Orthopedic Pitfalls:Approach to Upper Limb X-rays

Yael Moussadji, PGY 3Dr. Phil UkrainetzNov 2, 2006

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

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

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)

Associated Fractures

Associated fractures in 50%

Most common is the Hill Sachs deformity, compression fracture of the posterolateral humeral head

Bankart’s lesions may be present in up to 5%

Avulsion fractures of the greater tuberosity account for 10-15%

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 > 1 flight stairs, assult, MVC), age >40

Algorithm for Shoulder Radiography in the ED

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

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

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

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

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)

Radiographs: AP view

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 >6mm, 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

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

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

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

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

Axillary lateral Humeral head

posterior to glenoid fossa

Dots and arrows indicate trough lines (reverse Hill Sack’s lesions)

B = Bankhart fracture fragment

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 <20% 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

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

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

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

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

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

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%

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

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

Radial Head #Mason Classification Type I

• undisplaced

Type II• Minimally displaced

Type III• comminuted

Type IV• Fracture-dislocation

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

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

Monteggia Proximal dorsally

angulated ulna fracture Radiocapetellar line

misses the capitellum indicating a proximal radial head dislocation

Galeazzi Comminuted distal

radius fracture Subtle disruption of

DRUJ evident by shortened radius and loss of overlap between radius and ulna

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

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

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

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

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 (>90%) Treated with ORIF of fracture and pin or

open fixation of DRUJ

Wrist Sprain?

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

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 Lister’s tubercle; the scapholunate ligament is just distal to this

Just distal to ulnar head and radial to its styloid lies the lunotriquetral junction

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

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

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

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

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

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

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

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

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)

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

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

The Lateral Wrist The radius, lunate and

capitate should all line up in a row

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

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

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