knee Flashcards
ACL tibial insertion?
between intercondylar eminences
ACL femoral attachment?
posteroMEDIAL ASPECT of LATERAL CONDYLE
TWO BUNDLES of ACL? (clue: named based on tibial insertion)
anteromedial and posterolateral bundles
ACL bundle tight in FLEXION, ANTERIOR restraint, tested with lachman/ANTERIOR drawer?
ANTEROMEDIAL bundle
ACL bundle tight in EXTENSION, a ROTATORY restraint, tested with pivot shift?
POSTEROLATERAL bundle
blood supply of cruciate ligaments?
middle geniculate artery, fat pad
PCL femoral attachment?
anteroLATERAL ASPECT of MEDIAL CONDYLE
PCL tibial insertion?
tibial sulcus BELOW ARTICULAR SURFACE
TWO BUNDLES of PCL?
anterolateral and posteromedial
MCL biomechanics?
anterior fibers tight @ <90degrees
posterior fibers tight @ 180degrees
most anterior structure on proximal fibula?
LCL
LCL biomechanics?
tight in extension, lax in flexion
posteroMEDIAL corner function?
ROTARY stability
posteroLATERAL corner function?
primary stabilizer of EXTERNAL TIBIAL ROTATION
vascularized parts of menisci?
peripheral 20-30% MEDIAL meniscus
peripheral 10-25% LATERAL meniscus
blood supply of menisci?
medial and lateral genicular arteries
shapes of menisci?
medial:C-shaped, lateral:circular
function of menisci?
1) deepen articular surfaces
2) stability
3) lubrication
4) nutrition
attachment between menisci?
transverse (intermeniscal) ligament
peripheral attachment of menisci?
coronary ligaments
MORE MOBILE meniscus?
LATERAL meniscus (fewer attachments - 2x more mobile)
more commonly torn meniscus?
MEDIAL meniscus ~3x more
more commonly torn meniscus WITH ACL tear?
LATERAL meniscus
meniscal tears with highest healing potential?
tears in PERIPHERAL 3RD of meniscus
“screw home mechanism”?
medial tibial plateau rotates externally in full extension
function of medial patellofemoral ligament?
> 50% restraint to lateral subluxation
stronger graft: patellar tendon vs quadrupled hamstring?
quadrupled hamstring BUT dependent on graft fixation
history of pain after SITTING/CLIMBING?
PATELLOFEMORAL injury
history of LOCKING/SQUATTING pain?
MENISCAL tear
history of NONCONTACT injury with ‘POPPING’?
ACL tear or patellar dislocation
history of ACUTE SWELLING?
ACL or meniscal tear
history of hyperextension, varus angulation, tibial external rotation?
POSTEROLATERAL CORNER injury
SIGNIFICANT DIFFERENCE of knee laxity?
> 3MM between left and right knees
MOST SENSITIVE imaging view for EARLY ARTHROSIS?
WEIGHT-BEARING 45-degree POSTEROANTERIOR view
significance of joint line tenderness?
meniscal tear
components of Q-angle?
ASIS-patella-tibial tubercle
indication of partial meniscectomy?
complex, degenerative, central/radial tears
indication of meniscal repair?
peripheral longitudinal tears, young patients
gold standard of meniscal repair?
vertical mattress sutures
associated with chronic ACL deficiency?
higher incidence of complex meniscal tears
graft of choice for early return to sports activity?
bone-patella-tendon-bone autograft (faster incorporation)
disadvantage of BPTB autograft?
higher incidence of arthritis 5-7yrs after reconstruction
why is primary ACL repair NOT recommended?
myofibroblasts coat end of ACL stumps, making healing impossible
STANDARD IMAGING for evaluation and grading of PCL injuries?
STRESS RADIOGRAPHS
MRI only confirmatory
rehab focus for ACL/PCL injuries?
ACL:hamstrings, PCL:quadriceps
J sign?
lateral deviation of patella in extension
most sensitive test for ACL injury?
LACHMAN (pull tibia @ 30deg flexion)
how arthrocentesis/intraarticular knee injection is done?
extended knee, lateral entry point @ mid-upper patella