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38 Cards in this Set
- Front
- Back
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MCL and LCL
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taut in extension
lax in flexion, allowing tibiofemoral rot, ABD, ADD |
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ACL - Anteromedial
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CKC FL: taut, max at 70 deg
CKC EXT: slight lax OKC FL: taut OKC EXT: lax |
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ACL - Posterolateral
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CKC FL: lax
CKC EXT: taut OKC FL: lax OKC EXT: taut as full EXT reached |
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PCL - Anteromedial
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CKC FL: taut, max at 80-90 deg
CKC EXT: lax OKC FL: taut OKC EXT: lax |
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PCL - Posterolateral
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CKC FL: lax
CKC EXT: taut OKC FL: lax OKC EXT: taut |
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ACL motion restriction
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limits medial rotation of tibia winding around PCL and lateral rotation of tibia by stretching over lateral femoral condyle
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PCL motion restriction
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limits tibial rotation
resists valgus and varus stress to knee |
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ACL anteromedial injury
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damage may occur with knee FL and medial or lateral rotation
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ACL posterolateral injury
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damage may occur with knee hyperEXT
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PCL anteromedial injury
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damage may occur with knee FL
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PCL posterolateral injury
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damage may occur with knee EXT
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Knee motion required for ADL
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115-120 deg Fl
-5 to -10 deg EXT |
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Arthrokinematics of CKC knee FL
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0-25 deg: ant rot of femoral condyles (post roll of femur)
25-140: ant rot of femoral condyles + ant glide (post roll of femur) |
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Components of anterior femoral glide during CKC knee FL
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ACL tension
condyles slide on post. menisci post. menisci move posteriorly |
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Arthrokinematics of CKC knee EXT
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140-115 deg: post rotation of femoral condyles (ant roll of femur)
115-0 deg: post rot and post glide of femoral condyles (ant roll of femur) |
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Components of posterior glide during CKC knee EXT
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PCL tension
menisci move anteriorly |
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Arthrokinematics of OKC knee FL
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tibia rotates and glides posteriorly
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Arthrokinematics of OKC knee EXT
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tibia rotates and glides anteriorly
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Purpose of the Screw Home Mechanism
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maximum bilateral surface area contact between femoral and tibial condyles
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Screw Home Mechanism
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CKC EXT: femoral internal rotation occurs as result of longer medial femoral condyle
OKC EXT: tibial external rotation occurs as result of longer medial femoral condyle |
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Unlocking the Screw Home Mechanism
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the popliteus contracts to:
-ER the femur in CKC FL -IR the tibia in OKC FL |
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Helfet Test
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pt seated with lower leg hanging
PT marks med/lat/midline of patella and tibial tuberosity PT observes tibial tuberosity position as pt EXT knee NORMAL: tib tub moves lat during EXT |
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Knee EXT Muscles
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rectus femoris
vastus lateralis vastus intermedius vastus medialis |
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Knee FL Muscles
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biceps femoris
semitendinosus semimembranosus gastroc plantaris popliteus |
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Tibial ER Muscles
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biceps femoris
TFL |
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Tibial IR Muscles
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semitendinosus
semimembranosus popliteus gracilis sartorius |
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Genu Valgum
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MCL, jt capsule tense = med knee pain
increase contact of lat femoral & tibial condyles = lat knee pain, increased lat DJD |
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Genu Varum
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LCL, lateral jt. capsule strain = lateral knee pain
increased contact of med femoral and tibial condyles = med knee pain and increased risk of DJD |
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High compression force at knee during HEEL STRIKE
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bodywt + eccentric hamstring contraction to control extension and stabilize knee
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High compression force at knee during FOOT FLAT
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body wt + eccentric contraction of quads controlling knee FL and resist buckling
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HIGHEST compression force at knee during HEEL OFF
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bodywt + compaction of knee occuring with concentric gastroc contraction which is PF the ankle
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Role of Menisci
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inc. tibial surface area to:
-inc force distribution -dec unit force on condyles -inc jt. stabilization |
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Patellar motion during Knee FL:
0-20 deg |
-tibia IR
-dec lateral pull on patella -patella -> intercondylar groove -contact: inferior pole |
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Patellar motion during Knee FL
20-90 deg |
-patella follows intercondylar groove
-contact: lat&med facets -70-90 deg: quad tendon becomes wt bearing structure dec. PF jt. compressive force |
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Patellar motion during Knee FL
90-135 deg |
- >90 deg lateral movement and medial tilting
- odd facet contacts medial femoral condyle at 135 deg |
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Compression forces at the patellofemoral joint
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-result of quad and patellar ligament tension
- 0 to 5 deg: near 0 force - 45 and up: significant increase in quad and patellar ligament force, greatest above 90 deg |
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Quadriceps Torques
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level walking = .5 x bwt
stair climb = 3-4 x bwt squats = 7-8 x bwt |
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Factors of abnormal patellar motion
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-tight IT band
-VMO weakness -rec fem tightness -abnormal Q-angle -patellar ligament length abnormality |
