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Fracture of the Bones of the Forearm

Both-Bones Forearm Fracture

  • Definition – radial and ulnar shaft fracture

Epidemiology

  • Bimodal age distribution
    • Males between 10-20 years
    • Females over 60 years

Etiology

  • Direct blow to forearm
  • Motor vehicle accidents
  • Falls from height

Anatomy

  • Interosseus membrane (IOM) – occupies space between radius and ulna, comprised of 5 ligaments
    • Central band, accessory band, distal oblique bundle, proximal oblique cord, dorsal oblique accessory cord

Classification

  • OTA classification
    • Types – A (simple); B (wedge); C (multifragmentary)

Clinical features

  • Pain and swelling
  • Loss of forearm function
  • Paraesthesias – can indicate nerve involvement
  • Pain with passive movement of fingers – can be impending compartment syndrome

Diagnosis

  • X-ray

Treatment

  • Cast/brace immobilisation
  • ORIF – most patients require this
    • Plus bone grafting – in open fractures with significant bone loss
  • Intramedullary nailing

Monteggia Fracture

  • Definition – proximal 1/3 ulna fracture with associated radial head dislocation

Epidemiology

  • More common in children – 4-10 years old

Etiology

  • Fall on an outstretched hand with the forearm in excesses pronation

Classification –   Bado classification

  • Type I (extension type) – ulna shaft angulates anteriorly and radial head dislocates anteriorly
  • Type II (flexion type) – ulna shaft angulates posteriorly and radial head dislocates posteriorly
  • Type III (lateral type) – ulna shaft angulates laterally and radial head dislocates to the side
  • Type IV (combined type) – ulna shaft and radial shaft are both fractured, and radial head is dislocated

Clinical features

  • Pain and swelling at elbow joint
  • Loss of ROM at elbow
  • Posterior interosseous nerve (PIN) syndrome
    • Weakness of thumb extension
    • Weakness of MCP extension

Diagnosis

  • X-ray
  • CT

Treatment

  • Closed reduction – more successful in children
  • ORIF of ulna shaft – usually restores radial dislocation as well
  • ORIF of ulna shaft and open reduction of radial head – when ORIF of ulna fails to reduce radial head

Galeazzi Fracture

  • Definition – fracture of distal 1/3 radius and associated distal radioulnar joint (DRUJ) injury

Epidemiology

  • More common in males

Etiology

  • Fall on an outstretched hand with forearm in pronation

Anatomy – of DRUJ

  • Sigmoid notch – found on the ulnar border of the radius, articulates with the ulnar head
  • Volar and dorsal radiolunar ligaments – stabilise the DRUJ
Classification – according to position of distal radius

  • Type I – dorsal displacement (more common)
  • Type II – volar displacement

Clinical features

  • Pain, swelling, deformity at fracture site and wrist joint
  • Wrist pain due to DRUJ instability
  • Reduced ROM
  • Anterior interosseous nerve palsy – paralysis of FPL and FDP
    • Presents as loss of pinch mechanism between the thumb and index finger
  • Injury to the radial nerve – presents as wrist drop

Diagnosis

  •  X-ray – fracture of distal 1/3 radius, widening of DRUJ, dorsal or volar displacement

Treatment

  • ORIF of radius with reduction and stabilisation of DRUJ
    • Operative treatment is nearly always needed in adults

Distal Radius Fractures – Colles’, Smith’s, Barton’s

Epidemiology

  • Most common fractures in adults
  • Female preponderance
  • Most fractures are intra-articular

Etiology

  • Younger patients – high energy trauma
  • Older patients – low energy trauma, e.g. fall on an outstretched hand
  • Osteoporosis is the main risk factor

Anatomy

  • Distal radius is responsible for 80% of axial load
  • It articulates with the scaphoid (via scaphoid fossa), lunate (via lunate fossa) and distal ulna (via ulna/sigmoid notch)
Types
  • Colles’ fracture – low energy, dorsally displaced, extra-articular fracture
  • Smith’s fracture – low energy, volarly displaced, extra-articular fracture
  • Barton’s fracture – fracture of radiocarpal joint with intra-articular fracture involving volar or dorsal lip

Clinical features

  • Wrist pain, swelling, deformity
  • Ecchymosis
  • Diffuse tenderness
  • Range of motion limited due to pain

Diagnosis

  • X-ray
  • CT – for surgical planning
  • MRI – for soft tissue injuries

Treatment

  • Closed reduction and splint/cast immobilisation
  • CRPP
  • ORIF – for unstable, comminuted fractures; severe osteoporosis

Night-stick Fracture

  • Definition – isolated fractures of the ulna

Epidemiology

  • More common in men under 40 years and women over 60

Etiology

  • Most commonly due to a defensive injury – especially when the person is holding the arm up to protect their head from injury
  • Osteoporosis is a risk factor

Clinical features

  • Pain and swelling
  • Loss of forearm and hand function
  • Gross deformity

Diagnosis

  •  X-ray
  • CT – rarely necessary

Treatment

  • Cast immobilisation – for <50% displacement
  • ORIF – for displaced or open fractures
    • Risk of non-union is high despite prompt treatment
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