Synopsis
Imaging Technique
- Elbow
in extension, arm at side, forearm supination
- Small
surface coil: (flex or 2 part phased
array surface coil)
- Avoid
arm “over the head” in extremity coil: places traction on plexus; accentuates
motion
- Postop: watch RBW keep 244-300 Hz/pixel with IES
5-6msec
- Coronal
FSE slice <2mm with NO GAP!
- Coronal
IR or Dixon (avoid frequency selective fat sat or GRE)
- Coronal/
Sagittal/ Axial FSE with moderate TE 28-34msec/ TR>3000
- 3DMSI technique for
“heavy metal”
Medial Collateral Ligament: anatomy
and mechanics
- Anterior
bundle: composed of anterior and posterior bands
-
Anterior band is primary restraint to
valgus load
-Injury most significant @ 60º/90º flexion
-Taut in elbow extension
- Posterior band is secondary restraint
- Injury most severe @ 120º flexion
-
Posterior
bundle
-
Contributes little to primary stability
- Best seen in elbow flexion
- Arises from medial epicondyle and
inserts broadly into olecranon
MRI of the Throwing Elbow
- Valgus
overload during acceleration stage of arm swing
- MCL
tears: plastic deformation with superimposed partial thickness tears
-
Assess degree of remodeling
-
Flexor/pronator
tendinosis and/or tear
- Valgus
extension overload
- posteromedial impingement
-
Cartilage
status
-
trochlea, olecranon (high contact
pressures)
- RC joint (end stage)
-
Ulnar
neuropathy
Posteromedial Impingement Valgus Extension Overload
- Concentration
of contact stresses between medial olecranon & medial humeral trochlea
- MCL
injury produces microinstability
- Windshield
wiper effect
- Increased
chondral surface pressure
- Cartilage
wear over posterior trochlea and olecranon
Post operative elbow in throwing athletes
- Use
high resolution scanning (1.5T or 3T; coronal slice ≤ 1.8mm)
- Fat
suppression is your bone scan
-
Acute on chronic tear: extracapsular
edema
-
Filter
the small stuff!
- Use
sequences to accentuate gray scale in remodeled collagen
-
Chronic plastic deformation is more
common than acute tear
-
Cartilage-sensitive
imaging always essential
MCL Reconstruction
- Palmaris
longus graft utilized to augment (not replace) deficient MCL
-These look horrible on their best day!
-
Graft
is fixated via osseous tunnels or “docking technique”
- +/-
ulnar nerve transposition
- Choice
of pulse sequence essential
-
Avoid GRE and
frequency selective fat suppression
Stress Fractures
- Commonly co-exist with other pathology
in throwing elbow
- Signs of nonunion: sclerosis ( awareness
of physeal closure, particularly olecranon), progressive bone marrow edema
-
Assessing healing
through hardware
Fracture dislocations
- In
adults, 80+% associated with decrease ROM and joint contracture (loss of
extension and loss of >20 deg flexion)
- Chondrolysis
severe and under-reported due to reliance on radiographs
- 3
plane cartilage sensitive imaging; need to see cartilage around instrumentation
(3DMSI)
- Repair: microfracture, OC transplantation (OATS vs
allograft)
-
Application of 3D
modeling for repair techniques
Tendinopathy and Repair
- Assess
for re-tear, muscle quality, fx through enthesopathic spur, bursitis
- Mode
of fixation: screw purchase? bioabsorbable?
Osteolysis? Synovitis?
Acknowledgements
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