1. Knee Ligament Injuries

2. Overview Ligament Anatomy Biomechanics Ligament Specific  Epidemiology  Classification  Clinical exam  Imaging  Tx

3. Ligament Anatomy Type 1 collagen (70%) Elastin Extracellular matrix Hierarchical structure Fibrils > fibres >subfascicular unit >fasciculus Longitudinal fasciculi (MCL, LCL) Helical fasciculi (ACL, PCL)

4. Anatomic Features Bonding Crimping Random collagen alignment Complex blood supply Diffusion from synovium Proprioception and nociception

5. Biomechanics Laxity Stiffness Strength Viscoelastic behavior (creep, stress relaxation, hysteresis) Dynamic properties

7. Ligament healing Immobilization  Loading dramatically affects recovery of normal mechanical properties  Decrease strength  Insertion site vs. midsubstance Exercise  Favourable effect

8. Epidemiology Increasing incidence Combined injuries common Females > males Conditioned vs. unconditioned

9. Conditioned

10. Unconditioned

11. ACL Anatomy Intracapsular Extrasynovial Varied blood supply FAMPLE Origin / Insertion

12. ACL Function Limit anterior displacement 2 0 restraint rotation 2 0 restraint varus / valgus in extension

13. Mechanism / Hx Usually noncontact Change direction Stop / jump Audible “pop” Instability Swelling

14. General Ligament Exam Difficult acutely Early exam beneficial Pt. relaxed Displacement Endpoint quality Compare

15. ACL Exam Lachman – best Pivot Shift – diagnostic Anterior drawer – chronic tear Associated injuries

16. ACL Imaging XRAY  R/O #  ACL avulsion  Segond # Arthrography - poor Arthroscopy - gold standard

17. ACL MRI 95% accurate Low signal intensity Saggital view Acute injury high signal intensity on T 2 image Bone bruising

18. ACL Tx Pt selection Operative vs. Non-operative  Demand level  Modify lifestyle  ACL dependent  Other lesions

19. Non-operative Acutely – splint & crutches Early active ROM Closed chain WB to strengthen Avoid high risk Functional bracing controversial

20. Operative Pt selection  High demand  Young  Good ROM Open vs. endosopic Learning curve

22. Graft Auto vs. allo Collagen lattice Resorption – revascularization – restructuring Bone-patellar tendon-bone Semitendinosus/gracilis tensioning

23. Rehab Closed kinetic chain strengthening Acutely fixation weak Graft weakest 6-12 wks Outcome  >90% stable 3-5 yrs

24. MCL Anatomy Origin – femoral condyle Insertion – 4cm below joint line + posterior obl. Lig. + middle capsular ligament Parallel collagen

25. MCL Most common isolated ligament injury Valgus force Post. Obl. Lig. damage with rotn. injury Associated ACL common

26. MCL exam Valgus force Flex. 30 0 – isolated Extension  Assoc. POL,ACL,PCL 5-8 mm difference significant Swelling  Hemarthrosis vs. soft tissue

27. MCL Tx Non-surgical RICE Bracing Strengthening Functional brace

28. MCL Classification / Tx Grade 1 : 1-5 mm  Symptomatic Tx Grade 2 : 6–10 mm  Hinge brace 2-3 wks Grade 3 : 11-15 mm  Hinge brace 3-4 wks Physio

29. PCL Injury 1.5 x ACL strength 5% all knee lig. inj. 1 0 restraint post. translation tibia Forced flexion Dashboard Associated injuries

30. PCL Pain Usually stable Posterior subluxation Medial & patellofemoral OA

31. PCL exam Posterior drawer test –best  Grade I - III Quadriceps active test Post sag sign

32. Non-operative Aggressive rehab Focus quadriceps No support for bracing closed kinetic chain Open kinetic chain extension avoided 90% quads strength prior to normal athletics

33. PCL Tx Repair :  Associated posterolateral corner  Associated ACL / MCL  Grade 3 Drawer test  Bony avulsion  20% athletes with isolated injury require repair

34. Operative Repair Require good ROM pre-op Graft > 40mm No good rehab protocol

35. Posterolateral Complex Combination of Structures  ITB  biceps femoris  fibular collateral  Popliteus complex  Capsule  etc

36. Posterolateral corner Usually assoc with:  PCL  Knee dislocation  Rarely ACL Instability esp descending inclines Peroneal N. inj. 10% pain

37. Biomechanical Increased:  External tibial rotation  Varus rotation  Posterior tibial translation

38. Exam Swelling / bruising Gait : Varus thrust AP translation > 30 0 than 90 0 Best tests:  Varus stress opening > 30 0 than 0 0  Prone external rotation test Other tests

39. Operative 1 0 Repair  Acute injury  Bony avulsion Reconstruction  Biceps tenodesis / arcuate lig advancement : mixed results  Graft - results pending Varus malalignment - HTO

40. Conclusion Common injuries Easily missed Large area Ongoing research