Wrist Trauma

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Wrist Trauma
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Fractures and Dislocations of the Wrist

• Clinically point tenderness over the wrist with
  gt20 loss of grip strength are good physical
  indicators
• Complex anatomy requires four views for
  interpretation
• Neutral PA, PA in ulnar deviation, medial oblique
  and lateral
• Advanced imaging very useful because fractures
  not always visible

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Normal Anatomy
http//uwmsk.org/RadAnat/WristPALabelled.html
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Distal Radius Fractures

• Fractures may be subtle or even occult
• Alteration of pronator quadratus fat plane is a
  useful indicator of fracture
• Distal radial fractures
• include
• -Colles, Smiths, Bartons,
• Chauffers, Moores,
• torus, slipped radial
• epiphysis

http//radiology.rsna.org/content/244/3/927.full
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Distal Radius Fractures

• Colles fracture- fx. of distal radius with
  posterior angulation of distal fragment
• Usually FOOSH
• Osteoporosis is risk factor, so increased
  incidence in womengt65
• Smith's fracture (reverse
• Colles fracture)- fracture of
• distal radius with anterior
• angulation of distal fragment
• Less common than Colles
• Direct blow or fall on flexed hand

http//imageinterpretation.co.uk/wrist.html
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Distal Radius Fractures

• Bartons fracture (rim fx.)- posterior rim
  fracture of distal radial articular surface with
  associated proximal dislocation of carpals
• Will see overlap of proximal row with articular
  surface of radius
• Chauffeurs fracture (backfire fx., Hutchinson's
  fx.)- fracture of radial styloid
• Caused by avulsion or impaction by scaphoid
• Formerly caused by starting cars with hand cranks

http//www.radiologyassistant.nl/en/476a23436683b
http//radiographics.rsna.org/content/24/4/1009/F1
1.expansion.html
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Distal Radius Fractures

• Moores fracture- fracture of ulnar styloid
  process and dislocation of distal ulna associated
  with Colles fracture
• Torus fracture- buckling of cortex after trauma
• Happens in children
• Can happen in any long bone
• Radiographic sign is bump or
• bulge of cortex

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Distal Radius Fractures

• Slipped radial epiphysis- childhood equivalent of
  Colles fracture
• Hyperextension injury (FOOSH) causes shearing of
  radial epiphysis, which gets displaced
  posteriorly
• Usually has small metaphyseal fragment (corner
  sign), which makes it Salter-Harris II

http//www.oha.or.kr/skr/trauma/trauma4.htm
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Distal Unlar Fractures

• Ulnar styloid process fracture- rare as an
  isolated fracture
• Usually avulsion by ulnar collateral ligament
• More frequently found as associate fracture with
  other injuries
• Distal ulnar shaft fracture- see nightstick
  fracture from forearm fracture section

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Scaphoid Fractures

• Most common carpal bone to fracture
• Usually ages 15 to 40 rare in children
• FOOSH
• Clinical presentation is snuffbox pain with
  swelling
• Most common site for occult fracture
• Classified by anatomic location
• of fracture line
• Waist (70), proximal pole (20)
• and distal pole (10)

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Scaphoid Fractures

• Initially radiographs may be negative
• Repeat x-ray in 10 to 20 days or advanced imaging
  immediately
• MRI makes most sense if US not available
• Complications include
• AVN, nonunion, carpal instability and radiocarpal
  degenerative arthritis

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Scaphoid AVN

• Scaphoid had 2 blood supplies
• Proximal pole is supplied by an artery that
  enters distally
• The more proximal the fracture is, the more
  likely AVN will occur if untreated
• Radiographic signs include increased density
  (dead bone) and fragmentation

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Nonunion

• Missed diagnosis may lead to delay in treatment
• Over time fracture line will widen and margins
  will become smooth and sclerotic

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Carpal Instability

• Follows rupture of scapholunate ligament
• Radiographic features include
• Terry Thomas sign- widening of scapholunate jt.
  space gt4 mm
• Ring sign- rotation of scaphoid
• Loss of parallel joint surfaces

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Radiocarpal Degenerative Arthritis

• Radiographic signs are that of OA anywhere else
  in the body
• OA signs at the radiocarpal joint in the absence
  of trauma suggests diagnosis of CPPD
• SLAC (ScaphoLunate Advanced Collapse) wrist may
  follow if capitate is allowed to migrate
  proximally

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Triquetral Fractures

• 2nd m.c. carpal bone to fracture
• Usually by avulsion from dorsal surface by
  radiocarpal ligament (Fisher fracture)
• Small flake dorsally only identifiable on lateral
  film

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Fractures of Other Carpal Bones

• All may fracture, but unusual unless directly
  traumatized
• Hamate frequently complicated by non-union
• Lunate frequentlyly
• complicated by avascular
• necrosis (Keinböcks disease)

http//orthoinfo.aaos.org/topic.cfm?topica00017
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Dislocations of the Wrist

• Two patterns
• 1. a single bone that dislocates relative to
  remaining carpals
• 2. a single bone that remains in place with the
  surrounding carpals dislocating
• Evaluation of carpal arcs is a useful tool
• Arc 1- proximal articular surfaces of proximal
  row
• Arc 2- distal articular surfaces of proximal row
• Arc 3- proximal surfaces of distal
• carpals (capitate and hamate)
• Disruption indicates dislocation

http//www.radiologyassistant.nl/en/42a29ec06b9e8
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Single Carpal Dislocations

• Lunate dislocation- most common carpal bone to
  dislocate
• On PA film dislocated lunate appears triangular
  (pie sign)
• Rows 2 and three disrupted
• Scaphoid dislocation-
• On PA film, see ring sign and Terry Thomas sign
  as previously described
• Other single carpal dislocations
• unusual and require severe trauma

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Multiple carpal dislocations

• Perilunate dislocation- dorsal displacement of
  all carpals except lunate, which stays in place
• On lateral, capitate does not sit in the lunate
• On PA, capitate overlies lunate
• Trans-scaphoid perilunate dislocation- same as
  above, but with associated scaphoid fracture
• de Quervaines fracture dislocation- anterior
  dislocation of lunate as well as proximal
  fragment of fractured scaphoid

http//www.imageinterpretation.co.uk/wrist.html
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Fractures of 2nd - 5th Metacarpals

• Boxers fracture- transverse fracture of neck of
  second or third metacarpals
• Result of straight jab with fist
• Barroom fracture- transverse fracture of neck of
  fourth or fifth metacarpals
• Result of roundhouse blow from inexperienced
  fighter

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First Metatarsal Fractures

• Bennett's fracture- intra-articular fracture
  through base of the first metacarpal with dorsal
  displacement of the shaft
• A small medial fragment remains at its
  articulation with trapezium
• Rolando's fracture (comminuted Bennets) same as
  above but comminuted
• Transverse fracture- most common fracture of
  first metacarpal
• Doesn't interfere with articulation

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• Distal phalangeal fractures
• Described as transverse, longitudinal, comminuted
  or chip fractures
• Chip fractures occur at posterior or anterior
  corners of phalangeal base
• Posterior chip fracture inactivates extension of
  the DIP joint and produces flexion deformity
  (mallet or baseball finger)
• Middle phalangeal fractures
• Chip fracture at anterior aspect
• of base (Volar plate fracture)

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References

• Yochum, T.R. (2005) Yochum and Rowes Essentials
  of Skeletal Radiology, Third Edition. Lippincott,
  Williams and Wilkins Baltimore.