Orthopedic%20Pitfalls:%20Approach%20to%20Upper%20Limb%20X-rays

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Orthopedic PitfallsApproach to Upper Limb X-rays

• Yael Moussadji, PGY 3
• Dr. Phil Ukrainetz
• Nov 2, 2006

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Objectives

• To review diagnosis and management of upper
  extremity orthopedic injuries
• To highlight injuries that are frequently missed
  or mismanaged
• To review, in detail, orthopedic pitfalls
  including
• Posterior shoulder dislocations
• Elbow fractures
• Forearm fractures
• Wrist injuries

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Anterior Shoulder Dislocations

• Classified according to the final position of the
  humeral head
• Subcoracoid dislocations are most common (70),
  followed by subglenoid (30)
• Subclavicular and intrathoracic are associated
  with violent forces, fractures, and are extremely
  rare

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Clinical Features

• Arm held in slight abduction and external
  rotation by other extremity
• Shoulder may have a squared off appearance, with
  fullness of anterior shoulder
• Patient cannot adduct of internally rotate
  without severe pain
• 5-54 may have axillary nerve injury, assessed by
  testing for sensation over lateral shoulder and
  motor function of deltoid (more accurate)

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Associated Fractures

• Associated fractures in 50
• Most common is the Hill Sachs deformity,
  compression fracture of the posterolateral
  humeral head
• Bankarts lesions may be present in up to 5
• Avulsion fractures of the greater tuberosity
  account for 10-15

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Selective radiology in 100 patients with
suspected shoulder dislocation. The Journal of
Emergency Medicine. Hendey et al, 2006.

• Prospective validation of a previously derived
  clinical decision rule for selective radiography
  of patients with suspected shoulder dislocation
  in the ED
• Pre and post reduction radiographs were ordered
  based on the algorithm incorporating mechanism of
  injury, previous dislocations, and physicians
  clinical certainty of joint position
• 94 of 100 patients had shoulder dislocations, of
  which 59 were recurrent
• 30 had both pre and post films, 45 had either
  pre or post, and 25 had none
• There was a 46 reduction in x-ray utilization,
  with no missed fractures or dislocations, with
  the greatest potential for saving noted in the
  subset of patients with recurrent atraumatic
  dislocations
• Previous studies have indicated that fracture
  dislocations can be predicted by 3 variables
  first time dislocations, blunt traumatic
  mechanism (fall gt 1 flight stairs, assult, MVC),
  age gt40

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Algorithm for Shoulder Radiography in the ED
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Shoulder Reduction

• Traction-counter traction
• Stimson technique
• Patient is placed prone with the affected limb
  hanging downwards in forward flexion at the
  shoulder patient remains in that position with
  5-10 pound weights suspended from the wrist can
  take 15-20 min
• External rotation
• Slow gentle external rotation of the adducted
  arm reduction occurs between 70 and 110 degrees
• Can be done supine or sitting (80 successful)
  over 5-10 min
• Scapular manipulation
• Focus is on repositioning the glenoid fossa (85
  successful)
• Arm held at forward flexion with slight traction
• Superior aspect of scapula is stabilized, while
  the inferior tip is adducted with the thumb

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• Others (Milch, Spaso etc) all employ some degree
  of traction and external rotation to simulate the
  mechanism in which dislocation occurred

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Posterior Shoulder Dislocation

• The most commonly missed joint dislocation in the
  body
• Incidence of 1-4 of all shoulder dislocations
• 79 are incorrectly diagnosed
• Must have a high index of suspicion in order to
  seek out the classic physical findings

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History

• Occurs when the arm is forward flexed and
  slightly internally rotated with axial load
  applied, eg hitting a heavy punching bag or
  striking the dash with arm extended to the front
• Classic history is a significant blow to the
  front of the shoulder, or a FOOSH with the elbow
  extended and humerus internally rotated
• Posterior dislocations are the result of indirect
  forces producing a combination of internal
  rotation, adduction, and flexion
• Can also be encountered in patients with
  seizures, alcohol withdrawal, or electrocution

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Physical Exam

• Generally, patients complain of severe pain (more
  painful than anterior dislocations)
• Patient will usually be sitting with arm held
  tightly across front of trunk, fixed in a
  position of adduction and internal rotation
• External rotation is blocked and abduction is
  severely limited
• The posterior aspect of the shoulder is rounded
  and more pronounced, and the anterior portion
  will be flattened with a prominent coracoid
  process
• Clinical pearl Patients will be unable to
  supinate the palm (always present)

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Radiographs AP view
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AP view

• Absence of the normal elliptical shadow
• On a routine AP view there is usually an overlap
  shadow created by the head of the humerus imposed
  on the glenoid fossa in a posterior dislocation,
  the articular surface of the humeral head is
  posterior to the glenoid, distorting the
  elliptical overlap shadow the inferior third of
  the glenoid fossa usually has no contact with the
  humeral head
• Vacant glenoid sign
• The humeral head normally occupies the majority
  of the glenoid cavity in posterior dislocations
  the head rests behind the glenoid, producing a
  positive rim sign if the space between the
  anterior rim and the humeral head gt6mm, posterior
  dislocation is likely
• The trough line
• An impaction fracture of the humeral head caused
  by posterior rim of glenoid resulting in two
  parallel lines of cortical bone on the medial
  cotext of the humeral head
• Hollowed out or cystic humeral head
• Arm locked in internal rotation, aligning the
  greater and lesser tuberosities

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Shoulder radiographs

• Caution the AP view does not represent a true AP
  of the glenohumeral joint (scapula lies at 45
  degrees, angulating the glenohumeral joint space
  anteriorly at 45 degrees)
• Therefore loss of the joint space in a posterior
  dislocation may not be visualized on a normal AP
  of the shoulder
• An axillary or scapular view is required

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Scapular lateral

• Most clinically useful AND patient friendly
• Virtually diagnostic of posterior shoulder
  dislocation
• Taken sitting or standing or supine with arm left
  undisturbed
• Anterolateral portion of shoulder placed against
  the cassette
• X-ray beam passes tangentially across
  posterolateral chest parallel to and down from
  spine of scapula onto cassette
• This represents a true lateral of the scapula,
  and therefore the glenohumeral joint

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Scapular lateral

• In the lateral view, the scapula projects as the
  letter Y
• The vertical stem of the Y is the body of the
  scapula the upper fork is formed by the juncture
  of the coracoid and the acromion process
• The glenoid is located at that junction
• In a posterior dislocation, the humeral head will
  be posterior to the glenoid

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Axillary lateral

• Requires the patient to lie supine and abduct the
  arm 70-90 degrees with cassette above shoulder
  and tube near hip
• 2 modified axillary views available in patients
  who are in too much pain to tolerate

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Axillary lateral

• Humeral head posterior to glenoid fossa
• Dots and arrows indicate trough lines (reverse
  Hill Sacks lesions)
• B Bankhart fracture fragment

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Management

• Management depends on the presence of and size of
  the anterior impression fracture incidence of
  co-existent fractures is 50
• When humeral head lesion lt20 of articular
  surface, closed reduction may be attempted
• Many may go on to need general anesthetic
• Place patient supine and apply traction to the
  adducted arm in the line of deformity
• While applying traction, gently lift the humeral
  head back into the glenoid fossa
• If the head remains locked on the glenoid rim,
  apply lateral traction on the upper arm using a
  folded towel
• Traction is maintained while the arm is then
  slowly externally rotated
• Do not force the arm into external rotation this
  may fracture the humerus
• The arm is then immobilized in external rotation
  and slight abduction

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Luxatio Erecta(a.k.a. inferior shoulder
dislocation)

• Comprises 0.5 of all shoulder dislocations, and
  can be misdiagnosed as an anterior dislocation
• Mechanism is injury involves hyperabduction of
  arm at shoulder with extension at elbow while
  forearm pronated
• Direct violent force applied to superior
  shoulder, causing inferior movement of humeral
  head relative to glenoid fossa disrupting the
  inferior glenohumeral capsule

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Clinical presentation

• Patients usually present with arm hyperabducted
  at shoulder and flexed at elbow with forearm
  resting behind the head
• Glenoid fossa is empty and humeral head is
  palpated in axilla
• AP view demonstrates inferior displacement of
  humeral head

• Axillary view

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Management

• Closed reduction with muscle relaxation and
  anesthesia
• In-line traction to the fully abducted arm with
  firm cephalad pressure on humeral head
• Counter-traction using rolled bed sheet placed
  superior to shoulder
• Once humeral head reduced, arm adducted towards
  body and forearm supinate
• Outpatient orthopedic referral
• Associated injuries include rotator cuff
  injuries, fractures of the clavicle, coracoid,
  acromion, inferior glenoid, greater tuberosity of
  humerus (80 of cases)
• 60 suffer axillary nerve injury

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Supracondylar fractures

• Bony injury of distal humerus proximal to the
  epicondyles
• Mean age of 7 years, rare beyond 15
• Similar injury mechanisms in adults produce
  posterior elbow dislocations
• Classified as flexion type or extension type
  (95)
• Extension type supracondylar fractures result
  from FOOSH with elbow fully extended force of
  impact directed forward fracturing the anterior
  aspect of the distal humerus contraction of the
  triceps pulls the distal fragment posteriorly and
  proximally

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Radiography

• Type I
• Minimal to no displacement
• Type II
• Incomplete injury, minimal to moderate
  displacement and/or intact posterior cortex
• Type III
• Complete displacement of fragment with posterior
  cortical disruption

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Occult fracture

• Anterior humeral line should bisect the middle of
  the capitellum in a supracondylar fracture, the
  line will strike the anterior third or miss it
  entirely
• Fat pad sign results from swelling adjacent to
  the distal humerus the posterior fat pad is
  never seen in an uninjured patient and is
  associated with fracture in 90

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Management

• Type I
• Mechanically stable splint for pain control and
  comfort
• Type II
• Reduction, preferably by ortho (yeah right)
• Cast at 120 degrees of flexion
• Type III
• ED reduction
• Associated with loss of arm length, deformity,
  neurovascular compromise
• Apply traction at wrist in line with upper
  extremity with thumb in up position while
  correcting any medial or lateral deformity
• When arm length restored, slowly and gently flex
  elbow to 100 degrees
• Immobilize medially displaced fractures with
  forearm pronated and laterally displaced
  fractures with forearm supinate

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Radial HeadFractures

• Usually results from FOOSH in adults
• Impact transmitted axially, forcing radial head
  against capitellum
• X-ray may detect fracture or only pathological
  fat pads suggestive of occult fracture
• Any irregularity in radial head, especially in
  association with fat pads is a radial head
  fracture until proven otherwise

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Radial Head Mason Classification

• Type I
• undisplaced
• Type II
• Minimally displaced
• Type III
• comminuted
• Type IV
• Fracture-dislocation

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Management

• Type I
• Treat symptomatically with sling and early ROM
• Type II
• Treat as Type I patients may require radial head
  excision if fails ROM maneuvering
• Type III
• Early ortho follow-up for excision of radial head
• Type IV
• Reduction and early surgical excision
• Outcomes excellent

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Galeazzi and Monteggia fracture dislocations

• Dislocation at the elbow or wrist may accompany
  any forearm fracture
• Monteggia pattern of injury consists of a
  fracture of proximal third of ulna with
  dislocation of radial head
• Galeazzi pattern of injury consists of radius
  fracture, most often at junction of middle and
  distal third, with dislocation at DRUJ

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Monteggia

• Proximal dorsally angulated ulna fracture
• Radiocapetellar line misses the capitellum
  indicating a proximal radial head dislocation

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Galeazzi

• Comminuted distal radius fracture
• Subtle disruption of DRUJ evident by shortened
  radius and loss of overlap between radius and ulna

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Mechanism

• Can be caused by low energy (FOOSH) while
  hyperpronated or high energy (MVC)
• Galeazzi is three times more common miss rate of
  up to 50 in diagnosis quoted in some studies
• Monteggia fractures result in an ulnar shaft
  fracture with an anterior radial head dislocation
  in 60
• Galeazzi fractures usually occur distal to biceps
  tuberosity and proximal to 4cm from distal
  radius with displaced radial shaft fracture,
  DRUJ disruption is common but frequently subtle
• May be purely ligamentous, or may involve
  fracture of ulnar styloid

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Presentation

• Monteggia
• Extremely limited ROM of elbow, especially
  flexion and supination
• Dislocated radial head may be palpable
• Deep branch of radial nerve may be affected
  resulting in weakness of extension of
  fingers/thumb
• Galeazzi
• Resist any attempts at pronation and supination
• Ulnar styloid process may be prominent
• However, in nondisplaced fractures the patient
  may not complain of any wrist pain

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Radiography Monteggia

• Ulna fracture usually clearly evident
• ALWAYS measure the radiocapitellar line to avoid
  missing a radial head dislocation
• If the ulnar fracture is angulated, the apex of
  angulation points in the same direction as the
  dislocation

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Radiography Galeazzi

• Radius fractured and shortened
• Increased space between distal radius and ulna on
  PA (should not be wider than 1-2mm)
• On lateral, fractured radius angulated dorsally
  and ulna appears dorsally displaced (normally
  overlies the radius)
• Inability of the tech to get a true lateral
  should raise suspicion of injury

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Management

• Monteggia fractures can be successfully treated
  in children with closed reduction and supinated
  long arm splinting
• More severe injury in adults, required ORIF
• Galeazzi in particular is prone to poor outcome
  if missed (gt90)
• Treated with ORIF of fracture and pin or open
  fixation of DRUJ

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Wrist Sprain?
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Wrist Injuries

• The most common but inaccurate diagnosis made in
  wrist injuries is wrist sprain
• This should be a diagnosis of exclusion
• Commonly missed injuries include scaphoid
  fractures, scapholunate dissociations, lunate and
  perilunate injuries, DRUJ dislocations, hamate
  hook fractures, and triquetral avulsion fractures

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Clinical Approach

• Demonstration of specific point tenderness is the
  most important diagnostic test, so know your
  anatomy
• Anatomic snuffbox sits between the extensor
  pollicus longus and extensor pollicus brevis when
  the thumb is radially abducted body of scaphoid
  is palpated here
• Scaphoid tuberosity palpable at the base of the
  thenar muscles on palmar aspect of wrist
• Pisiform palpable at the junction of the flexor
  carpi ulnaris and volar wrist crease just distal
  to this lies the hook of the hamate
• On dorsal wrist palpate Listers tubercle the
  scapholunate ligament is just distal to this
• Just distal to ulnar head and radial to its
  styloid lies the lunotriquetral junction

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Scaphoid fractures

• Accounts for 60-70 of all wrist fractures, and
  is the most commonly missed injury
• Scaphoid links the proximal and distal carpal
  rows and is the principle bony block to wrist
  extension
• Classic history is a FOOSH with hyperextension at
  the wrist in 97 of cases
• Immediate pain, minimal swelling, and patient is
  able to continue on with daily activities
• Palpation in the anatomic snuffbox is the most
  reliable diagnostic maneuver

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Scaphoid fractures

• Fracture of the middle third is most common
  (80), followed by proximal third (15), distal
  third (4) and distal tubercle (1)
• Propensity for nonunion and AVN caused by blood
  supply which arises distally
• Proximal bone is completely dependent on this
  blood supply and most at risk
• Common associated injuries include fractures of
  distal radius, lunate, or radial head median
  nerve injury has also been described
• 10-20 of fractures are not visible on initial
  x-rays

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X-rays

• Scaphoid view positions wrist in ulnar deviation,
  placing scaphoid in extended position, allowing
  you to view the entire length of the scaphoid
• Also accentuates any scapholunate dissociation

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Management

• Treat all suspected fractures as though one
  exists, with thumb spica splint and f/u in 7-10
  days for reassessment and repeat X-rays
• 15 are ultimately shown to have a fracture
• For confirmed fractures, treat with long arm
  thumb spica splint with hand clinic follow-up in
  7 days
• Consult a hand surgeon on presentation if any
  significant angulation, displacement, or
  comminution

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Lunate and Perilunate Injuries

• Results from similar hyperextension mechanisms
• Perilunate dislocations are more common, and
  lunate dislocations are more severe
• Most common mechanism is a high energy FOOSH,
  followed by MVC and motorcycle crashes
• Accounts for 10 of all carpal injuries
• Associated injuries include fractures of the
  radial styloid, scaphoid, capitate and
  triquetrum the presence of theses should alert
  you to the possibility of an occult perilunate
  injury

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Lunate and Perilunate Injuries

• The hallmark of perilunate dislocation is a
  dislocation of the head of the capitate from the
  the distal surface of the lunate, most often
  dorsally
• The defining feature of a lunate dislocation is
  disruption between the lunate and lunate fossa of
  the distal radius
• All are a progression of the same pathologic
  process
• The mechanism is a progressive pattern of carpal
  ligamentous injury caused by wrist
  hyper-extension and ulnar deviation causing 4
  distinct stages of injury beginning with a
  scapholunate joint disruption and proceeding
  around the lunate

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Stage I

• Scapholunate dissociation, resulting in widening
  of scapho-lunate joint (most common injury),
  which can be seen better on a clenched fist view
• A gap of 2mm of less is considered normal
• Can be associated with rotary subluxation of
  scaphoid resulting in signet ring sign

• Terry Thomas sign

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Stage II

• Perilunate dislocation, best seen on lateral
  wrist
• Capitate is dislocated dorsally
• PA usually demonstrates overlap of distal and
  proximal carpal rows and may demonstrate an
  associated scaphoid fracture

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Stage III

• Similar to stage II, but with dislocation of
  triquetrum, best seen on PA view with overlap of
  the triquetrum on the lunate (due to scaphoid and
  triquetral malrotation)

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Stage IV

• Lunate dislocation
• Triagular piece of pie sign on PA view as
  lunate rotates volarly
• Laterally, this appears spilled teacup
• The capitate lies posteriorly to the lunate,
  which is no longer articulating with the radius

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Approach to the Wrist X-ray PA view

• On the PA view, identify the three arcs
• First is the radiocarpal arc disruption here
  suggests a lunate dislocation
• Second is the midcarpal row disruption suggests
  a perilunate dislocation
• Third is the proximal arc of the distal carpal
  row disruption here suggests a carpal
  dislocation or fracture

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The Lateral Wrist

• The radius, lunate and capitate should all line
  up in a row

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Distal Radioulnar Joint Disruption

• Isolated injuries occur from falls, twisting
  injuries, or suddenly lifting heavy loads with
  wrist outstretched, either in hyperpronation or
  hypersupination
• The radius and carpus dislocate about the ulna
  injuries are classified according to position of
  ulna relative to radius
• Patients complain of a painful loss of forearm
  rotation
• Presents with an asymmetrically prominent distal
  ulna dorsally dislocated with loss of supination,
  or wrist narrowed in AP diameter with fullness of
  palmar aspect, dorsal sulcus, and limited
  pronation
• Primarily a clinical diagnosis
• Ulnar head should be reduced and forearm
  immobilized in full supination with above elbow
  sugar tong splints if dorsally dislocated volar
  dislocations also require reduction and
  immobilization in pronation, but are more
  mechanically stable

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Hamate Hook Fractures

• Occurs from fall on dorsiflexed wrist or through
  direct forces applied to the hypothenal eminence
  by a raquet or bat
• Patients complain of a weak or painful grip, and
  be maximally tender just distal and radial to the
  pisiform
• Carpal tunnel view is the best way to visualize
  the fracture, but if suspected, may need CT scan
• Treat with short arm cast for 4-6 weeks (short
  arm volar splint is appropriate) and ortho
  referral

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Triquetral Fractures

• Usually from a direct blow to the hand or a FOOSH
  (ulnar styloid hits the triquetrum, resulting in
  a dorsal chip fracture)
• Localized tenderness over dorsal wrist distal to
  ulnar styloid
• Seen best on the lateral wrist as a drosal chip
  fragment
• Heals well in short arm splint for 3-4 weeks