Distal radius fracture

- Represents a sixth of all fractures treated in A&E

- Risk factors for fractures of the distal radius in the elderly include decreased bone mineral density, female sex, family history and early menopause.

Anatomy

 - Articular surface has a biconcave surface for articulation with the scaphoid and lunate, as well as a notch for articulation with the distal ulna.

- 80% of axial load is supported by the distal radius and 20% by the ulna and the triangular fibrocartilage complex (TFCC).

- Reversal of the normal palmar tilt results in load transfer onto the ulna and TFCC. The remaining load is then borne by the distal radius and concentrated on the dorsal aspect of the scaphoid fossa.

- Numerous ligamentous attachments exist to the distal radius; often these remain intact during a distal radius fracture, allowing reduction through ligamentotaxis.

- The volar ligaments are stronger and provide more stability to the radiocarpal articulation than the dorsal ligaments.

 Mechanism of injury

 - In younger groups the mechanism often involves falls from a height, road traffic accidents or injuries during sports.

- In the elderly, low-energy falls can result in a fracture.

- The radius initially fails in tension on the volar aspect,with the fracture propagating dorsally, whereas bending moment forces induce compression stresses resulting in dorsal comminution. Cancellous impaction of the metaphysis further comprises dorsal stability. Shearing forces influence the injury pattern often resulting in articular surface involvement.

 Clinical evaluation

 - Patients can present with variable deformity and displacement in relation to the wrist, dorsal in Colles and dorsal Barton fractures and volar in Smith and volar Barton’s fractures.

- Ensure examination of the elbow and shoulder for associated injuries.

- Neurovascular examination should pay particular attention to median nerve function. Carpal tunnel compression symptoms result from traction during forced hyperextension of the wrist, direct trauma from fracture fragments, haematoma formation or increased compartment pressure.

 Radiology

 - PA and lateral views of the wrist should be obtained. Contralateral views can help in assessing normal ulnar variance and scapholunate angle.

- Normal radiographic relationships:

Radial inclination- 13-30 degrees

Radial length- 8-18 mm

Palmar tilt 0-28 degrees.

Radial height is the difference between the distal most point of the radial styloid and the distal most point of the ulnar articular surface.

Radial inclination is the relative angle of the distal radial articular surface to a line perpendicular to the long axis of the radius.

Volar tilt is the angle formed between a line connecting the distal points of the volar and dorsal rim of the radius, and a second line perpendicular to the long axis of the radius. This illustration represents normal values.

Colles fracture

- Demonstrates dorsal angulation, dorsal displacement, radial shift and radial shortening.

- Often described as a dinner fork deformity

- More than 90% of distal radius fractures are of this pattern.

- Mechanism is a fall on a hyper extended , radially deviated wrist with the forearm in pronation

Smith fracture

- A distal radius fracture with volar angulation.

- Mechanism is a fall onto a flexed wrist with the forearm in supination

- Unstable fracture pattern, often requires ORIF.

Barton fracture

- A shearing mechanism results in a fracture-dislocation or subluxation of the wrist in which the dorsal or volar rim.

- Mechanism is fall on a dorsiflexed wrist with the forearm in pronation.

- Majority of these fractures are unstable and require ORIF with a buttress plate.

Radial styloid fracture (chauffeur’s fracture)

- Avulsion fracture with extrinsic ligaments remaining attached to the styloid fragment.

- Mechanism of injury is compression of the scaphoid against the styloid with the wrist in dorsiflexion and ulnar deviation.

- Associated with intercarpal ligamentous injuries i.e scapholunate dissociation, perilunate dislocation).

Treatment

Nonoperative

- All displaced fractures should undergo closed reduction even if further surgical management is expected. This alleviates post injury swelling, gives pain relief and relieves compression of the median nerve.

- Cast immobilisation indicated for non- or minimally displaced fractures, displaced fractures with a stable fracture pattern, low-demand elderly patients in whom future functional impairment is less important than operative risks.

- Haematoma block with IV sedation, Bier block or conscious sedation can be used to provide analgesia for closed reductions.

Technique of closed reduction (dorsally tilted fracture)

- Distal fragment is hyperexended

- Traction is applied to reduce the distal to the proximal fragment with pressure applied to the distal radius.

- Long arm splint is applied, with the wrist in neutral to slight flexion.

- Cast should leave the MCP joints free.

- Cast should be worn for 6 weeks or until radiographic evidence of union.

Operative

Indications:

-High energy injury, secondary loss of reduction, articular comminution, DRUJ incongruity, open fractures.

Techniques

 Percutaneous pinning: primarily used for extra articular fractures or two part intra articular fractures.

 External fixation: use has diminished in popularity since advent of volar locking plate.

 ORIF

- Volar locking plate

 Complications

 Median nerve dysfunction:

 Malunion or nonunion: results from inadequate fracture reduction or stabilization

 Posttraumatic arthritis: which is a consequence of radiocarpal and radioulnar articular injury, emphasising the need  for anatomica reduction.

Epidemiology: Most common upper extremity fracture. Older patients sustaining a fall on outstretched hand with a history of osteopenia. Female-to-male ratio of 4:1.

Anatomy: Articular surface is divided into two hyaline cartilage–covered facets for articulation with the carpal scaphoid and lunate. A well-defi ned ridge traversing from the dorsal to the palmar surface separates the two facets.

Weight-bearing distribution of the wrist is 80% radius and 20% ulna and triangular fibrocartilage complex (TFCC). The articular end of the radius slopes in an ulnar and palmar direction. A reversal of palmar tilt will result in excessive load transfer to the ulna and TFCC, resulting inulnar-sided pain, also known as ulnar abutment syndrome. Numerous ligaments attach the radius to the proximal carpal, thus reduction is achieved with ligamentotaxis. Dorsal stronger than volar. Dorsal comminution is a result of dorsal cortical failure in compression with tension failure of the volar cortex.

Radiographic Parameters: Radial height is 11 to 13 mm. Radial inclination is 22 degrees.

Palmar tilt is 11 degrees.

Distal Radius Fracture: For Frykman classification

Eponyms:

Extra-articular Fractures: (90% of Distal Radius Fractures)

• Colles fracture (dorsal angulation, apex volar). Fall on extended wrist with pronation.

• Smith fracture (volar angulation, apex dorsal). Fall on fl exed wrist with supination.

Intra-articular Fractures:

• Die Punch Fracture: Lunate impaction injury into distal radius.

• Barton’s Fracture: High energy shear forces result in intra-articular fracture; carpal bones move

with sheared radial rim fragment.

• Volar Barton’s: Wrist in fl exion

• Dorsal Barton’s: Wrist in extension

• Chauffeur Fractures/Backfi re Fractures/Hutchinson Fractures: Fractures of the radial styloid.

Treatment:

Nonoperative: Closed Reduction and Casting

• Reduction and splinting in the emergency department followed by casting 3 to 4 days after injury. Repeat radiographs are obtained to ensure accurate reduction.

Operative Treatment:

• External fi xator

• Volar plating/dorsal plating

• Fix distal radioulnar joint (DRUJ) with pinning in supination

Complications:

• Median nerve dysfunction (15% to 25%); usually from hematoma pressure or lidocaine effect from hematoma block

• Reflex sympathetic dystrophy

• Loss of active range of motion

• Tendon rupture: Extensor pollicis longus secondary to mechanical irritation over fracture callus

• DRUJ injuries

• Scaphoid lunate instability; widening greater than 2 mm