1. Anatomy, Joint Orientation and Arthrokinematics
Knee

2. Tibiofemoral Joint
Femur run in a medial and inferior oblique direction
Sits on a vertical tibia

3. Tibiofemoral Joint Femoral condyles are convex
Articular surface of medial femoral and tibial condyle larger
Poor congruency between the articulating surfaces

4. Menisci Fibro cartilaginous disks Thicker peripherally
Good blood supply outer 1/3
Rest Avascular

5. Menisci Roles within the knee Increase congruency
Distribute weight bearing across the knee
Act as shock absorbers
Aid lubrication reducing friction
Add nutrition to articular cartilage
Aid the locking mechanism of the knee

6. Medial Menisci Larger than lateral C Shaped Larger posteriorly
Anchored to medial capsule and MCL
Anterior horn connects with transverse ligament
Lots of ligamentous and capsular restraints
Limits mobility increasing injury risk

7. Lateral Menisci More Circular More Mobile
Medial and lateral meniscus move posteriorly with flexion
Medial and lateral meniscus move anteriorly with extension
If a tear occurs, normal movement is lost, causing locking

8. Ligaments Coronary Ligament Part of the joint capsule
Connect meniscu to tibial plateau
Often injured in twisting injuries

9. Ligaments Transverse Ligament
Connects the anterior horns of the medial and lateral menisci together

10. Ligaments Meniscofemoral Ligament
Posterior horn of lateral menisci to medial femoral condyle
Anterior and Posterior Divisions

11. Medial Collateral Ligament
Strong flat ligament
Merges with adductor magnus fibres
Deep portion attaches to medial meniscus
Deep portion capsular thickening
Seperated by pes anserinus tendons by bursa
Resists valgus force to the knee and external rotation of the tibia

12. Lateral Collateral Ligament
Cord like ligament
Extracapsular
More flexible than MCL
Resists varus stress
Resists tibial external rotation

13. Anterior Cruciate Ligament
Medial tibia to lateral femoral condyle
2 bands
Anteromedial
Taut in knee flexion
Posterolateral
Taut in knee extension
Resists anterior translation of tibia on femur and hyperextension of knee

14. Anterior Cruciate Ligament
Secondary restraint of varus/valgus motion
Prevents continued femoral posterior translation during closed chain flexion
Intracapsular but extrasynovial
Blood vessels form a periligamentous sheath around the ligament
Mechanoreceptors found in femoral attachment

15. Posterior Cruciate Ligament
Posterior intercondylar area of tibia to medial condyle of femur
Twice as strong as ACL
2 Bands
Anterolateral
Posteromedial
Merges with posterior horn of lateral menisci and meniscofemoral ligament

16. Posterior Cruciate Ligament
Restricts posterior translation of tibia on femur and external rotation of tibia
Secondary restraint of varus/valgus motion
Intracapsular, but extrasynovial

17. Posterior Ligaments Oblique Popliteal Ligament
Thickening of posterior capsule
Expansion of semimembranosus tendon
Passes superior and laterally to femoral intercondylar line
Arcuate Popliteal Ligament
Inferior lateral aspect of posterior capsule
From fibula head to posterior tibial and lateral femoral condyle

18. Joint Capsule
Thick ligamentous sheath composed mainly of muscle tendons and their expansions
Deficient anteriorly due to patella

19. Bursae

20. Infrapatella Fat Pad
Sits between the joint capsule and synovial membrane
Between Patella Ligament and knee joint
Can be impinged or damaged in trauma

21. Arthrokinematics Knee Extension Open Chain Closed Chain Knee Flexion
Tibia Glides Anteriorly and Rolls Anteriorly
Tibia external rotation from 20° Flexion to Full Extension
Closed Chain
Femur Glides Posteriorly and Rolls Anteriorly
Femur Internally rotates on stable Tibia from 20° Flexion to Full Extension
Knee Flexion
Tibia Glides Posteriorly and Rolls Posteriorly
Tibia internal rotation from Full Extension to 20° Flexion
Femur Glides Anteriorly and Rolls Posteriorly
Femur Externally rotates on stable Tibia from Full Extension to 20° Flexion

22. Arthrokinematics
Extension
Flexion

23. Patellofemoral Joint Anterior surface of the femoral condyles
Posterior surface of the patella
Divided into medial and lateral facets
4-5 mm of articular hyaline cartilage on patella

24. Ligamentum Patellae (Patellar Tendon)
Continuation of quadriceps tendon
Attaches into the tibial tuberosity

25. Meniscopatellar Fibres
Fibrous bands running from patella to lateral aspect of medical and lateral menisci

26. Retinaculum Medial and Lateral
Expansions of different connective tissue
Patellofemoral and patellotibial ligaments
Vastus Medialis, Vastus Lateralis, ITB

27. Patellofemoral Joint Arthrokinematics
Articulation
Inferior margin of patella articulates with the femur at approx 10-20° of knee flexion
As knee flexion increases the contact area of the patella moves proximally
As knee flexion increase the contact area of the condyles moves posteriorly
Patella does not articular with trochlea of femur near terminal extension

28. Patellofemoral Articulations

29. Patellofemoral Articulations

30. Patellofemoral Contact Area
The larger the contact surface area the more a load can be distributed over a greater area
E.g which is more painful, a women standing on you in stilettoes or walking boots?
The contact surface of the patellofemoral joint INCREASES with flexion
@ 30° knee flexion the contact area = 2.0cm²
@ 90 ° knee flexion the contact area = 6.0cm²