1.1 Epidemiology

Distal radial fractures are the most common fractures of the upper extremity and account for more than one sixth of all fractures treated in the emergency department. The highest occurrence is in the pediatric (25% of all fractures) and elderly population (18% of all fractures) but DRFs also have a significant impact on the health of young adults.

1.2 Special characteristics

The DRF represents a great therapeutic challenge due to the variety of anatomical patterns, the complexity of intraarticular disruption, and associated soft-tissue and bony injuries.

While most DRFs, especially dorsally displaced and dorsally angulated extraarticular fractures in the elderly can be adequately treated nonoperatively [1], approximately 30% are more complex and require surgical treatment.

2.1 Case history and physical examination

Most DRFs are produced by hyperextension forces. With a low-energy fall, bending forces lead to dorsally displaced extraarticular or intraarticular fractures. Shear forces lead to partial displacement of the palmar joint surface and produce unstable injuries. Compression forces are predominant in high-energy, axial loading injuries and lead to impaction of articular fragments. Avulsion is another high-energy mechanism in fracture dislocations and the avulsed fragments often represent the bony attachments of a ligament [2].

All wrist fractures must be assessed for open wounds (usually on the palmar/ulnar side) and injury to the median or ulnar nerve. Compartment syndrome may develop in high-energy injuries.

2.2 Imaging

2.2.1 Plain x-rays

Plain AP and lateral x-rays must be taken for all DRFs. Oblique views and comparative views of the other wrist can be helpful. X-rays in high-energy trauma should include the entire forearm and wrist.

Normal radiological parameters should be used to assess radiographic anatomy.

AP view (Fig 6.3.3-1)

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  Radial height (length) is the distance between two parallel lines drawn perpendicular to the long axis of radial shaft: one from the tip of the radial styloid and the other from the ulnar corner of the lunate fossa. Average = 12 mm.

  
  
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  Radial inclination is the angle between two lines—one drawn perpendicular to the long axis of the radius at the ulnar corner of the lunate fossa and the other between that point in the lunate fossa and the tip of the radial styloid. Average = 23°.

  
  
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  Ulnar variance is defined as the difference in axial length between the ulnar corner of the sigmoid notch of the radius and the most distal extent of the ulnar head on the PA view. Sixty percent of the population is ulnar neutral.

Lateral view (Fig 6.3.3-2)

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  Palmar inclination is the angle subtended by the line perpendicular to the long axis of the radius and a second line drawn from the dorsal lip to palmar lip of distal radius. Average = 12°.

  
  
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  Teardrop angle is the angle between the line along the central axis of teardrop (U-shaped structure which projects 3 mm palmar from radial diaphysis) and a line of the longitudinal radial axis. The x-ray is 10° tilted. Average = 70°.

The radiographic parameters vary depending on the rotation of the forearm.

The x-rays should be assessed for instability criteria [3]:

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  Significant metaphyseal fragmentation

  
  
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  Angular deformity > 10°

  
  
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  Shortening > 5 mm

  
  
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  Articular displacement > 2 mm

  
  
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  Carpal malalignment

Most of the information required for planning treatment can be obtained from plain x-rays. However, computed tomographic (CT) scan is helpful in complex cases.

2.2.2 Computed tomography

A CT scan should be performed when plain x-rays do not explain the congruity and displacement of the articular surface in the sigmoid notch, lunate facet, and the scaphoid fossa ( Fig 6.3.3-3 ). The sigmoid notch is especially well visualized by CT scan.

Sagittal and coronal reformats and 3-D reconstruction CT provides accurate information about the fracture fragment position, their size, and extension into the metaphyseal bone ( Fig 6.3.3-4 ).

2.2.3 Imaging of associated injuries

About 30–40% of DRFs are associated with additional soft-tissue injuries which may or may not be clinically significant.

Most displaced DRFs are associated with triangular fibrocartilage complex (TFCC) injuries. Intrinsic carpal ligament injuries, particularly the scapholunate, can be seen in extraarticular fractures but are more common with intraarticular fractures, particularly those that separate the scaphoid and lunate fossa. The x-rays should be carefully reviewed for widening of the scapholunate interval ( Fig 6.3.3-5 ) and evidence of carpal instability with scaphoid flexion and lunate extension.

High-energy DRFs may also have associated fractures of the scaphoid waist.

4.1 AO/OTA Fracture and Dislocation Classification

The AO/OTA Fracture and Dislocation Classification is the most detailed classification for the distal radius. Three basic fracture types: extraarticular, partial articular, and complete articular are organized in order of increasing severity according to fracture complexity, treatment challenges, and final patient outcome ( Fig 6.3.3-7 ).

4.2 Fernandez classification

Fernandez [2] taught that a better understanding of the mechanism of injury can provide a better overall assessment of the injury, potential soft-tissue damage and a better algorithm for treatment modalities. It might provide better prognostic information because the complexity of the bone and soft-tissue lesions increases consistently from type I through type V fractures ( Table 6.3.3-1 ). Unfortunately, all contemporary classification systems lack intra-rater and interrater reliability.

Table 6.3.3-1 The Fernandez classification.

Type I Bending fracture of the metaphysis
Type II Shearing fracture of the joint surface
Type III Compression fracture of the joint surface
Type IV Avulsion fractures, radiocarpal fracture, dislocation
Type V Combined fractures (I, II, III, IV); high-velocity injury

6.1 Timing of surgery

The timing of surgery depends upon the associated soft-tissue injuries and the type of definitive surgical fixation and resources.

Complex DRFs have significant soft-tissue injury even if not open. High-energy DRFs should be observed for compartment syndrome and if present an immediate fasciotomy is performed. Gustilo grades 2 and 3 open fractures and fractures with neurovascular injury require prompt surgical management. In most severe soft-tissue problems, a joint bridging external fixator is adequate for the first stage of bony stabilization after debridement.

In most DRFs where surgery is indicated, a closed reduction and plaster (splint) immobilization is recommended until the patient undergoes surgery. Evidence is inconclusive regarding median nerve decompression when nerve dysfunction persists after fracture reduction [5].

6.2 Implant selection

There are many different surgical approaches for DRF treatment. Implants include K-wires and/or external fixators, palmar and/or dorsal plates, intramedullary nails and bridging plates.

6.3 Operating room set-up

A tourniquet is placed and a large drape is spread over the patient′s body, with the free edge wrapped around the injured limb to seal off the arm. The image intensifier is draped except for the image intensifier end (x-ray tube) that will go underneath the hand table and does not need to be covered ( Fig 6.3.3-8 ).

The surgeon sits next to the patient′s head and the assistant on the opposite side of the hand table. The operating room personnel are positioned next to the assistant. Make sure the assistant and the scrub nurse do not impede the access of the image intensifier. The image intensifier display screen is placed in full view of the surgical team and the radiographer ( Fig 6.3.3-9 ).