Knee Complex Flashcards
Knee
One of the most commonly injured areas of the body
What has a heavy influence on the knee?
The hip and ankle
What controls stability and mobility of the knee?
Boney, ligamentous, chondral, and muscular anatomy
3 Joint Articulations of the KNEE
Tibiofemoral
Patellofemoral
Proximal Tibiofibular
Boney Anatomy of the Knee
Femur
Patella
Tibia / Fibula
Ligamentous Anatomy of the Knee
ACL, PCL, LCL, MCL
MPFL
Posterolateral Corner
Chondral Anatomy of the Knee
Menisci
Chondral Cartilage
Muscular Anatomy:
Knee extensors
(Quad muscles)
Vastus Medialis
Vastus intermedius
Vastus Lateralis
Rectos Femoris
Muscular Anatomy:
Knee Flexors
(Hamstring muscles)
Semimembranosus
Semitendinosus
Biceps Femoris
Gracilis
Popliteus
Gastrocnemius
Muscular Anatomy:
Hip rotators
TFL and Glute Max into IT Band
Sartorius
Adductors
Tibiofemoral Joint
Structure
~Distal FEMUR approximating with proximal TIBIA
~Double Condyloid
~3 DOF
Tibiofemoral Joint
Osteokinematics
~Sagittal plane - flexion / extension around coronal axis
~Transverse plane - ER / IR around longitudinal axis
~Frontal plane - abduction/ adduction around A-P axis
Tibiofemoral Joint:
Femur
~Femoral condyles are medial to the head due to obliquity
~Medial condyle extends further creating a parallel surface to the ground
~Femoral condyles have a convex surface
~Intercondylar notch
Tibiofemoral Joint:
Tibia
~Relatively flat compared to femoral condyles
~Asymmetrical plateaus = medial > lateral
~Tibial plateau has a posterior slope of 7-10 degrees
Which osteokinematic motion does the tibial plateau angle/ posteriorslope assist with?
Flexion / Extension
Tibiofemoral Joint:
Weight bearing
Q-Angle
~Physiologic angulation
~Normal: 180-185 degrees
~Genu Valgum > 185 deg
~Genu Varum < 175 deg
Menisci Role
~Attached to the tibial plateau
~Greater contact area between surfaces
~Reduces stress/friction
~Enhance stability
~Shock absorption
Menisci Anatomy
~Fibrocartilaginous disc
~Semicircular / wedge shape
~Attached via roots, ligaments, capsule
~Compression 1-2x BW, 3-4x/BW
2 Menisci
Medial Meniscus
~Larger ‘C’ shape
~More ligamentous attachments, less mobile
Lateral Meniscus
~Smaller ‘O’ shape
~More mobile
Menisci Nutrition
~Blood supply - White vs Red Zones
—->More blood supply in the lateral aspects of menisci
~Innervation - anterior and posterior horns well innervated
~Central portions receive nutrients via reciprocal loading and diffusion through synovial fluid
Menisci Wedge
Allows for axial load to disperse radially “hoop stress”
Menisci Movement
~Allows for best joint congruency during knee motion
~Compressive forces increase at end ranges of motion
~Injury can occur POSTERIOR horn at end range FLEXION
~Injury can occur to ANTERIOR horn at end range EXTENSION
Tibiofemoral Joint:
Joint Capsule
~Poor boney congruency, more reliance on inert structures
~Synovial layer - meant to secrete and absorb fluid, providing nutrients and lubrication
~Strongly innervated to provide feedback -nociceptors and mechanoreceptors
Joint Capsule
Extension
Bony congruence and ligaments most taught “closed pack”
Joint Capsule
Flexion
Passive structures get more lax, allowing more translation/ rotation of tibiofemoral joint “open pack”
Joint Capsule
Anterior Portion
~Medial/lateral retinaculum
~Medial patellofemoral ligament (MPFL)
Joint Capsule
Medial Portion
Medial collateral ligament (deep and superficial)