ACL Flashcards
Functions of ACL
limits anterior translation of the tibia on the femur
contributes to rotational stability
Highest prevalence in sports for ACL injuries
basketball
soccer
alpine skiing
lacrosse
football
Mechanism of injury for ACL
MOI
70% are non-contact injuries
tibia translates anteriorly while knee is in slight flexion and valgus
Patient Reports with ACL injury
pop or tearing sensation
pain
immediate swelling = hemarthrosis
sense of instability
lack of full knee extension at midstance
Clinical Exam of ACL injury
joint effusion
decreased active and passive ROM
decreased force production quads
decreased extension at midstance
partial weight bearing or limp
Diagnosis of acl injury
feeling of soft end feel when it should be firm
MRI is the gold standard
manual gold standards = lachman (78%) and pivot shift (89%)
Associated injuries with ACL injury
meniscal tears
multi-ligament tears
osteochondral defects
bone marrow edema
tendon tears
arterial tears
nerve injury
dislocation
ACL Reconstruction
Autografts
Allografts
Autografts
own tissue
patellar tendon (central 1/3)
hamstring
Allografts
cadaver grafts
taken from achilles, posterior tib, anterior tib
Single Bundle ACL
gold standard, has the best results
Femoral tunnel placement
frontal plane malpositioning
Anterior tunnel misplacement
knee is tight in flexion and loose in extension
Posterior misplacement
knee is lax in flexion and tight in extension
Psychosocial Complications of ACL
surgery/rehab
loss of sports season
loss of scholarship funding
lowered academic performance
kinesiophobia
disability
Long-Term Complications of ACL
Post-traumatic osteoarthritis following ACL injury is 87%
Possible causes:
inflammatory cytokine
osteochondral defects
osteochondral lesions
loss of meniscus cartilage
persistent instability
ACL strain is greatest between
10° to 30° of knee flexion
ACL strain gradually decreases between
30° to 60° of knee flexion
ACL strain is insignificant at
knee flexion angles greater than 60°
Day 1 intervention for ACL
get swelling under control, restore extension
check ankle dorsiflexion and begin stretching gastrocsoleus complex. practice hip hinging
Quads Contraction
loading the ACL
anteriorly directed force on the proximal tibia, most notably at 0° to 60° flexion
Hamstring contraction
unloading the ACL
posteriorly directed force on the proximal end of the tibia
Squatting with heels off the ground
over 3 times more ACL loading compared to squatting with heels on the ground
at greater knee flexion angles, heels lift off, knees go beyond toes, shear force on ACL increases
Minimize load on ACL
lean trunk forward 30 to 40° from vertical during squats at knee angles 15-90° using hip flexion (vs lumbar flexion)
leaning trunk forward helps you to optimally recruit hamstrings
Single vs double leg squats
significantly greater ACL load during single leg squat
knee moves forward an average of 10 cm beyond the toes compared to double leg squats
Sagittal plane motion of trunk can influence the moments at hip and knee
landing with trunk forward increases the moment at the hip while decreasing moment at knee
landing with trunk erect increases the moment at knee while decreasing moment at hip
