Knee Presentation

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Knee Presentation

  1. 1. Injuries of the Knee Joint<br />Andrew Bonett<br />M.S.M.S. Anatomy<br />University of South Florida<br />July 16, 2009<br />
  2. 2.
  3. 3. Gross Anatomy: Bones<br />intercondylar eminence<br />patellar surface<br />
  4. 4. Gross Anatomy: Skeletal Structure<br />22<br />
  5. 5. Gross Anatomy: Articular Surfaces<br />
  6. 6. Gross Anatomy: Menisci<br /><ul><li> Fibrocartilaginous structures
  7. 7. Attach to tibia in intercondylar region
  8. 8. Transverse ligament connects the anterior horns of each menisci
  9. 9. Vascular periphery (2-3 mm)
  10. 10. Medial meniscus
  11. 11. Oval-shaped
  12. 12. Attached to MCL
  13. 13. Thinner , less mobile
  14. 14. Lateral meniscus
  15. 15. Circular
  16. 16. Thicker, more mobile</li></li></ul><li>Gross Anatomy: Synovial Membrane<br />Bursae:<br /><ul><li>Suprapatellar
  17. 17. Subpopliteal
  18. 18. Prepatellar
  19. 19. Subcutaneous </li></ul>infrapatellar<br /><ul><li>Deep infrapatellar</li></ul>PCL<br />MM<br />LM<br />ACL<br />Does not invest cruciate ligaments!<br />
  20. 20. Gross Anatomy: Ligaments<br />Medial Collateral (MCL)<br />Lateral Collateral (LCL)<br />Anterior Cruciate (ACL)<br />Posterior Cruciate (PCL)<br />Meniscofemoral (MFL)<br />Meniscofemoral<br />ligament<br />
  21. 21. Gross Anatomy: Muscles<br />Thigh<br />Quadriceps femoris – VL, VM, VI, RF<br />Sartorius<br />Gracilis<br />Hamstrings – BF, SM, ST<br />IT band – GM, TFL<br />Leg<br />Gastrocnemius<br />Plantaris<br />Popliteus<br />(Pes anserinus)<br />
  22. 22. Gross Anatomy: Popliteal Fossa<br />1. Semitendinosus<br />2. Biceps femoris<br />3. Semimembranosus<br />4. Sciatic nerve<br />5. Popliteal vein<br />6. Popliteal artery<br />Common peroneal n.<br />Tibial n.<br />
  23. 23. Gross Anatomy: Vasculature<br /><ul><li>Popliteal Artery
  24. 24. Med./Lat. Superior Genicular
  25. 25. Middle Genicular – enters capsule post. to supply ligaments and synovium
  26. 26. Med./Lat. Inferior Genicular
  27. 27. Circumflex Fibular</li></ul>Patellar Plexus<br />Anastomoses of descending branch of lateral circumflex femoral a., anterior tibial recurrent a., and genicular branches<br />
  28. 28. Gross Anatomy: Nerve Supply<br />Sciatic nerve<br />Tibial n.<br />Common peroneal n.<br />Wraps around head of fibula<br />Saphenous branches<br />Run deep to pes anserinus<br />
  29. 29. Patellar Dislocation<br />Predisposition<br />Genu valgum<br />Overweight<br />Patellar hypermobility<br />Weak quadriceps <br />Mechanisms<br />Direct contact to medial side<br />External tibial rotation with forceful quadriceps contraction<br />
  30. 30. Patellar Dislocation<br />Vastus medialis strain<br />Tearing of medial patellar retinaculum<br />Hemarthrosis <br />Reduces with extension <br />
  31. 31. Patellar Dislocation: Diagnosis<br />Obvious if not yet reduced<br />Patellar hypermobility/ apprehension test<br />X-ray/MRI only necessary to rule out osteochondral fractures, other associated injuries<br />
  32. 32. Patellar Dislocation: Treatment<br />Knee extension<br />Aspiration to relieve discomfort and check for fat in blood<br />Surgery unnecessary unless osteochondral fracture or complete rupture of MPFL<br />Crutches, PRICES<br />Rehabilitation focusing on vastus medialis<br />
  33. 33. Meniscal Tears<br />Shear force from femur<br />Acute or degenerative<br />Athletes, elderly, overweight<br />Vascular zone?<br />Horizontal<br />Within substance<br />Longitudinal<br />Bucket handle – ACL risk<br />Radial or vertical<br />Parrots beak<br />
  34. 34. Medial Meniscus Tear<br />Tears easier than lateral due to certain traits<br />Squatting<br />Internal rotation of tibia with knee flexed<br />Member of “unhappy triad”<br />Medial meniscus<br />MCL<br />ACL<br />
  35. 35. Medial Meniscus: Diagnosis<br />Examination<br />McMurray’s test<br />Apley’s compression test<br />MRI<br />Low-signal intensity (black triangle ) = normal<br />White interruption = lesion<br />Arthroscopy as last resort <br />
  36. 36. Medial Meniscus: Treatment<br />PRICES for isolated and minimal tear<br />Partial arthroscopic meniscectomy most common<br />
  37. 37. Lateral Meniscus Tear<br />Lower incidence<br />Often more painful<br />More likely to incur radial or parrots beak<br />Not rare for anterior horn <br />Discoid meniscus<br />Wrisberg variety<br />Congenital (1.5-3%)<br />MM only 0.1 – 0.3%<br />femur<br />Discoid meniscus<br />
  38. 38. Lateral Meniscus: Diagnosis/Treatment<br />Same techniques as for medial meniscus<br />McMurray’s test and Apley’s test performed with internal tibial rotation<br />MRI slightly less accurate than with MM<br />Treatment similar<br />
  39. 39. Medial Collateral Ligament <br />Attached to fibrous capsule and MM<br />Injury rarely isolated – “unhappy triad”<br />Can tear with external rotation (skiing), but more commonly from valgus or abduction force (football)<br />Pain localized to medial joint line, but can subside following Grade III tear<br />Leads to further injury<br />
  40. 40. MCL: Diagnosis: Examination<br />Abduction stress test<br />First at 30<br />Again at full extension<br />Rule out PCL tear<br />Anterior drawer test with external rotation of tibia<br />Hip flexed 45<br />Knee flexed 90<br />Tibia rotated 30 ext.<br />Anterior rotation of medial tibial condyle<br />
  41. 41. MCL: Diagnosis: Imaging<br />X-ray<br />Only useful for young patients to differentiate from epiphyseal fracture<br />Taken at 20-30 flexion<br />Enlarged joint space = tear<br />MRI<br />Coronal scan<br />Normal MCL looks thin, taut, low-signal<br />Grade I: indistinct MCL (edema)<br />Grade II: thicker, looser<br />Grade III: severe edema <br />
  42. 42. MCL: Treatment<br />Surgery necessary for compound injury<br />Crutches + PRICES + rehab for Grade I, II onlyif isolated<br />Grade III tears may require surgical repair, but immobilization can be effective if isolated (rare)<br />3-4 months recovery<br />Surgery<br />Open incision<br />Midsubstance ruptures sutured<br />Tear from bone repaired with suture anchors<br />
  43. 43. Lateral Collateral Ligament<br />Courses slightly posterior<br />Sprained least frequently<br />Adduction force rare<br />BF, popliteus, IT tract<br />Flexed knee = isolated tear<br />Anteromedial blow  hyperextension/ postero-lateral corner injury<br />Risk to common peroneal nerve<br />Foot drop, sensation loss<br />
  44. 44. LCL: Diagnosis: Examination<br />Adduction stress test<br />At 30, then full extension<br />Ext. rotation recurvatum<br />Lift legs by great toes<br />Recurvatum + ext rotation + varus = PL corner injury<br />Posterolateral drawer test<br />Tibia externally rotated, posterior force applied<br />Reverse pivot shift test<br />Knee 90, tibia ext. rotated<br />With valgus, slowly extended<br />Temporary posterior subluxation of lateral tibial condyle around 30<br />Forcibly reduces with extension<br />
  45. 45. LCL: Imaging and Treatment<br />MRI<br />Coronal oblique scan<br />Sagittal scan to rule out fibular fracture, avulsion<br />Tear looks less taut or discontinuous – no thickening<br />Treatment<br />Similar to MCL<br />Grade III usually requires surgery<br />
  46. 46. Anterior Cruciate Ligament<br />Most common knee injury among athletes<br />AM fibers taut in flexion<br />Check anterior displacement<br />PL fibers taut in extension<br />Check rotation<br />Hyperextension, internal rotation – rarely isolated injury from contact force<br />“unhappy triad”<br />May tear from tibia (3-10%), from femur (7-20%), or in midportion (70%)<br />Proximal end receives branch from middle genicular a.<br />(LEFT KNEE)<br />Internal rotation of right knee<br />
  47. 47. ACL: Diagnosis: Examination<br />History, large hemarthrosis<br />Autonomic symptoms<br />Anterior drawer test<br />Tibia neutral, pull ant.<br />NOT RELIABLE BY ITSELF<br />Lachman test<br />Knee only flexed 15-20<br />Pivot shift/jerk test<br />Start in extension, tibia internally rotated, valgus<br />Slowly flex, lateral tibial condyle temporarily subluxates anteriorly ~30<br />Reduces with further ext.<br />Jerk test opposite (90 o)<br />
  48. 48. ACL: Diagnosis: Imaging<br />X-ray <br />Segond fracture of lateral tibial condyle<br />ACL tear with it 75-100%<br />Tibial spine avulsion in young patients<br />MRI – 95% accuracy<br />All 3 planes in full extension<br />Edema/hemorrhage often obscures ACL<br />Normal ACL<br />Torn ACL<br />
  49. 49. ACL: Treatment<br />Extrasynovial, heals poorly<br />Partial, isolated tears may be treated with PRICES, rehab, bracing of slightly flexed knee<br />Most tears, athletes will require reconstruction<br />
  50. 50. Posterior Cruciate Ligament<br />Broader, longer, stronger<br />PM and AL fiber bundles<br />Receives better vasc. from MGA, synovial membrane<br />Checks post. displacement<br />Tears much less frequently<br />Only in isolation when “dashboard knee” injury<br />Hyperextension in sports, especially with side force<br />Falling to ground with foot plantar flexed<br />Posterior view<br />Medial femoral condyle<br />Anterior view<br />
  51. 51. PCL: Diagnosis<br />Posterior drawer test<br />Neutral start vital!<br />Gravity or sag test<br />Hips at 45or 90, compare tibial tuberosities for sag<br />Abduction/adduction stress test at full extension<br />X-ray to confirm sag test<br />MRI shows lower-signal intensity for intact PCL compared to ACL due to its fiber organization<br />Take on all 3 axes, but best is sagittal oblique<br />negative<br />positive<br />
  52. 52. PCL: Treatment<br />Controversial <br />PRICES , rehab, bracing for most isolated tears<br />Rehab focused on quadriceps muscles for compensatory anterior drawer<br />Surgery avoided when possible because PCL not easy to access without additional risk factors<br />Prognosis good because better blood supply = revascularization<br />
  53. 53. Cruciate Ligament Reconstruction<br />Complete excision followed by graft insertion<br />Allograft<br />Autograft<br />Patellar, quadriceps, hamstrings, calcaneus tendons used<br />Undergoes biological modifications: inflamed, necrotic  revascularization  extrinsic fibroblasts repopulate<br />
  54. 54. ACL Reconstruction<br />Autografts<br />B-PT-B<br />Quadruple hamstrings<br />Semitendinosus, gracilis<br />Only replace AM <br />Double-Bundle<br />Provides rotational stability<br />BTB as AM bundle<br />Fixed at 20<br />ST as PL bundle<br />Fixed at 90<br />
  55. 55. PCL Reconstruction<br />Usually allograft – calcaneus tendon<br />Incorporates well with long-term stability<br />BTB and ST often too short<br />Can achieve full function with reconstruction of just AL bundle<br />A<br />B<br />A. Low-power view cross section of PCL 11 years after calcaneus tendon graft. B. High-power<br />
  56. 56. Future of Reconstruction<br />Goals:<br />Improve recovery time<br />Improve remodeling of insertion sites<br />Improve nervous and vascular restoration<br />With biological manufacture of:<br />Growth factors, cytokines<br />Antibiotics <br />Techniques:<br />Gene therapy – viral/non-viral vector delivers specific gene<br />Tissue engineering – mesenchymal stem cells<br />

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