SPORT INJURIES AND SPORT INJURIES AND BIOMECHANICS BIOMECHANICS ACL RUPTURE
Jan 11, 2016
SPORT INJURIES AND SPORT INJURIES AND BIOMECHANICSBIOMECHANICS
ACL RUPTURE
ANATOMYANATOMY
Intra capsular knee joint structureLength 38mm( 25 to 41mm)Width 10mm (7 to 12mm)Made up multiple collagen fibersSurrounded by synovial membrane
envelope
ANATOMYANATOMY
Femoral proximal attachment :postero- lateral corner of inter condylar notch
Tibial distal attachment : front and lateral of anterior tibial spine
Two bands: small anteromedial and a larger posterolateral portion
BIOMECHANICSBIOMECHANICS
Posterolateral bulky portion is tight in extension
Anteromedial bundle is tight in flexionUltimate tensile load :2160 +/- 157 NApprox 85% resistance to anterior tibial
displasment
Maximum laxity in 30 deg Maximum laxity in 30 deg flexionflexion
Biomechanical characteristicsBiomechanical characteristics
ACL does not remain an isometric or constant length structure
Unsectioned ACL :2-5mm anterior translation at full extension 5-8 mm at 30 deg flexion by application 100N anterior force
ACL ruptureACL rupture
Common and severe injury particularly in compact sports as rugby
Usual mechanism of injury knee hyperextension or external rotation in flexion
AP instabilityAP instability
7-9 mm of increased translation (100N anterior force)
Supporting structures in ACL rupture: iliotibial band 24% medial capsule 22% lateral capsule 20% MCL 16% LCL 12%
Quadriceps and hamstrings in a certain degree alsoBaratta et al 1988
Moment vs. time. Examples of quadriceps avoidanceDevita et all 1998 Timony et all 1993
Matt Gaudet 2000Matt Gaudet 2000
1
2
0
50
100
150
200
250
300
An
gu
lar
imp
uls
e (N
*m*s
)
subjects
normal
injured
Load deformation curveLoad deformation curve
Deformation
Load
Elastic Region
Plastic Region
Yield Point Ultimate
Failure
Point
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