Transcript Radiography: Hip, Pelvis & Shoulder

X-rays:
Pelvis, Hip & Shoulder
Feb. 22, 2006
J. Huffman, PGY-1
Thanks to Dr. J. Lord
Also thanks to Moritz, Adam and Steve Lan for some borrowed slides and
images
Goals:
As per instructions, this is a radiology talk ONLY.
The focus is on reading as many films as possible.
Therefore, try your best to describe what you see
as you would when on the phone with a
consultant.
No epidemiology
No management
No associated injuries (i.e. vascular injury with
pelvic #)
Outline
1. Pelvis
a)
b)
c)
d)
Anatomy
Views
Classification of fractures
Practice
2. Hip
a)
b)
c)
d)
e)
Anatomy
Views
Fractures
Dislocations
Practice
3. Shoulder
a)
b)
c)
d)
e)
Anatomy
Views
Dislocations
Fractures
Practice
Pelvis: Anatomy
 Pelvis = sacrum, coccyx +
2 inominate bones
 Inominate bones = ilium,
ischium, pubis
 Strength from ligamentous
+ muscular supports
Pelvis: Anatomy
 Anterior Support:
 ~40% of strength
 Symphysis pubis
 Fibrocartilaginous joint
covered by ant & post
symphyseal ligaments
 Pubic rami
 Posterior Support:
 ~60% of strength
 Sacroiliac ligament complex
 Pelvic floor
 Sacrospinous ligament
 Sacrotuberous ligament
 Pelvic diaphragm
Pelvis: Anatomy
 Very strong posterior ligaments
 Disruption of these is the cause of mechanical instability
Arteries and veins lie adjacent to posterior arch
Pelvis: Anatomy
 Divided into 3 columns:
 Anterior superior column
(= ilium)
 Anterior inferior column
(= pubis)
 Posterior Column
(= ischium)
Pelvis: Imaging
 Plain films
 AP
 Inlet view / Outlet view
 Judet view (oblique – shows columns, acetabulum)
AP alone ~90% sensitive; combined w/ inlet/outlet views ~94%
 Limited in ability to clearly delineate posterior injuries
Pelvic films are NOT necessary in pts with normal physical
exam, GCS >13, no distracting injury and not intoxicated
At least one study shows clinical exam reliable in EtOH
 Gonzalez et al. J Am Coll Surg. 2002; 194: 121-5
 CT scans
Evaluates extent of posterior injury better
Superior imaging of sacrum and acetabulum
More detailed info about associated injuries
Pelvis: Imaging - Acetabulum
a) Arcuate line
b) Ileoischial line
c) Radiographic U (teardrop)
d) Acetabular roof
e) Anterior lip of acetabulum
f) Posterior lip of acetabulum
Pelvis: Imaging - Acetabulum
Pelvis: Imaging – Normal Inlet
Pelvis: Imaging – Normal
Outlet
Pelvis: Imaging
Radiographic clues to posterior arch fractures:
L5 transverse process avulsion* (iliolumbar
ligament)
Avulsion of the lower, lateral sacral lip*
(sacrotuberous ligament)
Ischial spine avulsion* (sacrospinous ligament)
Assymmetry of sacral foramina
Displacement at the site of a pubic ramus
fracture
Pelvis:
Fracture Classification
Systems
 2 most common are Tile and Young systems
 Tile Classification system:
 Advantages
Comprehensive
Predicts need for operative intervention
 Disadvantages
Does NOT predict morbidity or mortality
 Young Classification System:
 Advantages
Based on mechanism of injury  predicts ass’d injury
Estimates mortality
 Disadvantages
Excludes more minor injuries
Tile Classification System
Type A:
 Stable: Posterior structures intact
Type B:
 Partially stable: Posterior structures
incompletely disrupted
Type C:
 Unstable: Posterior structures
completely disrupted
*Each type further classified into
3 sub-types based on fracture.
Tile Classification System
 Type A: Stable pelvis: post
structures intact
 A1: avulsion injury
 A2: iliac wing or ant arch #
 A3: Transverse sacrococcygeal #
Tile Classification System
 Type B: Partially stable pelvis:
incomplete posterior structure
disruption
 B1: open-book injury
 B2: lateral compression injury
 B3: contralateral / bucket handle
injuries
Tile Classification System
 Type C: Unstable pelvis:
complete disruption of posterior
structures
 C1: unilateral
 C2: bilateral w/ one side Type B,
one side Type C
 C3: bilateral Type C
Young Classification System
 Lateral Compression
 Anteroposterior Compression
 Vertical Shear
 Combination
*LC and APC further classified into 3
sub-types based on fracture
Young Classification System:
 Lateral Compression
(50%)
 transverse # of pubic rami,
ipsilateral or contralateral to
posterior injury
LC I – sacral compression
on side of impact
LC II – iliac wing # on side
of impact
LC III – LC-I or LC-II on
side of impact w/
contralateral APC injury
Young Classification System:
 AP Compression (25%)
 Symphyseal and/or Longitudinal
Rami Fractures
APC I – slight widening of the
pubic symphysis and/or
anterior SI joint
APC II – disrupted anterior SI
joint, sacrotuberous, and
sacrospinous ligaments
APC III – complete SI joint
disruption w/ lateral
displacement and disruption of
sacrotuberous and
sacrospinous ligaments
Young Classification System:
 Vertical Shear (5%)
 Symphyseal diastasis or
vertical displacement
andteriorly and posteriorly
 Combined Mechanism
 combination of injury
patterns
Young Classification System:
Morbidity and Mortality
Tile A1
Tile B1 / Young APC II
Tile C1/ Young VS
Tile A1
No Fracture, just an IUD
Tile B3 / Young APC
Tile A2 / Young LC II
No #, just SC air from rib fractures
Pelvis: Acetabular Fractures
 Four Categories:
1. Posterior lip fracture
 Commonly assoc. w/ posterior hip dislocation
2. Central or transverse fracture
 Fracture line crosses acetabulum horizontally
3. Anterior column fracture
 Disrupts arcuate line, ileoischial line intact, U displaced
medially
4. Posterior column fracture
 Ileoischial line disrupted and separated from the U
 Judet (oblique views) or CT helpful if suspicious
Pelvis: Imaging - Acetabulum
Focus on the acetabular fractures.
Posterior Column #
Posterior Column #
Anterior Column #
Bilateral Anterior Column #
Posterior Lip #
Central (Transverse) fracture
Proximal Femur & Hip
Proximal Femur & Hip: Injuries
Fractures:
 Femoral neck, intertrochanteric, femoral head,
greater & lesser trochanter, subtrochanteric
Dislocations:
 Anterior, posterior, central, (inferior)
Proximal Femur: Anatomy
Ward’s Triangle
Proximal Femur: Images
 AP
 Internal rotation!
 Lateral
 Cross-table Lateral
 Frog-leg Lateral
Proximal Femur: Images
Cross-table lateral view
* = ischial tuberosity
Proximal Femur:
Fracture Classification
1. Relationship to capsule
 Intracapsular, extracapsular
2. Anatomic location
 Neck, trochanteric, intertrochanteric, subtrochanteric,
shaft
3. Degree of displacement
Proximal Femur:
Approach to the film
1. Shenton’s Line
 Femoral neck #
 Dislocation
2. ‘S’ and ‘Reverse S’ patterns
3. Position of lesser trochanter
 Dislocation
4. Femoral head size
 Dislocation
5. Trace trabecular groups
Left posterior dislocation – note Shenton’s line
Proximal Femur:
Approach to the film
Lowell’s ‘S’ patterns
Impacted femoral neck #
Hip: Dislocations
Etiology
 Adults: high energy mechanism (MVA)
 Elderly, prosthetic joints, kids < 6yo: minor mech
Types:
 Posterior >> anterior > central (> inferior)
Orthopedic emergencies:
 Urgent reduction after ABC’s / stabilization
 Significant neurovascular complications
 Often multiple associated injuries
 Mandate CT post-reduction
Hip: Dislocation imaging
Plain Films: ant vs. post dislocations
 Femoral head size
Posterior dislocation  femoral head smaller
 Lesser trochanter visibility
Post dislocation  adduction & internal rotation, lesser
trochanter not seen
Ant dislocation  external rotation; lesser trochanter
clearly visible
CT
 Indicated for more detailed evaluation of femoral
neck, intra-articular #’s, and acetabulm
Anterior dislocation
Posterior dislocation
Lesser trochanter
Proximal Femur: Fractures
Femoral head fracture:
 Usually 2° to dislocation
 Pipkin classification
Femoral neck fracture:
 Can be subtle (check lines, ‘S’)
 Describe as nondisplaced (15-20%) vs displaced
Intertrochanteric fracture:
 High energy or weak bone
 Classify according to number of bone fragments
(e.g. two-part)
Displaced femoral neck fracture
Nondisplaced femoral neck #
Two-part intertrochanteric fracture
Three-part intertrochanteric #
Proximal Femur: Fractures
Isolated trochanter fracture:
 Rare (women more than men)
 Direct fall or avulsion by iliopsoas
 Outpt management
Subtrochanteric fracture:
 #’s b/w lesser trochanter & point 5 cm distal
 Common site for pathologic fractures
 Vague symptoms
Occult fracture:
 ~%5 of hip fractures not seen radiographically
Isolated greater trochanter #
Isolated lesser trochanter #
Subtrochanteric fracture
Proximal Femur & Hip
Practice
Intertrochanteric fracture 2° to mets from prostate CA
Pipkin III femoral head fracture and posterior dislocation
Shoulder
AC separation
Clavicle fracture
Scapula fracture
Shoulder dislocation
Shoulder: Anatomy
3 bones:
 Clavicle
 Humerus
 Scapula
3 joints:
 Acromioclavicular
 Glenohumeral
 Sternoclavicular
1 articulation:
 Scapulothoracic
Shoulder: Anatomy
Shoulder: Anatomy
Shoulder: Images
True AP
 Should see no overlap of humerus over the
glenoid
Lateral (transcapular)
 Scapula looks like a ‘Y’)
Axillary
 Best “true lateral” view of the shoulder
AC view
 100° abduction
Shoulder: Images
Internal rotation
External rotation
More useful for soft-tissue
evaluation
Normal True AP of the Shoulder
Normal lateral film of the shoulder
Normal axillary film of the shoulder
AC Separation: Classification
 Type I
 Sprain of the AC joint
 CC distance maintained (N = 1113mm)
 Type II




AC ligaments disrupted
Joint space widened
CC distance maintained
Clavicle rides upward (<50% its width)
AC Separation: Classification
 Type III (and IV, V, VI)
 Complete disruption of AC and
coracoclavicular ligaments as well
as muscle attachements
 Joint space widened
 CC space is increased
(5mm difference from uninjured
side)
 Clavicle is displaced
Type III AC separation – AC view (100° Abduction)
Clavicle Fracture
Classified anatomically:
1.
Medial third (5%) – direct blow to the anterior chest
2.
Middle third (80%) – direct force to lateral aspect of
shoulder
3.
Lateral third (15%) – direct blow to the top of
shoulder
I.
Lateral to the coracoclavicular lig. (stable)
II.
Medial to the coracoclavicular lig. (tend to displace)
III. Involves the articular surface
Fracture of the middle third of the clavicle
Comminuted fracture of the middle third of the clavicle
Distal third clavicle fracture – type II
Scapula Fracture
Classified Anatomically:
I.
Acromion process, scapular spine or coracoid process
II.
Scapular neck involved
III.
Intra-articular fractures of the glenoid fossa
IV.
Scapular body involved (most common)
Type I scapular fracture (coracoid fracture)
Type III scapular fracture
Comminuted, type III scapular fracture
Shoulder: Dislocation
Classification
Anterior (95-97%)
 Subcoracoid (most common)
 Subglenoid
(1/3 associated with # greater tuberosity, or # glenoid rim)
 Subclavicular
 Intrathoracic
 Also important to note primary vs. recurrent
Anterior dislocation - subcoracoid
Shoulder: Dislocation
Classification – cont’d
Posterior
 Subacromial (98% of posterior dislocations)
 Subglenoid
 Subspinous
Inferior (Luxatio Erecta) - rare
superior - rare
Shoulder: Dislocation
Signs of posterior shoulder dislocation:
 ↑distance from anterior glenoid rim and humeral head
 “rim” sign
 Humeral head internally rotated
 “Light bulb” or “drum stick” sign
 True AP shows humeral/glenoid overlap
 Impaction # of the anteromedial humeral head
 “reverse Hill-Sachs deformity”  “Trough sign”
Posterior dislocation
Arrow = impaction # of anteromedial humeral head
Posterior dislocation
Note the humeral head roatation
Posterior dislocation – lateral view
Posterior dislocation – axillary view
Shoulder: Dislocation
Associated fractures:
1. Compression # of the posterolateral aspect of the humeral
head
 “Hill-Sachs deformity”
 11-50% of anterior dislocations
2. Anterior glenoid rim fracture
 “Bankart’s fracture”
 ~5% of cases
3. Avulsion fracture of the greater tuberosity
 ~10-15% of cases
Anterior dislocation
Arrow = # of the posterolateral aspect of humerus
Post-reduction film
Avulsion # of the greater tuberosity
Shoulder
Practice
Clavicle fracture – distal third – type II
Scapula fracture – type III
AC separation - grade I
Anterior shoulder dislocation
Posterior dislocation (False AP – note overlap)