27. Circumflex FibularPatellar Plexus Anastomoses of descending branch of lateral circumflex femoral a., anterior tibial recurrent a., and genicular branches
28. Gross Anatomy: Nerve Supply Sciatic nerve Tibial n. Common peroneal n. Wraps around head of fibula Saphenous branches Run deep to pes anserinus
29. Patellar Dislocation Predisposition Genu valgum Overweight Patellar hypermobility Weak quadriceps Mechanisms Direct contact to medial side External tibial rotation with forceful quadriceps contraction
30. Patellar Dislocation Vastus medialis strain Tearing of medial patellar retinaculum Hemarthrosis Reduces with extension
31. Patellar Dislocation: Diagnosis Obvious if not yet reduced Patellar hypermobility/ apprehension test X-ray/MRI only necessary to rule out osteochondral fractures, other associated injuries
32. Patellar Dislocation: Treatment Knee extension Aspiration to relieve discomfort and check for fat in blood Surgery unnecessary unless osteochondral fracture or complete rupture of MPFL Crutches, PRICES Rehabilitation focusing on vastus medialis
33. Meniscal Tears Shear force from femur Acute or degenerative Athletes, elderly, overweight Vascular zone? Horizontal Within substance Longitudinal Bucket handle – ACL risk Radial or vertical Parrots beak
34. Medial Meniscus Tear Tears easier than lateral due to certain traits Squatting Internal rotation of tibia with knee flexed Member of “unhappy triad” Medial meniscus MCL ACL
35. Medial Meniscus: Diagnosis Examination McMurray’s test Apley’s compression test MRI Low-signal intensity (black triangle ) = normal White interruption = lesion Arthroscopy as last resort
36. Medial Meniscus: Treatment PRICES for isolated and minimal tear Partial arthroscopic meniscectomy most common
37. Lateral Meniscus Tear Lower incidence Often more painful More likely to incur radial or parrots beak Not rare for anterior horn Discoid meniscus Wrisberg variety Congenital (1.5-3%) MM only 0.1 – 0.3% femur Discoid meniscus
38. Lateral Meniscus: Diagnosis/Treatment Same techniques as for medial meniscus McMurray’s test and Apley’s test performed with internal tibial rotation MRI slightly less accurate than with MM Treatment similar
39. Medial Collateral Ligament Attached to fibrous capsule and MM Injury rarely isolated – “unhappy triad” Can tear with external rotation (skiing), but more commonly from valgus or abduction force (football) Pain localized to medial joint line, but can subside following Grade III tear Leads to further injury
40. MCL: Diagnosis: Examination Abduction stress test First at 30 Again at full extension Rule out PCL tear Anterior drawer test with external rotation of tibia Hip flexed 45 Knee flexed 90 Tibia rotated 30 ext. Anterior rotation of medial tibial condyle
41. MCL: Diagnosis: Imaging X-ray Only useful for young patients to differentiate from epiphyseal fracture Taken at 20-30 flexion Enlarged joint space = tear MRI Coronal scan Normal MCL looks thin, taut, low-signal Grade I: indistinct MCL (edema) Grade II: thicker, looser Grade III: severe edema
42. MCL: Treatment Surgery necessary for compound injury Crutches + PRICES + rehab for Grade I, II onlyif isolated Grade III tears may require surgical repair, but immobilization can be effective if isolated (rare) 3-4 months recovery Surgery Open incision Midsubstance ruptures sutured Tear from bone repaired with suture anchors
43. Lateral Collateral Ligament Courses slightly posterior Sprained least frequently Adduction force rare BF, popliteus, IT tract Flexed knee = isolated tear Anteromedial blow hyperextension/ postero-lateral corner injury Risk to common peroneal nerve Foot drop, sensation loss
44. LCL: Diagnosis: Examination Adduction stress test At 30, then full extension Ext. rotation recurvatum Lift legs by great toes Recurvatum + ext rotation + varus = PL corner injury Posterolateral drawer test Tibia externally rotated, posterior force applied Reverse pivot shift test Knee 90, tibia ext. rotated With valgus, slowly extended Temporary posterior subluxation of lateral tibial condyle around 30 Forcibly reduces with extension
45. LCL: Imaging and Treatment MRI Coronal oblique scan Sagittal scan to rule out fibular fracture, avulsion Tear looks less taut or discontinuous – no thickening Treatment Similar to MCL Grade III usually requires surgery
46. Anterior Cruciate Ligament Most common knee injury among athletes AM fibers taut in flexion Check anterior displacement PL fibers taut in extension Check rotation Hyperextension, internal rotation – rarely isolated injury from contact force “unhappy triad” May tear from tibia (3-10%), from femur (7-20%), or in midportion (70%) Proximal end receives branch from middle genicular a. (LEFT KNEE) Internal rotation of right knee
47. ACL: Diagnosis: Examination History, large hemarthrosis Autonomic symptoms Anterior drawer test Tibia neutral, pull ant. NOT RELIABLE BY ITSELF Lachman test Knee only flexed 15-20 Pivot shift/jerk test Start in extension, tibia internally rotated, valgus Slowly flex, lateral tibial condyle temporarily subluxates anteriorly ~30 Reduces with further ext. Jerk test opposite (90 o)
48. ACL: Diagnosis: Imaging X-ray Segond fracture of lateral tibial condyle ACL tear with it 75-100% Tibial spine avulsion in young patients MRI – 95% accuracy All 3 planes in full extension Edema/hemorrhage often obscures ACL Normal ACL Torn ACL
49. ACL: Treatment Extrasynovial, heals poorly Partial, isolated tears may be treated with PRICES, rehab, bracing of slightly flexed knee Most tears, athletes will require reconstruction
50. Posterior Cruciate Ligament Broader, longer, stronger PM and AL fiber bundles Receives better vasc. from MGA, synovial membrane Checks post. displacement Tears much less frequently Only in isolation when “dashboard knee” injury Hyperextension in sports, especially with side force Falling to ground with foot plantar flexed Posterior view Medial femoral condyle Anterior view
51. PCL: Diagnosis Posterior drawer test Neutral start vital! Gravity or sag test Hips at 45or 90, compare tibial tuberosities for sag Abduction/adduction stress test at full extension X-ray to confirm sag test MRI shows lower-signal intensity for intact PCL compared to ACL due to its fiber organization Take on all 3 axes, but best is sagittal oblique negative positive
52. PCL: Treatment Controversial PRICES , rehab, bracing for most isolated tears Rehab focused on quadriceps muscles for compensatory anterior drawer Surgery avoided when possible because PCL not easy to access without additional risk factors Prognosis good because better blood supply = revascularization
53. Cruciate Ligament Reconstruction Complete excision followed by graft insertion Allograft Autograft Patellar, quadriceps, hamstrings, calcaneus tendons used Undergoes biological modifications: inflamed, necrotic revascularization extrinsic fibroblasts repopulate
54. ACL Reconstruction Autografts B-PT-B Quadruple hamstrings Semitendinosus, gracilis Only replace AM Double-Bundle Provides rotational stability BTB as AM bundle Fixed at 20 ST as PL bundle Fixed at 90
55. PCL Reconstruction Usually allograft – calcaneus tendon Incorporates well with long-term stability BTB and ST often too short Can achieve full function with reconstruction of just AL bundle A B A. Low-power view cross section of PCL 11 years after calcaneus tendon graft. B. High-power
56. Future of Reconstruction Goals: Improve recovery time Improve remodeling of insertion sites Improve nervous and vascular restoration With biological manufacture of: Growth factors, cytokines Antibiotics Techniques: Gene therapy – viral/non-viral vector delivers specific gene Tissue engineering – mesenchymal stem cells
