Wrist Trauma
Fractures and Dislocations of the Wrist
• Clinically point tenderness over the wrist with
>20% 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
Normal Anatomy
http://uwmsk.org/RadAnat/WristPALabelled.html
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’, Smith’s, Barton’s,
Chauffer’s, Moore’s,
torus, slipped radial
epiphysis
http://radiology.rsna.org/content/244/3/927.full
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
women>65
• 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
Distal Radius Fractures
• Barton’s 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
• Chauffeur’s 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://radiographics.rsna.org/content/24/4/1009/F11.expansion.html
http://www.radiologyassistant.nl/en/476a23436683b
Distal Radius Fractures
• Moore’s 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
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
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
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%)
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
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
Nonunion
• Missed diagnosis may lead to delay in treatment
• Over time fracture line will widen and margins
will become smooth and sclerotic
Carpal Instability
• Follows rupture of scapholunate ligament
• Radiographic features include:
– Terry Thomas sign- widening of scapholunate jt.
space >4 mm
– Ring sign- rotation of scaphoid
– Loss of parallel joint surfaces
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
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
Fractures of Other Carpal Bones
• All may fracture, but unusual unless
directly traumatized
• Hamate frequently complicated by nonunion
• Lunate frequentlyly
complicated by avascular
necrosis (Keinböck’s disease)
http://orthoinfo.aaos.org/topic.cfm?topic=a00017
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
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
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
http://www.imageinterpretation.co.uk/wrist.html
• Trans-scaphoid perilunate dislocation- same as
above, but with associated scaphoid fracture
• de Quervaine’s fracture dislocation- anterior
dislocation of lunate as well as proximal fragment of
fractured scaphoid
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
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 Bennet’s) same
as above but comminuted
• Transverse fracture- most common fracture of first
metacarpal
– Doesn't interfere with articulation
• 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)
References
• Yochum, T.R. (2005) Yochum and
Rowe’s Essentials of Skeletal
Radiology, Third Edition. Lippincott,
Williams and Wilkins: Baltimore.