Knee

Question 1

2 Articulations

Answer 1

Tibiofemoral joint
-distal femur and prox tibia
-double condyloid
-flx/ext, IR/ER, ABd/ADD

Patellofemoral joint
-distal femur and patella

Question 2

Tibiofemoral Joint

Answer 2

-medial tibial more anterior and longer
-separated by intercondylar notch
weightbearing through center of knee

Genu valgum: <175
Genu carum: >185

Question 3

Meniscus

Answer 3

Medial: c shaped, restricted, more attachments

Lateral: circular, more mmt, popliteus, covers more surface

-Post deformation with flx
-ant deformation with ext

Nutrition:
-outer more vascularized
-inner gets nutrition from difussion

Question 4

Joint Capsule

Answer 4

-close packed: full extension

-Posterior boarder: condyles, intercondylar notch

-Anterior boarder: quad tendon, patella, patellar lig, extensor mechanism

-Extensor Mechanism: medial and lateral retinaculum

-Synovial Layer

-Fibrous Layer

Question 5

Synovial Layer

Answer 5

Extrasynovia but intracapsular: ACL and PCl, fat pads
-Bursae: invaginatons of synovium

Plica: folds of membrane, loose tissue
-not in everyone
-plica syndrome (inflammed)
-medial less common, source of pain

Question 6

Fibrous Layer

Answer 6

-Medial patellofemoral lig: thickest band in med retinaculum, stabilized patella in femoral sulcus, blends with MCL

-Lateral patellofemoral lig: ITTB to lateral patella

Question 7

MCL

Answer 7

-medial femoral condyle to medial tibia and med meniscus
-resist valgus and tibial ER

Question 8

LCL

Answer 8

-lateral femoral epicondyle to fibular head with bicep fem tendon
-resistt varus and ER

Question 9

ACL

Answer 9

-posteromedial aspect of lat femoral condyle to anterolateral aspect of medial intercondylar tibial notch
-taugh in CC flx
-anteromedial (taught in >15 flx) and posterolateral (taught in ext) bundles
-ACL retrains quads anterior shear on tibia

Question 10

ACL Injury

Answer 10

-coconttraction ofo hamstrings and quads allow hammies to counter anterior translation from quads
-soleus can resist ant translation of tibia in closed chain

Question 11

PCL

Answer 11

-anterolateral aspect of med femoral condyle to posterior aspect of intercondylar tibial notch
-taut in CC ext
-bigger than ACL
-posteromedial (taught in ext) and anterolateral (taught in 80 flx) bundles
-restains posterior translation of tibia (knee flexed too)

Question 12

Posterior Capsule

Answer 12

-reinforced by politeus, semimembranosus and LCL

-Oblique popliteal lig: expansion of semimembranosus

-Posterior Oblique lig: taught in ext, reisist varus/valgus

-Arcuate lig: taught in ext, reisist varus/valgus

Question 13

ITB

Answer 13

-extension of TFL and glute max to gerdy’s tub
-inc lat stability
-compresses or rolls during flx/ext

Question 14

Joint Kinematics

Answer 14

CC Flx/ext: femur rolls post and glides ant (ext opp), convex on concave

OC Flx/Ext: Tibia rolls psot and glides post (ext opp), concave on convex

Normal Range:
5-0-140
Walking: 60-70 flx
Stairs: 80
Sit to stand: 90
IR in 90 flx: 15
ER in 90 flx: 20
ADD/ABD in Ext: 8 deg
ADD/ABD in flx: 13-20deg

Question 15

Knee Extension

Answer 15

-can be limitted by DF

Question 16

Knee Flexion

Answer 16

-can be limited by passive insufficiancy of hamstring

Question 17

Coupled Motions

Answer 17

-Flexion with varus
-extension with valgus
-Terminal knee ext with ER (OC, screw home mechanism)
-Flex from full ext OC IR tibia
-FLex from full Ext CC ER of femur

Question 18

Knee Flexors

Answer 18

Hamstrings:
-SM/ST IR
-BF ER

Sartorius: flx and IR

Gracilis: flx and IR

Popliteus: flx and IR

Gastroc and Soleus: Valgus/varus

Question 19

Knee Extensors

Answer 19

Quads: VL and VM posterior compressive force
Quad tendon
Patellar tendon
Glute max: in WB
Soleus: in WB

Question 20

Patella on Quad

Answer 20

-patella and femoral condyles lengthen MA of quads and increases torque (anatomical pulley)
-max MA at 45-60 flx
-MA decreases in full ext

Question 21

Quads in Stance

Answer 21

-2x as strong as hamstrings
-Soleus and glute max assists with knee EXT

OC: quads generate more torque as knee aproches ext (concentric) (les ant tib shear)

CC: quads generated more force to control increasing torque (eccentric) (more ant tib shear)

Question 22

Knee Stabilizers

Answer 22

Ant Tib translation:
-ACL, ITB, Hammies, soleus, glute max

Post tib translation: PCL, quads, popliteus, gastroc

Limit Valgus: MCL, ACL, PCL, arcuate, medial muscles

Limit Varus: LCL, ITB, ACL, PCL, arcuate, Lat muscles

IR TIbia: ACL, PCL, PM capsule

ER tibia: PL capsule, MCL, LCL, medial muscles

Question 23

Patella Alta

Answer 23

-longer and higher on femur
-unstable

Question 24

Patella Baja

Answer 24

-shorter and lower on femur

Question 25

Motions on Patella

Answer 25

-Translates and rotates on femoral condyles
-lateral shift in ext (less compression in ext)
-medial shift in flx (most compression in flx)

-inferior position with extension and early flx
-superior position 90deg
-lateral position >90deg

Question 26

Walking Stresses

Answer 26

25-50% BW

Question 27

Running Stresses

Answer 27

5-6x BW

Question 28

Q Angle

Answer 28

-assess resultant pull
-measured in EXT
-10-15deg norm, >20 mal alignment (genu valgum)
-women > men