Ankle Sprain
Bryce Bederka, MD
August 17, 2006
Syndesmosis Injury
Ankle Sprain
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Ankle sprains are the most common athletic injury (23-25%)
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Inversion sprains injuring the ATFL is the most common mechanism
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Generally resolve with conservative care (RICE)
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Many varieties and associated injuries
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Incorrect or delayed diagnoses
Outcomes
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1998 West Point study
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23% of all injuries in cadets were ankle sprains (15% of ankle
injuries were syndesmotic sprains)
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All were back to activity by 6 months
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40% reported residual pain or loss of function
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Most significant predictor of poor outcome was syndesmotic injury
of any grade
Anatomy
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3 Bones
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6 Ligaments
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9 or 10 tendons
Anatomy
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3 Bones
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Tibia
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Fibula
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Talus
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Talocrural joint
Anatomy
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Lateral Ligaments
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Anterior talofibular ligament
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Posterior talofibular ligament
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Calcaneofibular ligament
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Anterior and Posterior
tibiofibular ligament
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Interosseous membrane
Anatomy
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Medial Ligament
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Deltoid ligament
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Superficial
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Tibionavicular
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Tibiocalcaneal
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Tibiospring
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Superficial tibiotalar
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Deep
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Anterior tibiotalar
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Posterior tibiotalar
Motion
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Hinge with some slop
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Talus wider anteriorly
lStable in dorsiflexion
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Axis is oblique
lDorsiflexion produces external
rotation
lPlantarflexion produces
internal rotation
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Normal range of motion
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15-25 dorsiflexion
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40-55 plantarflexion
Physical Exam
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Starts with a good history
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Elucidate the mechanism of injury
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Skin
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Swelling and ecchymoses
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Active ROM/Passive ROM
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Palpate for tenderness
Physical Exam
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Anterior Drawer
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Tests for ATFL injury
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False negatives in acute
setting/guarding
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Talar Tilt
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Tests ATFL and CFL (varus) and
Deltoid (valgus)
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Squeeze Test
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Midshaft squeeze elicits pain at
syndesmosis
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External Rotation Stress Test
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Externally rotated foot elicits
pain at syndesmosis
Syndesmosis Exam
Ottawa Ankle Rules
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X-rays are only required if there
is any pain in the malleolar or midfoot area, and any one of the following:
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Bone tenderness along the distal
6cm of the posterior edge of the tibia or tip of the medial malleolus
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Bone tenderness along the distal
6cm of the posterior edge of the fibula or tip of the lateral malleolus
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Bone tenderness at the base of the
fifth metatarsal (for foot injuries).
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Bone tenderness at the navicular
bone (for foot injuries).
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An inability to bear weight both
immediately and in the emergency department for four steps.
Imaging
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In acute lateral ankle sprains, plain films are often unremarkable
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In chronic or recurrent sprains, pathologic findings may exist
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With syndesmotic injuries may have characteristic findings
Imaging
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Subfibular ossicle
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Avulsion Fx
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Chronic ATFL injury
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Os Fibulare
Imaging
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Talar tilt
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Wide range of normal
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4-20 degrees
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Naval cadets had >10 degree
difference in symptomatic ankles
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Need to compare both sides with a
similar load, no absolute criteria
Imaging
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AP Stress Test
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>3mm considered abnormal
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Compare sides
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Evaluates for ATFL function
Imaging
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External rotation stress test
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AP or lateral
Imaging
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Medial clear space
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<4mm is normal
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Tibiofibular clear space
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<6mm is normal
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Overlap
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1mm on mortise
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6mm on AP
Imaging
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MRI yields a wealth of information regarding bony, cartilagenous,
ligamentous, tendon, and soft tissue pathology
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Not a first line test!
Grading of Injury
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Grade I
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Pain, no laxity
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Grade II
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Pain, increased laxity with good endpoint
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Grade III
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Pain, unstable ankle
Classification
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Scranton (AAOS)
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A. Acute (0-6 wks)
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I: partial AITFL / stable
(- stress tests, normal xray)
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II: complete AITFL/ partial IM/ stable or unstable
(+ stress tests, normal xray)
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III: complete AITFL/deltoid/ grossly unstable
(+ xray)
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B. Subacute (6 wk-3 mos)
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C. Chronic (> 3 mos)
Treatment
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Grade I
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Symptomatic RICE, early mobilization
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Grade II
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Symptomatic RICE, early mobilization
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Grade III
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Depends
Treatment
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Hopkinson, 1990
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West Point cadets
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G I or II syndesmosis sprains took 55 days to return to activity
vs 28 days for G III lateral ankle sprains
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Boytim, 1991
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Football players
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Syndesmotic injuries missed up to 6 weeks, and did not practice
for 6 practices
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Lateral sprains missed 1.1 practices
Treatment
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Grade III Lateral
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Early mobilization
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Cast immobilization
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Surgical stabilization
Treatment
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Grade III Medial
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Surgery is rarely necessary
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Cast immobilization
Treatment
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Grade III Syndesmosis
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Nondisplaced may be treated with cast immobilization and NWB
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Displacement or late diagnosis more likely to do poorly without
anatomic surgical reduction (<2mm compared to contralateral side)
Treatment
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Rigid fixation
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Anatomic reduction
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Edwards and DeLee, 1984
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Six patients treated operatively with syndesmotic screw
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4 Good, 2 Fair
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Miller, 1995
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4 football players with high ankle sprain
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All fixed with syndesmotic screw
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1 Excellent, 3 Good at final f/u
Treatment
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Cox, 2005
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PLLA/PGA screw vs stainless steel screw
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Tested to 1000 cycles
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Both had equal loosening and failure torque
Treatment
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Miller, 1999
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Looked at novel suture configuration for flexible syndesmotic
repair in a cadaver model
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Was equivalent to 3.5mm tricortical screw with respect to maximal
load to failure and displacement
Treatment
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Thornes, 2003
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Compared suture-endobutton technique to 4.5mm screw through 4
cortices in a cadaver
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No significant difference in strength or failure
Treatment
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Thornes, 2005
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Clinical study of
suture-endobutton vs screw fixation
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AOFAS score higher for
suture-endobutton vs screw fixation at 3 months and 1 year (93 vs 83)
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No loss of reduction, no second
operation
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Weight bearing initiated 2 weeks
earlier (4 vs 6 weeks)
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More rapid return to work (2.8 vs
4.6 months)
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93% G/E with suture repair vs 69%
with screw at 12 months
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All poor outcomes (3) were in
screw group
TIGHTROPE
TightRope™ Syndesmosis
Repair Kit
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Kit Contents:
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3.5 x 10 mm Oblong Button
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6.5 mm Diameter Button
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Drill Bit (solid or cannulated)
Other TightRope™ Features
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One size fits all
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No additional
instruments
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Titanium or Stainless
Steel
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Easy removal, if
necessary
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Better grip
(snow-shoe) on osteoporotic bone*
Testing: Cycles to Failure
TightRope Technique
TightRope Technique
TightRope Technique
TightRope Update
TightRope Technique
TightRope Technique
TightRope Technique
Post fixation with tightrope