Wrist fractures

Notes

Introduction

Fractures of the distal radius are common orthopaedic injuries.

They exhibit a bimodal distribution; they are seen in the young following high-energy injuries and as fragility fractures in the elderly.

Treatment aims to optimise functional recovery and may be conservative with cast immobilisation or involve surgical fixation.

Anatomy

The wrist is a synovial joint formed by the distal radius, articular disc and proximal carpal bones.

The radiocarpal (wrist) joint is a synovial joint formed by the distal articular surface of the radius and the articular disc with the scaphoid, lunate and triquetrum. It is a biaxial and ellipsoid joint. The ulna does not form part of the radiocarpal joint.

Whilst held in a neutral position only the scaphoid and lunate are in contact with the radius and articular disc. When the wrist is held in adduction the triquetrum comes into contact with the articular disc.

Radiocarpal joint

Radial inclination

Radial inclination, measured in the AP view, represents the angle between a line perpendicular to the long axis of the radius at the corner of the lunate fossa and a line running from the corner of the lunate fossa to the tip of the radial styloid. The average is around 22 degrees.

Radial inclination

Volar tilt

The articular surface exhibits a ‘volar tilt’ of approximately 11 degrees. Measured in the lateral view it represents the angle between a line perpendicular to the long axis of the radius and a line along the articular surface.

Volar tilt

Ulnar variance

Ulnar variance, measured in the AP view refers to the distance between two lines drawn perpendicular to the long axis of the radius at the level of distal ulnar articular surface and the sigmoid notch of the radius. Normally it is between +2mm to -2mm of neutral.

Ulnar variance

Fracture patterns

Fractures may be described based upon region, displacement, comminution and angulation.

Colles' and Smith's are frequently discussed fracture patterns when taught as students. You will find however in practice, at trauma meetings these eponyms are rarely used - instead replaced with a clear verbal description of the radiological appearances of the fracture. It remains important however to be aware of these eponyms and their meanings.

Colles’ fracture

A type of distal radius fracture defined as an extra-articular fracture of the metaphyseal region of the radius with dorsal angulation (of the distal fragment) and impaction. 

Wrist fracture

Smith’s fracture

Often described as a reverse Colles’. Refers to a fracture of the distal radius with volar angulation of the distal fragment. Tend to be inherently less stable than fractures with dorsal angulation.

Barton fracture

Barton fracture describes an intra-articular fracture of the distal radius. Intra-articular involvement increases risk of arthritis and reduced function. They may have dorsal angulation or volar angulation (volar Barton).

Aetiology

Distal radius fractures most commonly result from a fall onto an outstretched hand (FOOSH).

Fractures of the distal radius may be broadly categorised as high-energy fractures (typically young patients, e.g fall from bike or motorcycle) and fragility fractures (typically elderly, fall from standing height).

Colles’ fracture tend to occur with a fall onto a extended wrist. Smith’s fractures tend to occur with a fall onto a flexed wrist.

Note: In a cohort of patients the fracture will be a symptom of an underlying condition, particularly in the elderly. Always ask yourself why the patient fell! In those whose histories do not support a mechanical fall consider cardiac and neurological causes of falls, loss of consciousness or imbalance.

Clinical features

Fractures of the distal radius are acute injuries, patients will present with pain, swelling and reduced function of the affected joint.

Symptoms

  • Pain
  • Reduced range of movement

Signs

  • Boney tenderness
  • Swelling
  • Deformity

All patients should have a full assessment (and documentation) of the limbs neurovascular status. Complete a full-body assessment for associated injuries.

Investigations & diagnosis

The diagnosis of a wrist fracture may be made clinically and confirmed by a wrist radiograph.

Bedside

  • Observations
  • Urine dip
  • ECG

Bloods

  • FBC
  • U&Es
  • CRP
  • Bone profile
  • Vitamin D
  • Group & save 
  • Clotting screen

Imaging

  • Wrist X-ray: AP and lateral films.
  • CT: allows accurate delineation of the extent of the fracture and any intra-articular involvement.
  • MRI: allows assessment of soft tissue injuries.

Management

The goal of treatment is to restore normal anatomical alignment to encourage healing and preserve functionality.

Management of distal radius fractures is complicated and depends on a myriad of factors. Surgical fixation is reserved for patients who are likely to have poor functional outcomes from closed reduction and cast immobilisation alone - and in whom surgery would improve outcomes.

These include fractures that are intra-articular (and displaced), significantly comminuted or show significant radial shortening. Fractures that are unstable in cast with progressive dorsal angulation and loss of radial height should also be considered for operative intervention. Operative options include ORIF (normally volar approach with volar plate), external fixation and percutaneous K-wires.

Below represents a general framework (though a simplified one) on the management of these fractures. They are in part based upon BOAST The Management of Distal Radial Fractures 2017 and BSSH Best Practice for Management of Distal Radial Fractures 2018.

Initial management

The majority patients presenting with fractures of the distal radius receive their initial management in ED. For those with extra-articular fractures most will attempt a closed reduction and cast immobilisation with appropriate analgesia (e.g. haematoma block and gas & air).

The aim is to restore normal anatomical alignment of the distal radius. Patients are then referred to orthopaedics (or plastic surgery) for review and decision on definitive management.

Dorsal angulation

Under 65

The fracture, patient wishes and co-morbidities will be considered. Review should include examination of the ulnar variance, dorsal tilt and intra-articular step (if present). 

Surgery will typically be considered. If closed reduction is possible then K-wire fixation if generally preferred to ORIF (open reduction and internal fixation).

Over 65

In more elderly patients non-operative management will be likely considered as definitive management. Where there is instability, significant deformity or neurological compromise surgery will be considered.

Volar angulation

Volar angulated fractures are inherently unstable. As a general rule these are managed with open reduction and plate fixation. Once again radiographical findings, patient co-morbidities and wishes must be taken into account.

Note: Open fractures should be managed as per the BOAST open fracture guideline.

Complications

A number of complications may occur as a result of a distal radius fracture or its management.

Early

  • Median nerve neuropathy
  • Ulnar nerve neuropathy
  • Extensor pollicis longus or flexor pollicis longus rupture
  • Compartment syndrome

Medium to late

  • Osteoarthritis
  • Non-union / mal-union
  • Complex regional pain syndrome
  • Metalwork infection
  • Metalwork irritation

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