anatomy of Knee


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  • Anterior on femur
  • Posterior Cutaneous nerve of thigh <Posterior Cutaneous of calf
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  • anatomy of Knee

    1. 1. MOB TCD Knee Professor Emeritus Moira O’Brien FRCPI, FFSEM, FFSEM (UK), FTCD Trinity College Dublin
    2. 2. MOB TCD Knee Joint • • • • • Synovial condylar joint Close pack Full extension Least pack 15 degree flexion
    3. 3. MOB TCD Anatomy of Knee Joint
    4. 4. MOB TCD Bones • The articular surfaces are the medial and lateral femoral condyles (the intercondylar notch in between) • The medial condyle has a longer articular surface • The superior aspect of the medial and lateral tibial condyles • The posterior aspect of the patella
    5. 5. MOB TCD Intercondylar Notch • Average is 17 mm • Narrow notch more likely to tear ACL
    6. 6. MOB TCD Bones
    7. 7. MOB TCD Patella • • • • • Sesamoid bone Thickest articular cartilage in body Smaller medial facet Q-angle Controlled by Vastus Medialis Obliquus (VMO) and Vastus Lateralis Obliquus (VLO)
    8. 8. MOB TCD Patella • The patella is controlled by the oblique portions of the vastus medialis and vastus lateralis. • The vastus medialis wastes within 24 hours after an effusion of the knee • If the oblique fibers of the vastus medialis are wasted, the patella tends to sublux laterally on extension of the knee. This results in retropatellar pain
    9. 9. MOB TCD Patella
    10. 10. MOB TCD Weak Vastus Medialis Obliquus • Lower most fibres of vastus medialis • Partly arise adductor magnus • Straightens the pull on the quads tendon and patella • Controls patella tracking during flexion extension of the knee • Fibres atrophy quickly after knee injury • 10-15 ml of effusion inhibit VMO • VMO rehabilitation strength and timing of contraction
    11. 11. MOB TCD Deficiency of Lateral Condyle
    12. 12. MOB TCD Capsular Ligaments • • • • • • Quadriceps Retinacular fibres Patellar tendon Coronary ligaments Medial and lateral ligaments Posterior oblique ligament
    13. 13. Capsule Attachments • • • • Quadriceps tendon The patella The patellar ligament Retinacular fibres all form the anterior part of the capsule • The patellar ligament is the insertion of the quadriceps tendon MOB TCD
    14. 14. Patellar Ligament • Antero-inferiorly is attached to the tuberosity of the tibia • On either side the retinacular fibres pass upwards from the tuberosity in a V-shaped manner to be attached just below the articular margin • The deep infrapatellar bursa and infrapatellar pad of fat lie posterior to it, separating it from the tibia MOB TCD
    15. 15. Capsule Attachments • Laterally, the attachment is just beyond the articular margin • Laterally, it is attached above the groove for the popliteus, below the lateral epicondyle • There is a gap in the capsule to allow the popliteus to emerge MOB TCD
    16. 16. Capsule Attachments • Posterior • Superiorly, it is attached just beyond the articular margin and to the lower border of the popliteal surface of the femur, above the intercondylar notch MOB TCD
    17. 17. Capsule Attachments • Postero-inferiorly, the capsule is attached to the medial condyle of the tibia • By a line running above the groove for the semimembranosus tendon • Below the attachment of the posterior cruciate ligament MOB TCD
    18. 18. Capsule Attachments • Medially, the capsule is attached to the femur just beyond the articular margin of the condyle • Below the medial epicondyle MOB TCD
    19. 19. MOB TCD Collateral Ligaments Netter
    20. 20. Medial Structures • Medial ligament • Pes anserinus consists of: – Sartorius – Gracilis – Semitendinosus • Tibial inter-tendinous bursa between them MOB TCD
    21. 21. Medial Collateral Ligament (MCL) or Tibial Collateral Ligament • Is attached superiorly to the medial • • • • • • epicondyle of the femur It blends with the capsule Attached to the upper third of the tibia, as far down as the tibial tuberosity It has a superficial and deep portion The deep portion, which is short, fuses with the capsule Attached to the medial meniscus A bursa usually separates the two parts MOB TCD
    22. 22. Medial Collateral Ligament (MCL) or Tibial Collateral Ligament • The tendons of sartorius, gracilis • and semitendinosus cross its tibial attachment where another bursa is situated The anterior part tightens during the first 70–105°of flexion MOB TCD
    23. 23. MOB TCD Medial Collateral Ligament (MCL) • Medial ligament, tightens in • • • • extension And at the extremes of medial and lateral rotation A valgus stress will put a strain on the ligament If gapping occurs when the knee is extended, this is due to a tear of posterior medial part of capsule If gapping only occurs at 15º flexion, this is due to tear of medial ligament
    24. 24. MOB TCD Medial Ligament Netter
    25. 25. Posterior Medial Structures • Semimembranosus into the groove on posterior aspect of medial tibial condyle and its extensions • Upwards and lateral is oblique popliteal ligament • Downwards and lateral forms fascia covering popliteus • Downwards and medially fuses with medial ligament MOB TCD
    26. 26. Oblique Popliteal Ligament • Oblique popliteal ligament passes upwards and laterally • Fuses with the fabella if present • Capsule above lateral femoral condyle • Pierced by middle genicular vessels and nerve • Posterior division of obturator nerve • Popliteal artery lies on it MOB TCD
    27. 27. Oblique Popliteal Ligament • Strengthens the posterior portion of the capsule and prevents extreme lateral rotation • It is an expansion from the semimembranosus tendon close to its insertion to the tibia • Branch from the posterior division of the obturator nerve, pierces the ligament, supplies cruciates and articular twig to knee (referred pain from pelvic peritoneum to knee) MOB TCD
    28. 28. Lateral Structures Netter MOB TCD
    29. 29. Lateral Knee • • • Lateral ligament Iliotibial tract Arcuate complex • Fabellofibular ligament • Deep portion of capsule • Meniscotibial ligaments MOB TCD
    30. 30. MOB TCD Poster Lateral Corner • Posterior horn of lateral meniscus • Arcuate complex • Popliteus • Lateral head of gastrocnemius
    31. 31. MOB TCD Lateral Ligament • Deep in interval between iliotibial band and biceps • Lateral epicondyle of femur • Midpoint superior surface of fibula and the styloid process of the fibula • It is a cord-like structure that is separated from the capsule by the tendon of the popliteus • Surrounded by biceps Fabbriciani & Oransky, 1992
    32. 32. MOB TCD Lateral Collateral Ligament (LCL) • Deep to lateral collateral ligament • Popliteus • Inferolateral genicular vessels and nerve
    33. 33. Lateral Collateral Ligament (LCL) or Fibular Collateral Ligament • Taut in extension • 20°flexion, lateral ligament complex more lax than medial • Primary lateral restraint to varus loading • Arcuate ligament is the edge of capsule that arches above the popliteus MOB TCD
    34. 34. Arcuate Ligament • Passes from the tip of the styloid process • Just posterior to the lateral ligament • Blends origin of the lateral head of gastrocnemius and oblique popliteal ligament • Edge of capsule arches over popliteus and may give partial origin to popliteus MOB TCD
    35. 35. MOB TCD Fabella • Fabella lies at point on the poster lateral side of knee • Where multidirectional collagenous tensile stress meet • 8% - 10% osseous • 90% - 92% cartilagenous Fabbricani & Oransky, 1992
    36. 36. Coronary Ligament • Connects the periphery of the menisci to the tibia • They are the portion of the capsule that is stressed in rotary movements of the knee MOB TCD
    37. 37. MOB TCD Popliteus • Origin inferior, popliteal surface of tibia, above the soleal line, fascia of semimembranosus • Deep to arcuate popliteal ligament • Enters capsule • Crosses lateral surface of lateral meniscus • Attached by popliteal-meniscal fibres which bound hiatus
    38. 38. MOB TCD Popliteus • Enters hiatus • Crosses femoral condyle • Deep to lateral collateral ligament • Inserts into anterior part of groove • Superior popliteal recess communicates joint
    39. 39. MOB TCD Popliteus • Femoral condyles rotate medially around taut ACL during the locking mechanism of the knee • Popliteus laterally rotates the femur to unlock the knee so flexion can occur
    40. 40. MOB TCD Iliotibial Tract • The iliotibial tract is a thickening of the deep fascia of the thigh, fascia lata • The tract is attached to Gerdy’s tubercle on the anterolateral aspect of the lateral tibial condyle • The superficial three quarters of the gluteus maximus end in a thick tendinous lamina which is inserted into the iliotibial tract • The tensor fascia lata is also inserted into the tract • Gives origin to the oblique fibres of the vastus lateralis that help to stabilise the patella
    41. 41. MOB TCD Iliotibial Tract • In full knee extension the tract lies anteriorly to the line of flexion of the knee, • As it is free of bony attachments between the lateral femoral epicondyle and Gerdy’s tubercle • It is free to move posteriorly to this axis on flexion of the knee Standish & Wood, 1996. • As the tract crosses the lateral epicondyle of the femur a bursitis may develop as the result of a ‘long-leg syndrome’
    42. 42. MOB TCD Iliotibial Tract • The iliotibial band acts as an extensor of the knee when the knee is flexed from 0°to 30°and as a flexor when the knee is flexed more than 40°, due to the change in the transverse axis which occurs at 30–40°flexion. • The pelvic tilt is a mechanism for tightening the iliotibial band. The pull of the band stabilises the knee in extension, as well as helping to resist extension and adduction of the hip of the weight-bearing leg
    43. 43. MOB TCD Movements of the Knee Joint • Flexion and extension take place between the femoral condyles and the upper surface of the menisci • Rotation occurs between lower surface of the menisci and upper surface of the tibia
    44. 44. MOB TCD Extension Screw Home • Contraction of the quadriceps results in extension • The anterior cruciate becomes taut • And medial rotation of the femur occurs around the taut anterior cruciate to accommodate the longer surface of the medial condyle
    45. 45. Flexion • Femoral condyles rotate medially around taut ACL during the locking mechanism of the knee • Popliteus laterally rotates the femur to unlock the knee • So flexion can occur • Then the hamstrings flex the knee MOB TCD
    46. 46. Functional Anatomy of Patellofemoral Joint (PFJ) MOB TCD
    47. 47. MOB TCD Functional Anatomy of PFJ
    48. 48. Anterior and Posterior Cruciates • Anatomically named by their tibial attachments • Clinically femoral are called lateral origin • Covered by synovial membrane on anterior and on both sides which is reflected from capsule, • I.e. oblique popliteal ligament • Bursa between them on lateral aspect anterior MOB TCD
    49. 49. Anterior and Posterior Cruciates Ligament • Synovial membrane covers the anterior and sides of the cruciates • Not covered on posterior aspect MOB TCD
    50. 50. Anterior Cruciate • Anterior cruciate is attached to anterior aspect of the superior surface of the tibia behind • Anterior horn of medial meniscus in front of the anterior horn of the lateral meniscus • Passes upwards and laterally to the posterior aspect of medial surface of lateral femoral condyle MOB TCD
    51. 51. Superior Aspect of Tibial Plateau Menisci Anterior cruciate ligament PCL Posterior meniscofemoral ligament MOB TCD
    52. 52. Anterior Cruciate Ligament (ACL) • Three dimensional fan shaped • Multiple non-parallel interlacing collagenous fascicles MOB TCD
    53. 53. Anterior Cruciate Ligament anterior MOB TCD
    54. 54. Anterior Cruciate Ligament • Tibial attachment is in anteroposterior axis of tibia • Femoral attachment is in longitudinal axis of femur • Forms 40°with its long axis • 90°twist of fibres from extension to flexion MOB TCD
    55. 55. Anterior Cruciate Ligament • Anteromedial fibres have the most proximal femoral attachment • Contribute to anteromedial stability • Intermediate to straight and anteromedial • Posterolateral aids in anteromedial stability MOB TCD
    56. 56. Anterior Cruciate Ligament • ACL are vertical in extension • 90°flexion are horizontal • PCL are more vertical in 90°flexion MOB TCD
    57. 57. Cruciate • At 0°of flexion the fibres of the ACL are more vertical • At 90°flexion they are in the horizontal plane • Fibres of the PCL are more vertical with flexion and increasing flexion, > 90°becomes pivot • PCL is least affective at 30°flexion Hunziker et al 1992, Covey 2001 MOB TCD
    58. 58. MOB TCD ACL in Extension and 45°
    59. 59. Anterior and Posterior Cruciate • PCL • Provides 94% of restraint to posterior displacement • ACL • Provides 86% of restraint to anterior displacement MOB TCD
    60. 60. Anterior Cruciate Ligament Blood Supply • Middle genicular artery • Inferior medial genicular • Inferior lateral genicular arteries via infrapatellar fat pad • Only one main artery • Middle genicular enters upper third MOB TCD
    61. 61. Posterior Cruciate • • • • • • Strongest ligament Shorter More vertical Less oblique Twice as strong as ACL Posterior MOB TCD
    62. 62. Posterior Cruciate • PCL is the strongest ligament of the knee • It is shorter • More vertical • Less oblique • Twice as strong as ACL • Closely applied to the centre of rotation of knee • It is the principal stabiliser Hunziker et al.,1992 MOB TCD
    63. 63. Attachment of PCL • The tibial attachment of the PCL was on the sloping posterior portion of the tibial intercondylar area • Anterior to tibial articular margin • Blends with periosteum and capsule • Extended 11.5-17.3 mm distal to the tibial plateau Javadpour & O’Brien, 1992 MOB TCD
    64. 64. Tibial Attachment of the PCL Frazer, 1965 MOB TCD
    65. 65. Posterior Cruciate • Anatomically the fibres pass anteriorly and medially and proximally • It is attached on the anteroinferior part of the lateral surface of the medial femoral condyle • The area for the PCL is larger than the ACL • It expands, more on the apex of the intercondylar notch than on the inner wall Hunziker et al.1992 MOB TCD
    66. 66. Posterior Cruciate Ligament • • • • • • Three functional bands Names vary Anterior or anterolateral is larger Central Taut in flexion Posterior or posteromedial taut in extension • Posterior oblique bundle Hunziker et al 1992 MOB TCD
    67. 67. Attachment of PCL • • • • • Insertions of the PCL Passes through four zones Ligament Fibrocartilage Tidemark of mineralised fibrocartilage • Bone in less than 1 mm Cooper & Misol, 1970; Fabbriciani & Oransky, 1992 MOB TCD
    68. 68. Posterior Cruciate Ligament • Posterior oblique bundle • Most posterior fibres • Attached to posterosuperior part of femur • Posterior medial part on intercondylar area of tibia • Longest fibres • Tense in full extension Fredrick & O’Brien, 1992; Hunziker et al.,1992 MOB TCD
    69. 69. Posterior Cruciate • Proximal fibres on femur • Posterior fibres on the tibia are longest • Undergo least change MOB TCD
    70. 70. Posterior Cruciate • The PCL is located near the longitudinal axis of the knee • Medial to the centre of the knee • Vertical in frontal plane • 30°to 35°in sagittal • More horizontal in sagittal with increased flexion MOB TCD
    71. 71. Posterior Cruciate • PCL provides 94% of restraint to posterior displacement of the tibia • Prevents external rotation of tibia more at 90°than at 30° • ACL 86% of restraint to anterior displacement MOB TCD
    72. 72. Blood Supply of Cruciates MOB TCD
    73. 73. Blood Supply of Cruciates • Posterior cruciate is supplied by four branches • Distributed fairly evenly over its course • Subcortical vascular network at bony attachments • Don’t contribute much to ligaments Sick & Koritke, 1960 MOB TCD
    74. 74. Blood Supply of PCL • Main is middle genicular artery enters upper third of PCL • Synovium surrounding PCL also supplies the PCL • Contributions inferior medial, inferior lateral genicular arteries via infrapatellar fat pad • Periligamentous and intra-ligamentous plexus • Very little from bony attachment Arnoczky 1987 MOB TCD
    75. 75. Posterior Cruciate Ligament Nerve Supply • Branches of tibial and obturator nerves • Mechanoreceptors • Proprioceptive action MOB TCD
    76. 76. Nerve Supply of Cruciates • • • • Branches of tibial nerve Middle genicular nerve Obturator nerve (post) Branches of the tibial nerve enter via the femoral attachment of each ligament • Nerve fibres are found with the vessels in the intravascular spaces MOB TCD
    77. 77. MOB TCD Mechanoreceptors • • • • • • • • • Three types Found near the femoral attachment Around periphery Superficially, but well below the synovial lining. Where maximum bending occurs Ruffini endings And ones resemble golgi tendon organs Paccinian Proprioceptive function
    78. 78. MOB TCD Mechanoreceptors • Mechanoreceptors resembling golgi tendons • Running parallel to the long axis of the ligament • Found near the femoral attachment • Around the periphery, where maximum bending occurs • Posterior division of obturator nerve
    79. 79. Posterior Cruciate Ligament Bony Attachment • There is a gradual change in stiffness between the flexible ligamentous tissue and bone • There is a transitional zone of fibrocartilage between collagen and bone • This helps to prevent the concentration of stress at the attachment site Beynnon, 2000; Hunziker et al.,1992 MOB TCD
    80. 80. MOB TCD Anatomy of Menisci • Menisci are made of fibro cartilage • Wedge shaped on cross section • Medial is comma shaped with the wide portion posteriorly • Lateral is smaller, two horns closer together round • They are intracapsular and intra synovial anterior
    81. 81. MOB TCD Anatomy of Menisci • Anterior to posterior • Medial, anterior horn is attached to the intercondylar area in front of the ACL and the anterior horn of the lateral meniscus • Posterior horn of lateral, posterior horn of medial and PCL • Medial is more fixed • Lateral more mobile anterior
    82. 82. MOB TCD Anatomy of Menisci • Medial is attached to the deep portion of medial collateral ligament • Lateral is separated from lateral ligament by the inferolateral genicular vessels and nerve • The popliteus, which is attached to lateral meniscus • Posterior horn gives origin to meniscofemoral ligament
    83. 83. MOB TCD Anatomy of Menisci • Coronary ligaments are the portion of the capsule attached to the periphery of meniscus, which connects it to the tibia • Synovial membrane, stops at the upper border of the meniscus • Lines the deep aspect of the coronary ligament
    84. 84. MOB TCD Anatomy of Menisci • Blood supply at the periphery only • Flexion and extension takes place at the upper surface of the menisci • Rotation occurs between the lower surface of the menisci and the tibia anterior
    85. 85. MOB TCD Function of Menisci • • • • • • • • Shock absorption Redistributes forces Spread synovial fluid Minimal effect on stability On rotation menisci move with femur Lateral moves 20 - 24 mm Medial less mobile 10 -15 mm Lateral meniscus bears more load
    86. 86. MOB TCD Meniscofemoral Ligaments • Anterior and posterior arise from posterior horn of lateral meniscus • Anterior attached to femur anterior to PCL • Posterior attached posterior to PCL • More variations in posterior
    87. 87. MOB TCD Meniscofemoral Ligaments • The Anterior meniscofemoral (Humphrey) is attached to lateral aspect of the medial femoral condyle in front of the PCL • The posterior (Wrisberg) is attached posterior to the PCL • The posterior meniscofemoral ligament is usually present • Vary in size
    88. 88. MOB TCD Vessels and Nerves
    89. 89. MOB TCD Articular Fat Pads • • • • • Increase with age Compact lobules With fibro-elastic interlobular septa Septa well vascularised Provide firmness, deformability and elastic recoil Williams & Warick,1980
    90. 90. MOB TCD Infrapatellar Fat Pad (IFP) • Superiorly • Fills the space between the inferior pole of the patella • The ligamentum patella and deep infrapatella bursa • Attached to intercondylar notch via ligamentum mucosum Williams & Warick,1980
    91. 91. MOB TCD Infrapatellar Fat Pad • Posteriorly • Covered by synovial membrane • Forms alar folds • Femoral condyles • Intercondylar notch by ligamentum mucosum • Attached to anterior horns of menisci • Proximal tibia Williams & Warick,1980
    92. 92. MOB TCD Infrapatellar Fat Pad • Blood supply inferior genicular arteries • Also supply the lower part of the ACL from network of synovial membrane of fat pad • Centre of fat pad limited blood supply • Lateral arthroscopic approach to avoid injury Kohn et al., 1995; Eriksson et al., 1980
    93. 93. MOB TCD Infrapatellar Fat Pad • Can only expand anteriorly • Inflammation of IFP • Bulges on either side of patellar tendon • Synovial membrane is compressed by femoral condyles • Pain and inflammation
    94. 94. Clinical Conditions Affecting Infrapatellar Fat Pad • • • • • • • Intrinsic Hoffa’s disease Intracapsular chondroma Localised nodular synovitis Post-arthroscopy / post-surgery fibrosis Shear injury Torsion MOB TCD
    95. 95. Hoffa’s Disease Fat Pad Impingement • Hyperextension injury • Genu recurvatum and tilted inferior pole of patella • Tenderness distal to patella • Beyond margins of the patella Brukner & Khan, 2000; Garret et al., 2000 MOB TCD
    96. 96. Clinical Conditions Affecting IFP • Anterior extra capsular disorders • Patellar fracture • Patellar tendon rupture • Deep infrapatellar bursitis • Patellar tendonosis MOB TCD
    97. 97. Clinical Conditions Affecting IFP Osgood-Schlatter Disease Sinding-Larsen Johanssen Disease MOB TCD
    98. 98. MOB TCD Infrapatellar Fat Pad • ACL repair with patellar tendon may result in fibrosis of fat pad and pain • Delays rehabilitation • Inflammation of IFP may be process leading to fibrosis Murakami et al., 1995
    99. 99. MOB TCD Synovial Membrane
    100. 100. MOB TCD Synovial Membrane • The synovial membrane is very extensive • It lines the inner aspect of the capsule and the nonarticular structures inside the capsule, except posteriorly where it is carried forwards to cover the anterior and sides of the cruciate ligaments
    101. 101. MOB TCD Synovial Membrane • It covers the infrapatellar pad of fat, forming the alar folds • The ligamentum mucosum is attached to the intercondylar notch at the apex of the alar fold • The alar folds increase the surface area of the synovial membrane via the infrapatellar pad of fat, • Which fill the changing spaces during movement of the joint and help to redistribute the synovial fluid
    102. 102. MOB TCD Synovial Membrane • The synovial membrane is continuous with: • The suprapatellar bursa which extends a hand’s breadth above the patella. This bursa always appears distended when there is a haemarthrosis or traumatic synovitis in the knee joint • Many other bursae, e.g. around the popliteus and under the medial head of the gastrocnemius
    103. 103. MOB TCD Plica • A suprapatellar plica may separate the suprapatellar bursa from the synovial membrane of the knee joint • Plicae folds may also be found on either side of the patella
    104. 104. MOB TCD Bursa
    105. 105. MOB TCD Pathological Anatomy of AKP Patellofemoral syndrome Prepatellar bursitis Fractures & Instability Synovial plica Patellar Tendinitis / SLJ Fat pad impingement Infrapatellar Bursitis Traction Apophysitis
    106. 106. Abnormal Lower Limb Biomechanics • • • • • • • Anatomical anomalies Femoral torsion Genu valgum Increased Q-angle High (alta) patella Tibial torsion Overpronation Q Angles Males 140 Females 170 > 200 greater problems MOB TCD
    107. 107. MOB TCD Knee Injuries • • • • • Anterior cruciate tear Bone bruising Posterior cruciate tear Osteochondritis Synovial plica
    108. 108. MOB TCD Knee Injuries Traumatic • Meniscal tears • Ligament tears • Cruciates • Collaterals • Patellar dislocations • Fractures • Patella • Tibial plateau • Articular cartilage damage Atraumatic • Patellofemoral syndrome • Malalignment • Dislocations • Subluxations • Iliotibial band syndrome • Popliteus tendinopathy • Patellar tendinitis • Osgood-Schlatter’s • Fat pad impingement
    109. 109. O’Donoghue’s Triad • Medial ligament tear • Anterior cruciate tear • Torn medial meniscus MOB TCD
    110. 110. MOB TCD Mechanisms of Injury • Valgus / External rotation • Posterior horn of medial meniscus trapped by posterior condyles
    111. 111. MOB TCD Osteochondritis
    112. 112. MOB TCD Meniscal Tears • • • • • Medial meniscus has higher incidence but less morbidity Traumatic tears Twisting on a planted, flexed knee Atraumatic tears Degenerative wear and tear
    113. 113. “BMJ Publishing Group Limited (“BMJ Group”) 2012. All rights reserved.”