Slide 1

Knee Ligament Injuries Slide 2 Overview Ligament Anatomy Biomechanics Ligament Specific Epidemiology Classification Clinical exam Imaging Tx Slide 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) Slide 4 Anatomic Features Bonding Crimping Random collagen alignment Complex blood supply Diffusion from synovium Proprioception and nociception Slide 5 Biomechanics Laxity Stiffness Strength Viscoelastic behavior (creep, stress relaxation, hysteresis) Dynamic properties Slide 6 Slide 7 Ligament healing Immobilization Loading dramatically affects recovery of normal mechanical properties Decrease strength Insertion site vs. midsubstance Exercise Favourable effect Slide 8 Epidemiology Increasing incidence Combined injuries common Females > males Conditioned vs. unconditioned Slide 9 Conditioned Slide 10 Unconditioned Slide 11 ACL Anatomy Intracapsular Extrasynovial Varied blood supply FAMPLE Origin / Insertion Slide 12 ACL Function Limit anterior displacement 2 0 restraint rotation 2 0 restraint varus / valgus in extension Slide 13 Mechanism / Hx Usually noncontact Change direction Stop / jump Audible pop Instability Swelling Slide 14 General Ligament Exam Difficult acutely Early exam beneficial Pt. relaxed Displacement Endpoint quality Compare Slide 15 ACL Exam Lachman best Pivot Shift diagnostic Anterior drawer chronic tear Associated injuries Slide 16 ACL Imaging XRAY R/O # ACL avulsion Segond # Arthrography - poor Arthroscopy - gold standard Slide 17 ACL MRI 95% accurate Low signal intensity Saggital view Acute injury high signal intensity on T 2 image Bone bruising Slide 18 ACL Tx Pt selection Operative vs. Non-operative Demand level Modify lifestyle ACL dependent Other lesions Slide 19 Non-operative Acutely splint & crutches Early active ROM Closed chain WB to strengthen Avoid high risk Functional bracing controversial Slide 20 Operative Pt selection High demand Young Good ROM Open vs. endosopic Learning curve Slide 21 Slide 22 Graft Auto vs. allo Collagen lattice Resorption revascularization restructuring Bone-patellar tendon-bone Semitendinosus/gracilis tensioning Slide 23 Rehab Closed kinetic chain strengthening Acutely fixation weak Graft weakest 6-12 wks Outcome >90% stable 3-5 yrs Slide 24 MCL Anatomy Origin femoral condyle Insertion 4cm below joint line + posterior obl. Lig. + middle capsular ligament Parallel collagen Slide 25 MCL Most common isolated ligament injury Valgus force Post. Obl. Lig. damage with rotn. injury Associated ACL common Slide 26 MCL exam Valgus force Flex. 30 0 isolated Extension Assoc. POL,ACL,PCL 5-8 mm difference significant Swelling Hemarthrosis vs. soft tissue Slide 27 MCL Tx Non-surgical RICE Bracing Strengthening Functional brace Slide 28 MCL Classification / Tx Grade 1 : 1-5 mm Symptomatic Tx Grade 2 : 610 mm Hinge brace 2-3 wks Grade 3 : 11-15 mm Hinge brace 3-4 wks Physio Slide 29 PCL Injury 1.5 x ACL strength 5% all knee lig. inj. 1 0 restraint post. translation tibia Forced flexion Dashboard Associated injuries Slide 30 PCL Pain Usually stable Posterior subluxation Medial & patellofemoral OA Slide 31 PCL exam Posterior drawer test best Grade I - III Quadriceps active test Post sag sign Slide 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 Slide 33 PCL Tx Repair : Associated posterolateral corner Associated ACL / MCL Grade 3 Drawer test Bony avulsion 20% athletes with isolated injury require repair Slide 34 Operative Repair Require good ROM pre-op Graft > 40mm No good rehab protocol Slide 35 Posterolateral Complex Combination of Structures ITB biceps femoris fibular collateral Popliteus complex Capsule etc Slide 36 Posterolateral corner Usually assoc with: PCL Knee dislocation Rarely ACL Instability esp descending inclines Peroneal N. inj. 10% pain Slide 37 Biomechanical Increased: External tibial rotation Varus rotation Posterior tibial translation Slide 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 Slide 39 Operative 1 0 Repair Acute injury Bony avulsion Reconstruction Biceps tenodesis / arcuate lig advancement : mixed results Graft - results pending Varus malalignment - HTO Slide 40 Conclusion Common injuries Easily missed Large area Ongoing research