas the partially pronated, oblique PA view allows visualization of the radial styloid.

Radial height is assessed on the PA view. It is a measurement between 2 parallel lines that are perpendicular to the long axis of the radius. One line is drawn on the articular surface of the radius, and the other is drawn at the tip of the radial styloid. The normal radial height is 9.9-17.3 mm.18 Measurements of less than 9 mm in adults suggest the presence of comminuted or impacted fractures of the radial head. Comparison with the contralateral normal wrist is recommended if the diagnosis is unclear (see Images 1-2).

Radial height (RH) is measured by drawing 2 paral...

Radial height (RH) is measured by drawing 2 parallel lines perpendicular to the long axis of the radius. Shortening of RH may indicate impaction of the radial head when compared with a normal contralateral wrist. Ulnar variance (UV) is measured here by using the method of perpendiculars, in which 2 lines are drawn perpendicular to the long axis of the radius. One line is drawn on the ulnar-side articular surface of the radius, and the other is drawn on the ulnar carpal surface. This image demonstrates ulnar plus variance.

Radial height (RH) is measured by drawing 2 paral...

Radial height (RH) is measured by drawing 2 parallel lines perpendicular to the long axis of the radius. Shortening of RH may indicate impaction of the radial head when compared with a normal contralateral wrist. Ulnar variance (UV) is measured here by using the method of perpendiculars, in which 2 lines are drawn perpendicular to the long axis of the radius. One line is drawn on the ulnar-side articular surface of the radius, and the other is drawn on the ulnar carpal surface. This image demonstrates ulnar plus variance.



Posteroanterior view of an adult's left wrist dem...

Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.

Posteroanterior view of an adult's left wrist dem...

Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.



The radial inclination is measured by drawing a l...

The radial inclination is measured by drawing a line perpendicular to the long axis of the radius and a tangential line from the radial styloid to the ulnar corner of the lunate fossa.

The radial inclination is measured by drawing a l...

The radial inclination is measured by drawing a line perpendicular to the long axis of the radius and a tangential line from the radial styloid to the ulnar corner of the lunate fossa.



The volar tilt, or palmar inclination, is an angl...

The volar tilt, or palmar inclination, is an angle between a line drawn perpendicular to the long axis of the radius and a tangential line drawn along the radial articular surface.

The volar tilt, or palmar inclination, is an angl...

The volar tilt, or palmar inclination, is an angle between a line drawn perpendicular to the long axis of the radius and a tangential line drawn along the radial articular surface.



 

Radial inclination is measured on the PA view; this is a measurement of the radial angle. A line is drawn along the articular surface of the radius perpendicular to the long axis of the radius, and a tangent is drawn from the radial styloid. The normal angle is 15-25º.19,8 Angulation of the radial head also provides impaction clues (see Image 3).

The volar tilt, or palmar inclination, is measured on the lateral view. A line perpendicular to the long axis of the radius is drawn, and a tangent line is drawn along the slope of the dorsal-to-palmar surface of the radius. The normal angle is 10-25º.19,8 A negative volar tilt indicates dorsal angulation of the distal, radial articular surface (see Image 4).7

Ulnar variance is measured on PA radiographs. In adults, the following 3 methods are used18 :

  • Project-a-line technique
  • Method of perpendiculars
  • Concentric-circle technique

Ulnar variance is described as being zero, minus, or plus. Positive (plus) or negative (minus) ulnar variance should be compared with the variance on the contralateral normal forearm.19 Normal ulnar variance is 9-12 mm. Note that ulnar variance does not depend on the length of the ulnar styloid but on the positioning of the forearm, as well as on the radiographic technique (see Image 1).

Because the distal radius and ulna can fracture and because related ligamentous or bony injuries can be occult, an evaluation of the soft tissues of the distal forearm is important. For this assessment, 2 fat planes on the lateral view and 5 fat planes on the PA view are useful.

On the lateral view, the deep fat pad of the pronator quadratus and the dorsal skin subcutaneous fat line can be seen anterior to the distal radius. The deep fat pad of the pronator quadratus forms a slight, ventral concave line. This is convexly bowed in a ventral direction or completely absent in pathologic conditions. The dorsal skin subcutaneous fat line is flat or is a dorsal concave line. It is abnormal when it is convex in the dorsal direction.

The PA view shows the thenar, hypothenar, pararadial, and paraulnar skin subcutaneous fat lines and the deep, navicular fat pad. Swelling that is not associated with an observed fracture should initiate a search for an additional abnormality.

In suspected instances of extensive soft-tissue damage, CT scanning or MRI may be used.

 

Limitations of Techniques

Plain radiographs do not show the extent of soft-tissue damage or of radioulnar and radiocarpal joint involvement.

Radiography

Findings

Colles fracture

In 1813, Abraham Colles described the Colles fracture, which is reported to be the most common distal radial fracture. The injury is usually produced by a fall onto an outstretched hand (FOOSH) mechanism with the wrist in dorsiflexion. The impact produces a transverse fracture in the distal 2-3 cm of the radial articular surface. The fracture is dorsally displaced and may be comminuted. The fracture pattern is often described as a silver or dinner-fork deformity. The fracture fragments are usually impacted and comminuted along the dorsal aspect; the fracture can extend into the epiphysis to involve the distal radiocarpal joint or the distal radioulnar joint.

Resnick noted that 50-60% of Colles fracture cases are associated with an ulnar styloid fracture.9 An associated ulnar styloid fracture should prompt an investigation for tears of the TFC. The TFC extends from the rim of the sigmoid notch of the radius to the ulnar styloid and is thought to stabilize the distal radioulnar joint (see Image 4, Image 8).

Lateral view of the wrist demonstrates a Colles f...

Lateral view of the wrist demonstrates a Colles fracture (in which there is a dorsal angulation of the fracture fragment).

Lateral view of the wrist demonstrates a Colles f...

Lateral view of the wrist demonstrates a Colles fracture (in which there is a dorsal angulation of the fracture fragment).



PA and lateral views involve a minimal examination. The examiner should note the direction of displacement and angulation, the degree of comminution, the intra-articular involvement, and the radial length or variance in comparison with the normal side. The ulnar inclination is approximately 14° on the PA view, and the volar tilt is approximately 12° on the lateral view.

 

Two classification systems are used: the Association for Osteosynthesis (AO) system and the Frykman system.

Table 2. AO Classification of Colles Fractures

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Table
Type Description
A Extra-articular
B Partial articular

C
   1
   2
   3
Complete articular
   Simple articular and metaphyseal fracture
   Simple articular with complex metaphyseal fracture
   Complex articular and metaphyseal fracture
Type Description
A Extra-articular
B Partial articular

C
   1
   2
   3
Complete articular
   Simple articular and metaphyseal fracture
   Simple articular with complex metaphyseal fracture
   Complex articular and metaphyseal fracture

Table 3. Frykman Classification of Colles Fractures

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Table
Type Radius Ulna Radiocarpal Radioulnar
I Extra-articular Absent Absent Absent
II Extra-articular Present Absent Absent
III Intra-articular Absent Present Absent
IV Intra-articular Present Present Absent
V Intra-articular Absent Absent Present
VI Intra-articular Present Absent Present
VII Intra-articular Absent Present Present
VIII Intra-articular Present Present Present
Type Radius Ulna Radiocarpal Radioulnar
I Extra-articular Absent Absent Absent
II Extra-articular Present Absent Absent
III Intra-articular Absent Present Absent
IV Intra-articular Present Present Absent
V Intra-articular Absent Absent Present
VI Intra-articular Present Absent Present
VII Intra-articular Absent Present Present
VIII Intra-articular Present Present Present

The AO and Frykman classifications are useful in discussing prognosis.

Complications of the Colles fracture include compressive neuropathy, posttraumatic arthrosis, Volkmann ischemic contracture, acute carpal tunnel syndrome, and shoulder-hand syndrome.8

Colles fractures occur more frequently in elderly persons, as a result of osteoporosis.7,20

Smith fracture

Robert Smith described the Smith fracture in 1847. An impact to the dorsum of the hand or a hyperflexion or hypersupination injury is thought to be the cause. A Smith fracture is usually called a reverse Colles fracture because the distal fragment is displaced volarly. It is often described as a garden-spade deformity. The ulnar head can be displaced dorsally (see Images 5-6).

Smith fracture (in which there is a volar displac...

Smith fracture (in which there is a volar displacement of the distal fracture fragment).

Smith fracture (in which there is a volar displac...

Smith fracture (in which there is a volar displacement of the distal fracture fragment).



 

Anteroposterior (AP) and lateral views of the wrist involve a minimal examination. The criteria that are used to evaluate Colles fractures also apply to Smith fractures.

Table 4. Thomas Classification of Smith Fractures

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Table
Type Description
I Most stable, extra-articular, transverse distal radial fracture with palmar and proximal displacement
II Barton type, palmar-lip fracture of the distal radius with dislocation of the carpus
III Unstable, oblique, juxta-articular fracture of the distal radius and tilted palmar
Type Description
I Most stable, extra-articular, transverse distal radial fracture with palmar and proximal displacement
II Barton type, palmar-lip fracture of the distal radius with dislocation of the carpus
III Unstable, oblique, juxta-articular fracture of the distal radius and tilted palmar

The complications of Smith fractures are similar to those of Colles fractures.

Barton fracture

John Rhea Barton characterized the Barton fracture in 1838.8 This fracture involves a dorsal rim injury of the distal portion of the radius. The volar Barton fracture is thought to occur with the same mechanism as the Smith fracture, with more force and loading on the wrist. The dorsal Barton fracture is caused by a fall on an extended and pronated wrist, increasing carpal compression force on the dorsal rim. The salient feature is a subluxation of the wrist in this die-punch injury.

The Barton fracture involves either the palmar or dorsal radial rim, and the mechanism is intra-articular. By definition, this fracture has some degree of carpal displacement, which distinguishes it from a Colles or Smith fracture. The palmar variety is more common than the dorsal type (see Images 7-8).8

Posteroanterior radiograph of a Barton fracture. ...

Posteroanterior radiograph of a Barton fracture. Note the intra-articular fracture of the radius with the widening of the space between the scaphoid and lunate structures.

Posteroanterior radiograph of a Barton fracture. ...

Posteroanterior radiograph of a Barton fracture. Note the intra-articular fracture of the radius with the widening of the space between the scaphoid and lunate structures.



Lateral radiograph of a Barton fracture. Note the...

Lateral radiograph of a Barton fracture. Note the volar displacement of the scaphoid associated with an intra-articular distal radial fracture.

Lateral radiograph of a Barton fracture. Note the...

Lateral radiograph of a Barton fracture. Note the volar displacement of the scaphoid associated with an intra-articular distal radial fracture.



 

PA and lateral views of the wrist involve a minimal examination, but a true lateral projection is needed to evaluate the degree of carpal subluxation. In 1992, Wood and Berquist suggested that trispiral tomograms or coronal and/or sagittal CT scans could be used to evaluate articular congruity of the distal radius.8

Barton fractures are classified as dorsal or palmar (always intra-articular), and they always involve carpal subluxation.

Complications of Barton fractures are similar to those of Colles fractures.

Hutchinson, chauffeur's, or radial styloid fracture

The chauffeur's fracture derives its name from injuries that were acquired, in the days when motor vehicles were cranked, when a vehicle backfired. The force is described as a direct axial compression of the scaphoid into the radial facet. The radial styloid is fractured, with associated avulsion of the radial collateral ligament.9,8  A chauffeur's fracture represents an avulsion related to the attachment sites of the radiocarpal ligaments or of the radial collateral ligament. Scapholunate dissociation and lesser arc injuries of the wrist may be indicated by a fracture line on the radial articular surface between the scaphoid and lunate fossae.

The PA view usually demonstrates the lesion. Wood and Berquist report that little or no abnormality is seen on lateral views.8

Chauffeur's fractures are classified as simple or comminuted radial styloid fractures and as displaced or nondisplaced fractures. These injuries show no evidence of carpal subluxation.

Complications include scapholunate dislocation, osteoarthritis, and ligamentous damage.

Galeazzi, or Piedmont, fracture

A Galeazzi fracture results from a FOOSH mechanism with the forearm hyperpronated or from a direct impact to the dorsal radial wrist. The radial diaphysis at the distal and middle third junction is fractured, with associated subluxation of the distal radioulnar joint. On PA views, the radius is shortened and the radioulnar joint is disrupted.

Radioulnar distances greater than 2 mm are suggestive of a ligamentous injury and/or a tear of the TFC. On the lateral view, the distal radius is angulated either volarly or radially as a result of the pull of the brachioradialis muscle with more than 3 mm of ulnar displacement.21,8 An associated ulnar styloid fracture also may be present.

PA views may show a displaced radial and ulnar styloid. The lateral view may reveal the associated radioulnar dislocation that is occult on the AP view.

Classification is based on the direction of displacement of the distal fracture fragment.

Complications include radial malunion, nonunion, and persistent subluxation of the radioulnar joint.8

Essex-Lopresti fracture

The Essex-Lopresti fracture consists of a comminuted and displaced radial head fracture along with disruption of the distal radioulnar joint and interosseous membrane. The thickened ridge of the scaphoid and lunate facets dissipates the energy delivered to the wrist in a FOOSH injury and is thought to account for fractures that occur between the scaphoid and lunate facets of the radius. The fracture line originates at the junction of the scaphoid and lunate fossae on the radial articular surface and courses laterally in a transverse or oblique direction. The intra-articular distal radial fracture of the radial styloid is associated with an avulsion of the radial collateral ligament.

Routine PA and true lateral views are obtained. On the PA view, overlap, widening, or incongruity of the radioulnar joint should be noted. Resnick notes that careful radiographic positioning and measurements are essential, as is transaxial CT scanning or MRI, to assess the extent of displacement or subluxation of the radioulnar joint.9

Complications are similar to those of a Colles fractures and include radioulnar joint instability and TFC damage.

Pediatric distal radial fracture

The distal one third of the forearm is the most common fracture site in children. Dicke notes that these make up 35.8-45% of all pediatric fractures. The primary mechanism of injury is a FOOSH mechanism. Unlike such falls in adults, these falls rarely lead to intra-articular fractures in children, but fractures can occur at the diaphyseal-metaphyseal junction or at the physis. Boys have a higher frequency of distal radial fractures than do girls.

Five classifications of pediatric fractures are used, as follows12 :

  • Plastic deformation - This occurs most commonly in the ulna and fibula.
  • Buckle (torus) fracture - In this, the diaphysis (cortical bone) causes the metaphysis to buckle under compressive forces.
  • Greenstick fracture - This fracture occurs when the tension side of the bone fails as it is bent.
  • Complete fracture - A complete fracture propagates through the entire bone and can occur as a spiral fracture, an oblique fracture, or a transverse fracture.
  • Epiphyseal fracture - This fracture involves the growth plate and/or physis. The distal radial physis is the most frequently injured physis.

Fractures involving the physis are categorized as follows, using the Salter-Harris (SH) classification:

  • Type I - A fracture through only the physis
  • Type II - A fracture occurring through the physis and obliquely through the metaphysis
  • Type III - A fracture occurring through a portion of the physis and longitudinally through the epiphysis
  • Type IV - An oblique fracture extending through the metaphysis, physis, and epiphysis

A displaced pronator fat sign may be the only indication of a nondisplaced Salter-Harris type I fracture. Salter-Harris type II fractures are the most common, according to Waters,22  making up 58% of the fractures considered in a 1993 study by Dicke.

Complications of pediatric distal radius and ulnar fractures include nonunion or malunion, growth-plate arrest that leads to deformity, nerve and vessel damage, sympathetic dystrophy, overgrowth of the healing bone, and, in rare instances, compartment syndrome.

 

Computed Tomography

Axial computed tomography (CT) scan demonstrates ...

Axial computed tomography (CT) scan demonstrates a comminuted distal radial fracture.

Axial computed tomography (CT) scan demonstrates ...

Axial computed tomography (CT) scan demonstrates a comminuted distal radial fracture.



Coronal computed tomography (CT) scan demonstrate...

Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.

Coronal computed tomography (CT) scan demonstrate...

Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.



Sagittal computed tomography (CT) scan demonstrat...

Sagittal computed tomography (CT) scan demonstrates a comminuted distal radial fracture with intra-articular involvement.

Sagittal computed tomography (CT) scan demonstrat...

Sagittal computed tomography (CT) scan demonstrates a comminuted distal radial fracture with intra-articular involvement.


 

Findings

CT scanning is used to plan operative repair or to resolve uncertain findings on conventional radiographs. Optimal results are obtained when sagittal and coronal 2-mm sections are used.

CT scanning may be useful in circumstances involving complex or occult fractures, an evaluation of the distal radioulnar joint and distal radial articular surface, an assessment of fracture healing, or a postsurgical evaluation.

 

Degree of Confidence

CT scanning improves the accuracy of fracture alignment measurements.

Magnetic Resonance Imaging

Findings

MRI is not routinely used in the initial evaluation of acute distal radial fractures or of associated carpal injuries. However, the modality is useful in the assessment of bony, ligamentous, and soft-tissue abnormalities associated with distal radial fractures.

MRI is routinely used to evaluate the integrity of the intercarpal ligaments, the TFC, and the median nerve within the carpal tunnel. Compared with plain radiographs and scintigrams, MRI scans may be more sensitive in detecting early osteonecrosis associated with an evaluation of occult fractures and posttraumatic or avascular necrosis of the carpus.

 

Degree of Confidence

The improved contrast resolution afforded by MRI improves the detection of marrow edema at the site of fracture, which is not radiographically detectable on CT scans.

Wood and Berquist quote a sensitivity of 100% and a specificity of 92% for MRI in the detection of TFC tears, compared with a sensitivity and specificity of 89% and 90%, respectively, for arthrography.8

 

Ultrasonography

Findings

Ultrasonography may be used in pediatric patients to visualize the physes of children in whom mineralization of secondary growth plates has yet to occur. Ultrasonography may also be used in patients who lack bony landmarks. On ultrasonograms, cortical surfaces are echogenic or echoreflective, whereas cartilage or unossified physes are sonolucent or hypoechoic.23

Nuclear Imaging

Findings

Nuclear scintigraphy can be used to detect fractures because the early osteoblastic reaction at fracture margins results in a focal linear accumulation of technetium-99m (99m Tc) methylene diphosphonate (MDP) at the site. However, reports describe poor accumulation of the radiotracer in patients with congestive heart failure or chronic renal failure and in the elderly.23

If a patient is symptomatic or if bony, cartilaginous, or ligamentous abnormalities are suspected despite normal radiographs, radionuclide bone imaging may be helpful. An occult fracture or other physiologically active osteochondral pathology must be excluded when an area of intense focal tracer accumulation is noted. Mildly increased focal tracer uptake suggests ligamentous or cartilaginous pathology. Lack of focal tracer accumulation on delayed images excludes osteochondral involvement.

Radionuclide bone imaging may be helpful in determining a fracture's age and for documenting fracture healing when radiographic results are inconclusive. It is also important in the diagnosis of RSD.

 

Degree of Confidence

Bone scintiscan findings may remain positive for as long as 2 years as a result of vascular recruitment from trauma.23

Metz and Gilula quote a sensitivity and specificity of 96% and 97%, respectively, in the diagnosis of RSD by using radionuclide bone imaging.24

 

Angiography

Findings

Angiography is indicated in cases involving a compromise of vascular structures, as reflected in the clinical presentation.

Intervention

Medicolegal Pitfalls

  • Distal radial fractures that are not appropriately diagnosed with radiographic methods may result in increased morbidity.
    • At minimum, PA and lateral plain radiographs are required, but oblique and other views may be warranted, depending on the patient's history and examination findings.
    • CT scanning and MRI can be used to assess occult fractures and the extent of associated soft-tissue damage.
    • Beware of missed radioulnar subluxations.
  • Some normal wrist variants may simulate fractures of the distal radius.
    • In 1996, Keats described the ulnar styloid ossicle, epiphysis clefts, epiphyseal spurs, remnants of the epiphyseal line, and physiologic ulnar plus variants.25
    • A cleft distal epiphysis may appear as a fracture on an oblique view. An epiphysis or apophysis may develop from many centers. A closed epiphyseal spur may be mistaken for an avulsion. An epiphyseal line remnant may simulate a fracture. A long ulna (ulnar plus variant) may be mistaken for a distal radioulnar joint dislocation.
  • Radiographic findings that are minute or possibly normal variants require comparison with the contralateral normal wrist and further studies before interventional procedures are recommended.

Multimedia

Radial height (RH) is measured by drawing 2 paral... Media file 1: Radial height (RH) is measured by drawing 2 parallel lines perpendicular to the long axis of the radius. Shortening of RH may indicate impaction of the radial head when compared with a normal contralateral wrist. Ulnar variance (UV) is measured here by using the method of perpendiculars, in which 2 lines are drawn perpendicular to the long axis of the radius. One line is drawn on the ulnar-side articular surface of the radius, and the other is drawn on the ulnar carpal surface. This image demonstrates ulnar plus variance.
Radial height (RH) is measured by drawing 2 paral...

Radial height (RH) is measured by drawing 2 parallel lines perpendicular to the long axis of the radius. Shortening of RH may indicate impaction of the radial head when compared with a normal contralateral wrist. Ulnar variance (UV) is measured here by using the method of perpendiculars, in which 2 lines are drawn perpendicular to the long axis of the radius. One line is drawn on the ulnar-side articular surface of the radius, and the other is drawn on the ulnar carpal surface. This image demonstrates ulnar plus variance.

Posteroanterior view of an adult's left wrist dem... Media file 2: Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.
Posteroanterior view of an adult's left wrist dem...

Posteroanterior view of an adult's left wrist demonstrates an impacted distal radial fracture. Measurement of radial shortening and comparison with the contralateral normal wrist aids in the diagnosis.

The radial inclination is measured by drawing a l... Media file 3: The radial inclination is measured by drawing a line perpendicular to the long axis of the radius and a tangential line from the radial styloid to the ulnar corner of the lunate fossa.
The radial inclination is measured by drawing a l...

The radial inclination is measured by drawing a line perpendicular to the long axis of the radius and a tangential line from the radial styloid to the ulnar corner of the lunate fossa.

The volar tilt, or palmar inclination, is an angl... Media file 4: The volar tilt, or palmar inclination, is an angle between a line drawn perpendicular to the long axis of the radius and a tangential line drawn along the radial articular surface.
The volar tilt, or palmar inclination, is an angl...

The volar tilt, or palmar inclination, is an angle between a line drawn perpendicular to the long axis of the radius and a tangential line drawn along the radial articular surface.

Lateral view of the wrist demonstrates a Colles f... Media file 5: Lateral view of the wrist demonstrates a Colles fracture (in which there is a dorsal angulation of the fracture fragment).
Lateral view of the wrist demonstrates a Colles f...

Lateral view of the wrist demonstrates a Colles fracture (in which there is a dorsal angulation of the fracture fragment).

Smith fracture (in which there is a volar displac... Media file 6: Smith fracture (in which there is a volar displacement of the distal fracture fragment).
Smith fracture (in which there is a volar displac...

Smith fracture (in which there is a volar displacement of the distal fracture fragment).

Illustration of the Thomas classification of Smit... Media file 7: Illustration of the Thomas classification of Smith fractures.
Illustration of the Thomas classification of Smit...

Illustration of the Thomas classification of Smith fractures.

Posteroanterior radiograph of a Barton fracture. ... Media file 8: Posteroanterior radiograph of a Barton fracture. Note the intra-articular fracture of the radius with the widening of the space between the scaphoid and lunate structures.
Posteroanterior radiograph of a Barton fracture. ...

Posteroanterior radiograph of a Barton fracture. Note the intra-articular fracture of the radius with the widening of the space between the scaphoid and lunate structures.

Lateral radiograph of a Barton fracture. Note the... Media file 9: Lateral radiograph of a Barton fracture. Note the volar displacement of the scaphoid associated with an intra-articular distal radial fracture.
Lateral radiograph of a Barton fracture. Note the...

Lateral radiograph of a Barton fracture. Note the volar displacement of the scaphoid associated with an intra-articular distal radial fracture.

Posteroanterior view of the left wrist demonstrat... Media file 10: Posteroanterior view of the left wrist demonstrates buckle fractures of the distal radius and ulna.
Posteroanterior view of the left wrist demonstrat...

Posteroanterior view of the left wrist demonstrates buckle fractures of the distal radius and ulna.

Axial computed tomography (CT) scan demonstrates ... Media file 11: Axial computed tomography (CT) scan demonstrates a comminuted distal radial fracture.
Axial computed tomography (CT) scan demonstrates ...

Axial computed tomography (CT) scan demonstrates a comminuted distal radial fracture.

Coronal computed tomography (CT) scan demonstrate... Media file 12: Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.
Coronal computed tomography (CT) scan demonstrate...

Coronal computed tomography (CT) scan demonstrates intra-articular involvement in a distal radial fracture.

Sagittal computed tomography (CT) scan demonstrat... Media file 13: Sagittal computed tomography (CT) scan demonstrates a comminuted distal radial fracture with intra-articular involvement.


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