Slide 1

The Knee ESAT 3600 Fundamentals of Athletic Training Slide 2 Knee Complex 2 articulations Tibiofemoral (knee joint) Medial and lateral Patellofemoral Slide 3 Tibiofemoral Joint Articulation of the femur and tibia Medial and lateral articulating surfaces Femur has convex surfaces Tibia has concave surfaces Slide 4 Patellofemoral Joint Articulation of patella with femur Patella serves as pulley mechanism for quadriceps muscles PFPS Chondromalacia Slide 5 Bony Landmarks (Femur) Lateral condyle Lateral epicondyle Medial condyle Medial epicondyle Adductor tubercle Popliteal fossa Intercondylar notch Patellar facet Slide 6 Bony Landmarks (Tibia) Tibial tuberosity Pes Anserines Gerdys Tubercle Slide 7 Pes Anserines Point of insertion of sartorius, gracilis, and semitendinosus Slide 8 Gerdys Tubercle Small prominence on anterior aspect of lateral condyle of tibia Insertion of IT band Slide 9 Superior View of Tibia Intercondylar fossa Posterior Anterior Intercondylar eminence Medial articular surface Lateral articular surface Slide 10 Patella Base Apex Lateral border Medial border Lateral articulating surface Medial articulating surface Slide 11 Knee Movements Flexion Extension Medial rotation Lateral rotation Slide 12 Arthrokinematics of Tibiofemoral Extension Matter of perspective Tibia moving on fixed femur Femur moving on fixed tibia Slide 13 Screw-Home Mechanism 3 factors Shape of medial condyle Passive tension of ACL Lateral pull of quadriceps Also a matter of perspective External rotation of tibia on femur Internal rotation of femur on fixed tibia Slide 14 Patellofemoral Joint Kinematics Slide 15 Knee Stability Bony stability is extremely weak Ligaments and cartilage provide most stability Slide 16 Menisci and Attachment Sites Medial C-shaped Lateral Incomplete O Slide 17 Ligament of Wrisberg Lateral meniscus to posterior medial condyle Slide 18 4 Main Functions of Menisci Maintain congruence between articular surfaces in all positions of the joint Provide shock absorption in the joint Maintain circulation of synovial fluid through articular cartilages Help bring about normal movement between the articular surfaces Slide 19 Meniscal Injury Tearing attachments of the menisci to the tibial table and joint capsule Crushing the menisci between the femoral and tibial condyles, produces circular (bucket handle) and radial tears Slide 20 Joint Capsule Common capsule for tibiofemoral and patellofemoral joints Anterior part folds upward during extension Posterior part folds downward during flexion Slide 21 Knee Ligaments Lateral collateral Attached superiorly to lateral epicondyle, inferiorly to head of fibula Medial collateral Attached superiorly to medial epicondyle, inferiorly to medial aspect of tibia below tibial condyle Slide 22 Knee Ligaments Anterior cruciate Distal attachment posterior aspect of anterior intercondylar area of tibia Proximal attachment posterior medial aspect of lateral femoral condyle Slide 23 ACL Anteriomedial band Tight in flexion Posteriolateral band Tight in extension Both are tight in extension PL band is more tight Slide 24 Knee Ligaments Posterior cruciate Distal attachment posterior aspect of posterior intercondylar area of tibia Proximal attachment anterior inferior lateral aspect of medial femoral condyle Slide 25 Role of Cruciate Ligaments Bring about normal movement between articular surfaces ACL prevents anterior displacement of tibia relative to femur Prevents medial rotation PCL prevents posterior displacement of tibia relative to femur Slide 26 Posterior Knee Ligaments Oblique popliteal ligament Runs from posterior aspect of the lateral condyle of femur to posterior edge of medial condyle of the tibia Protects against hyperextension Slide 27 Posterior Knee Ligaments Arcute ligament Runs from the posterior aspect of the lateral condyle to the posterior surface of capsular ligament Protects against hyperextension Slide 28 Ligamentous Stability in General Not constant throughout ROM Knee extended most stable Knee flexed least stable Slide 29 Patellofemoral Restrains Slide 30 Forces Acting on the Patella Slide 31 Q Angle Pull angle of the quadriceps 8 17 degrees is normal Increased angles associated with patellofemoral problems Slide 32 Knee Alignments Genu valgum Genu varum Genu recurvatum Slide 33 Knee Function Dual role of mobility and stability Mobile enough to allow movement Stabile enough to absorb forces Gait and hamstrings Slide 34 Muscles Covered With the Hip Sartorius Rectus Femoris Tensor Facia Lata Gracilis Biceps Femoris Semitendinosis Semimembranosus See book for review Slide 35 Vastus Medialis O: lower of intertrochanteric line, medial lip of linea aspera, upper part of medial supracondylar line, medial intermuscular septum, tendon of adductor magnus and longus I: medial border of patella, through patellar ligament to tibial tuberosity A: extends the leg at the knee and draws patella medially Slide 36 Vastus Intermedius O: proximal 2/3 of the anterolateral surface of femur, lower of the linea aspera, upper part of lateral intermuscular septum I: by tendons of rectus femoris and vasti muscles into superior border of patella, through patellar ligament to tibial tuberosity A: extends leg at knee Slide 37 Vastus Lateralis O: upper part of intertrochanteric line, anterior and lower borders of greater trochanter, lateral lip of gluteal tuberosity, upper half of linea aspera, lateral intermuscular septum, and tendon of the gluteus maximus I: lateral border of patella and through patellar ligament to tibial tuberosity A: Extends leg at knee and draws patella leterally Slide 38 Popliteus O: lateral condyle of femur, outer margin of lateral meniscus, arcuate popliteal ligament and capsule of knee joint I: posterior surface of tibia above soleal line A: rotates the tibia medially on the femur, or the femur laterally on the tibia (depends on the one fixed) Slide 39 Gastrocnemius O: lateral condyle and posterior surface of femur, capsule of knee joint. Medial condyle and adjacent part of femur I: posterior surface of calcaneus by means of achilles tendon A: flexes leg at the knee, plantar flexion and inversion of foot Slide 40 Muscle Action Around the Knee All create stability of joint Hamstrings help prevent ATD 2-Joint arrangement provides efficiency of movement 2-joint arrangement can lead to problems Passive insufficiency Active insufficiency Slide 41 Knee Extensor Mechanism Slide 42 Biomechanical Considerations of Knee Extension Slide 43 Knee Instability Knee is prone to instability and injury Continuous stress Beyond limit of ROM Rotation with foot fixed Most rotation with knee flexed Mobile adapter for twisting/turning Slide 44 Deep Squats Safety dependent on how performed Ability of knee to absorb forces dependent on: Speed of descent Size of calves and thighs Strength of muscles controlling movement Slide 45 Deep Squats Dangerous when center of knee rotation is changed because of calf and thigh tissues pressing together Lean forward at trunk to adjust center of gravity towards knees Muscle strength