Transcript Fractures and dislocations of the wrist - cox

Fractures and dislocations of
the wrist
Dr Ihab Rassem
Lecturer of radiology Ain Shams University
Cairo, Egypt
Radiographic views
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Dorsovolar (PA)
Lateral
Dorsovolar with ulnar deviation (scaphoid)
Supinated oblique (pisiform, pisotriquetral
joint)
Pronated oblique (triquetral)
Carpal tunnel (hook of hamate, pisiform,
volar trapezium)
Dorsovolar with ulnar deviation
Supinated oblique
Pronated oblique view
Carpal Tunnel view
Carpal bones fractures
Scaphoid fracture
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Most common carpal bone to be fractured
Age 15-30
Fall on outstretched arm
Classification
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Distal pole and tubercle 5-10%
Proximal pole 15-20% (nonunion & AVN)
Waist 70-80%
Scaphoid fracture
PA
PA with ulnar
deviation
Nonunited scaphoid fracture
Scaphoid fracture seen in MRI
AVN of scaphoid
Fracture of triquetral
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Usually a subtle fracture
Best seen in the lateral or pronated
oblique view.
Hamate fractures
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Usually arise due to direct blow to the volar
aspect of the wrist
Two types
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Fracture of the hook (hamulus) of hamate:
Fracture of the body of hamate
Hook of hamate is seen in dorsovolar view as a
cortical ring. Absence, indistinctness, or sclerosis
of this ring suggests hamulus fracture (eye sign)
Carpal tunnel view is also helpful may may be
difficult due to pain
Fracture of pisiform bone
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Rare
Results from fall on the outstretched hand
or use of the hand as a hammer to strike
an object
May be isolated or co-exist with other
bone fractures
Best seen in supinated oblique or carpal
tunnel view
Fractrue of the capitate
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Results from fall on outstretched hands or
form direct blow
Usually associated with other carpal bone
injuries particularly scaphoid fracture and
perilunate dislocation
Waist (neck) of capitate is the most
common site
PA view
Tomogram
Fracture of the lunate bone
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Usually result from fall on the dorsiflexed
wrist or ecessive push on the heal of the
hand
Often associated with perilunate
dislocation.
More commonly occur as a pathologic
fracture in the setting of Kienböck disease
Kienböck Disease
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Avascular necrosis of the lunate bone,
May be related to repeated trauma
May be related to negative ulnar variance
Classification
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Stage I: radiograph normal, transverse linear fracture
on tomography
Stage II: increased density with some flattening on
the radial side
Stage III: marked decrease in height of lunate with
proximal migration of capitate
Stage IV:radiocarpal joint osteoarthritis
Stage I
Stage II
Stage III
Stage IV
Fracture of the trapezium
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Most commonly loading injury in the
setting oa adducted thumb where the first
metacarpal is driven into trapezium
Associated with fracture of the 1st
metacarpal base and subluxation or
dislocation of 1st carpometacarpal joint
Fracture trapezoid
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Rare fracture.
Associated with dislocation of the 2nd
metacarpal bone
Carpal bones dislocations
Normal anatomical relations
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Lateral view with wrist in neutral position:
radius, lunate, capitate, 3rd metacarpal
should be in the same line.
Normal anatomical relations
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Dorsovolar view with wrist in neutral
postion: 3 smooth unbroken arcs should
be seen (Gilula arcs)
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Arc I: proximal articular surfaces of the
scaphoid,lunate,& triquetrum
Arc II: distal concavities of scaphoid, lunate,
& triquetrum
Arc III: proximal convexities of capitate &
hamate
Vulnerable zones theory
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Dislocations around the lunate can occur in two
patterns.
Lesser arc injury pattern: consist of pure ligamentous
injuries leading to dislocations
Greater arc injury pattern: consist of dislocation in
addition to fracture of one or more of the bones around
the lunate (scaphoid, trapezium, capitate, hamate,
triquetrum).
In cases of greater arc injury you mention the prefix
trans- followed by the name of the fractured bone then
the dislocation e.g. trans- scaphoid perilunate dislocation
Greater arc =blue
lesser arc = red
Dislocations around the lunate
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Occur in sequential stages according to
the severity of trauma
Stage I: Scapholunate dissociation;
rotatory subluxation of scaphoid
Stage II: perilunate dislocation
Stage III: midcarpal dislocation
Stage IV: lunate dislocation
Dislocations around the lunate
Scapholunate dissociation
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Results from injury of the scapholunate
ligament
Radiographicaly diagnosed by Terry
Thomas sign due to widening of the space
between the scaphoid and lunate more
than 2 mm
Terry Thomas sign
Rotatory subluxation of scaphoid
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Related condition to scapholunate dissocaition
where there is in addition rotation of the
scaphoid along its long axis
Radiographically diagnosed by signet ring sign:
volar tilt of the scaphoid makes it appear
foreshortened with its tuberosity seen end on
giving a cortical ring.
Radiographs in dorsovolar view should be in the
neutral position or with ulnar tilt for this sign to
be reliable one
Neutral position
signet ring sign
Radial tilt
Normal scaphoid
Perilunate dislocation
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On lateral view:
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Dorsal or volar dislocation of the capitate.
Lunate remains in articulation with the radius
although there may be some degree of tilt
On dorsovolar view
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Crowdening of the proximal and distal carpal
rows
Break in arcs II and III at the site of the
capitate
Lunate dislocation
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On lateral view
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Axis of lunate is titled away from the articular
surface of radius (spilled tea cup sign)
Capitate remains in normal alignment with
radius and 3rd metacarpal
On dorsovolar view
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Disruption of arc II while arc III remains
intact
DISI
VISI
Thank you