Distal radial fracturesThe 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.

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

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

Distal radial fracturesExtra-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 ofthe radius and ulna.

AnatomyThe radiocarpal joint is a synovial joint thatconnects the hand to the forearm. The distal radius and ulna articulate at the radioulnar joint. 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 ofa soft-tissue injury.

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

Distal radial fracturesCommon 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.

Distal radial fracturesThe 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 injuryfrom 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.

Distal radial fracturesInjury 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.

Distal radial fracturesIntercarpal 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.The extensor pollicis longus tendon is most frequently ruptured.

DiagnosticsPosteroanterior (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. 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. Shortening of RH may indicate impaction of the radial head when compared with a normal contralateral wrist.

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 15-25. Angulation of the radial head alsoprovides impaction clues

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 10-25. A negative volar tilt indicates dorsal angulation of the distal, radial articular surface.

Bartons fractureJohn Rhea Barton characterized the Barton fracture in 1838. This fracture involves a dorsal rim injury of the distal portion of the radius. Carpal displacement distinguishes this fracture from a Smith's or a Colles' fracture and that the dislocation is the most striking radiographic finding.

2 typesVolar Barton fracture is thought to occur with the same mechanism as the Smith fracture, with more force and loading on the wrist. 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.

Bartons fractureThe Bartonfracture 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

Differential diagnosisColles fracture

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 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.

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

Differential diagnosisSmiths fracture

An impact to the dorsum of the hand or a hyperflexion or hypersupination injury is thought to be the cause. Smiths 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

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

Bartons fracture: radiographsPA and lateral views of the wristinvolve 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 scanscould be used to evaluate articular congruity of the distal radius

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 volar displacement of the scaphoid associated with an intra-articular distal radial fracture.

Bartons fracture: treatmentNon Operative Treatment: - many of these frxs will fail nonoperative treatment; - manipulative reduction is same as for Colles Fracture; - stability of reduction of dorsal Barton frx is best obtained with wrist extension to take advantaage of intact volar carpal ligament; - immobilization for 6 weeks in short arm plaster cast;

Operative Treatment: - is best treated by closed reduction, application of external fixation, followed by percutaneous pin insertion; - if reduction is not anatomic, fraying of the tendon at this level may to late rupture; - tendency to redisplace may require ORIF thru dorsal approach;