Y5 - Knee: Anterior cruciate ligament (ACL) tear Flashcards
what is the function of the ACL
prevents anterior tibial displacement
where does the ACL originate
the posteromedial aspect of the intercondylar notch on the lateral femoral condyle
where do the proximal fibres of the ACL run
along the medial wall of the lateral femoral condyle
what are the two bundles of the ACL
anteromedial
posterolateral
where does the ACL attach
onto the articular surface of the tibia, medial to the attachment of the anterior horn of the lateral meniscus
what does the ACL blend into
the anterior horn of the lateral meniscus
what is the common mechanism of injury for ACL tear
sudden change in direction causing the knee to rotate inwards
epi
more common in women than men due to anatomical differences in ACL
why are ACL tears more common in women than men
the synovial joint through which the ACL passes is smaller in women than in men causing greater susceptibility to damage due to higher levels of strain
also women use their quads>hamstrings which causes additional strain
define
a ligament which runs diagonally in the middle of the knee from the posterior femur to the anterior tibia
function of ACL
prevents anterior tibia displacement and provides rotational stability
what are the different strains for an ACL injury
Grade 1 - ACL has been stretched, knee is still stable
Grade 2 - ACL has been stretched and is now loose (partial tear)
Grade 3 - ACL has been completely torn
aetiology of ACL injury
changing direction rapidly
stopping suddenly
landing from a jump
direct contact or collision
epi
more common in women
signs and symptoms
a popping sound pain & swelling haemarthrosis loss of range of motion tenderness
who is avulsion with ACL injury most common in
children
what is the most accurate manoeuvre for detecting an acute ACL tear
the Lachmans test
what is the most accurate manoeuvre for detecting a chronic ACL tear
pivot shift test
what is segonds fracture
a small capsular avulsion off the lateral aspect of the proximal tibia
investigations
XRay - usually negative, may show segonds sign
MRI
where may there by tenderness
at the lateral femoral condyle, the lateral tibial plateau
management
depends on lifestyle, sedentary vs intense dynamic demands
what different types of surgery are performed for ACL repairs
bone-patellar tendon-bone autograft
hamstring tendon grafts
complications
bone bruising
medial collateral ligament injury
what is the Unhappy Triad of O’Donoghu
a torn ACL
a torn MCL
a torn medial meniscus
prognosis
good mechanical reconstruction
however few sportsman return, suggesting psychological factors
