x-rays: pelvis, hip & shoulder feb. 22, 2006 j. huffman, pgy-1 thanks to dr. j. lord also thanks...
TRANSCRIPT
X-rays:Pelvis, Hip & Shoulder
Feb. 22, 2006J. Huffman, PGY-1
Thanks to Dr. J. LordAlso 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 epidemiologyNo managementNo associated injuries (i.e. vascular injury with
pelvic #)
Outline
1. Pelvisa) Anatomyb) Viewsc) Classification of
fracturesd) Practice
2. Hipa) Anatomyb) Views c) Fracturesd) Dislocationse) Practice
3. Shouldera) Anatomyb) Viewsc) Dislocationsd) Fracturese) 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 ligamentSacrotuberous ligamentPelvic diaphragm
Pelvis: Anatomy
Very strong posterior ligaments Disruption of these is the cause of mechanical
instabilityArteries 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 injuriesPelvic films are NOT necessary in pts with normal physical
exam, GCS >13, no distracting injury and not intoxicatedAt least one study shows clinical exam reliable in EtOH
Gonzalez et al. J Am Coll Surg. 2002; 194: 121-5
CT scansEvaluates extent of posterior injury betterSuperior imaging of sacrum and acetabulumMore 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:
AdvantagesComprehensivePredicts need for operative intervention
DisadvantagesDoes NOT predict morbidity or mortality
Young Classification System: Advantages
Based on mechanism of injury predicts ass’d injuryEstimates mortality
DisadvantagesExcludes 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 injuryLC I – sacral compression
on side of impactLC II – iliac wing # on
side of impactLC 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 FracturesAPC 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
Posterior Column #
Focus on the acetabular fractures.
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
EtiologyAdults: high energy mechanism (MVA)Elderly, prosthetic joints, kids < 6yo: minor mech
Types:Posterior >> anterior > central (> inferior)
Orthopedic emergencies:Urgent reduction after ABC’s / stabilizationSignificant neurovascular complicationsOften multiple associated injuriesMandate CT post-reduction
Hip: Dislocation imaging
Plain Films: ant vs. post dislocationsFemoral head size
Posterior dislocation femoral head smallerLesser 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 dislocationPipkin classification
Femoral neck fracture:Can be subtle (check lines, ‘S’)Describe as nondisplaced (15-20%) vs displaced
Intertrochanteric fracture:High energy or weak boneClassify 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 iliopsoasOutpt management
Subtrochanteric fracture:#’s b/w lesser trochanter & point 5 cm distalCommon site for pathologic fracturesVague 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 separationClavicle fractureScapula fractureShoulder dislocation
Shoulder: Anatomy
3 bones:ClavicleHumerusScapula
3 joints:AcromioclavicularGlenohumeralSternoclavicular
1 articulation:Scapulothoracic
Shoulder: Anatomy
Shoulder: Anatomy
Shoulder: Images
True APShould see no overlap of humerus over the
glenoid
Lateral (transcapular)Scapula looks like a ‘Y’)
AxillaryBest “true lateral” view of the shoulder
AC view100° abduction
Shoulder: Images
Internal rotation
External rotationMore 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 = 11-
13mm)
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
PosteriorSubacromial (98% of posterior dislocations)SubglenoidSubspinous
Inferior (Luxatio Erecta) - raresuperior - 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 dislocationArrow = impaction # of anteromedial humeral head
Posterior dislocationNote 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 dislocationArrow = # of the posterolateral aspect of humerus
Post-reduction filmAvulsion # 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)