Knee biomechanic

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Knee biomechanic

  1. 1. Dr. Pukhrambam Ratan khuman (PT) M.P.T., (Ortho & Sports)
  2. 2. introduction Participating bones –  Femur  Tibia  Patella22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 2
  3. 3. Knee complex Tibio-femoral joint Patello-femoral joint22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 3
  4. 4. Tibio-femoral/Knee joint Ginglymus – (Hinge) ?  A freely moving joint in which the bones are so articulated as to allow extensive movement in one plane. Arthodial – (Gliding) ? 6 degrees of freedom  3 Rotations  3 Translations22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 4
  5. 5. Knee degree of freedom Rotations  Flex/Ext – 150 – 1400  Varus/Valgus – 60 – 80 in extension  Int/ext rotation – 250 – 300 in flexion Translations  AP 5 - 10mm  Compression/Distraction 2 - 5mm  Medial/Lateral 1-2mm22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 5
  6. 6. General Features ofTibio-femoral Joint Double condyloid knee joint is also referred to as Medial & Lateral Compartments of the knee. Double condyloid joint with 30 freedom of Angular (Rotatory) motion.  Flexion/Extension – ○ Plane – Sagittal plane ○ Axis – Coronal axis  Medial/lateral (int/ext) rotation – ○ Plane – Transverse plane ○ Axis – Longitudinal axis  Abduction/Adduction – ○ Plane – Frontal plane ○ Axis – Antero-posterior axis.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 6
  7. 7. Femoral articular surface Femur is proximal articular surface of the knee joint with large medial & lateral condyles. Because of obliquity of shaft, the femoral condyles do not lie immediately below the femoral head but are slightly medial to it. The medial condyle extend further distally, so that, despite the angulation of the femur’s shaft, the distal end of the femur remains essentially horizontal.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 7
  8. 8. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 8
  9. 9.  In sagittal plane - Condyles have a convex shape In the frontal plane - Slight convexity The lateral femoral condyle  Shifted anteriorly in relation to medial  Articular surface is shorter  Inferiorly, the lateral condyle appears to be longer Two condyles are separated –  Inferiorly by Intercondylar notch  Anteriorly by an asymmetrical, shallow groove called the Patellar Groove or Surface22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 9
  10. 10. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 10
  11. 11. Tibial articulating surface  Asymmetrical medial & lateral tibial condyles constitute the distal articular surface of knee joint.  Medial tibial plateau is longer in AP direction than lateral  The lateral tibial articular cartilage is thicker than the medial side.  Tibial plateau slopes posteriorly approx 70 to 100  Medial & lateral tibial condyles are separated by two bony spines called the Intercondylar Tubercles22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 11
  12. 12.  The tibial plateaus are predominantly flat, but convexity at anterior & posterior margins Because of this lack of bony stability, accessory joint structures (menisci) are necessary to improve joint 9 o congruency.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 12
  13. 13. Menisci of knee joint 2 asymmetrical fibro cartilaginous joint disk called Menisci are located on tibial plateau. The medial meniscus is a semicircle & the lateral is 4/5 of a ring (Williams, PL, 1995).22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 13
  14. 14.  Both menisci are –  Open towards intercondylar area  Thick peripherally  Thin centrally forming cavities for femoral condyle By increasing congruence, menisci play in reducing friction between the joint segment & serve as shock absorber.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 14
  15. 15. Meniscal attachment Common attachment of medial & lateral –  Intercondylar tubercles of the tibia  Tibial condyle via coronary ligaments  Patella via patellomeniscal or patellofemoral ligament  Transverse ligament between two menisci  Anterior cruciate ligament (ACL)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 15
  16. 16. Meniscal attachment Unique attachment of medial menisci –  Medial collateral ligament (MCL)  Semitendinous muscle Unique attachment of lateral menisci –  Anterior & posterior meniscofemoral ligament  Posterior cruciate ligament (PCL)  Popliteus muscle22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 16
  17. 17. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 17
  18. 18.  Young children whose menisci have ample of blood supply have low incidence of injury In adult, only the peripheral vascularized region is capable of inflammation, repair & remodeling following a tearing injury. Menisci are well innervated with free nerve ending & 3 mechanoreceptors (Ruffine corpuscle, Pacinian corpuscle & Golgi tendon organs)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 18
  19. 19. TF alignment & weightbearing force The anatomic/ longitudinal axis –  Femur – Oblique, directed inferiorly & medially  Tibia – Directed vertically  The femoral & tibial longitudinal axis form an angle medially at the knee joint of 1850 – 1900, i.e. 50 – 100 creating Physiological Valgus at knee In bilateral static stance – equal weight distribution on medial & lateral condyle22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 19
  20. 20.  Deviation in normal force distribution –  TF angle > 1900 – Genu Valgum – compress lateral condyle  TF angle < 1800 – Genu Varum – compress medial condyle Compressive force in dynamic knee joint  2 – 3 time body weight in normal gait  5 – 6 time body weight in activities (like – Running, Stair Climbing etc.)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 20
  21. 21. Knee joint capsule Joint capsule enclose – TF & PF is large lax Outer portion – firmly attached to the inferior aspect of femur & superior portion of tibia. Posterior attachment  Proximally to posterior margins of the femoral condyles and intercondylar notch.  Distally to posterior tibial condyle. Anterior attachment  Superiorly – Patella, tendon of quadriceps muscles  Inferiorly patellar tendon complete the anterior portion of the joint capsule.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 21
  22. 22.  The antero-medial & antero-lateral portions of the capsule, are often separately identified as the medial and lateral patellar retinaculae or together as the extensor retinaculum. The joint capsule is reinforced medially, laterally & posteriorly by capsular ligaments.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 22
  23. 23. Extensor retinaculum 2 layers – superficial & deeper Deeper layer –  Connecting the capsule anteriorly to menisci & tibia via coronary ligament (known as patellomeniscal or patellotibial band) Superficial layer –  Mixed with vastus medialis & lateralis muscle & distal continue to posterior femoral condyle (patellofemoral ligament)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 23
  24. 24. Synovial lining The intricacy of fibrous layer capsule is surpassed by its synovial lining except posteriorly. Synovium adheres to anterior aspect & side to the ACL & PCL. Embryologically, the synovial lining of the knee joint capsule is divided by septa into 3 separate compartment –  Superior patellofemoral compartment  2 separate medial & lateral tibiofemoral compartment22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 24
  25. 25. Ligament of knee joint Collateral ligament  Medial collateral ligament (MCL)  Lateral collateral ligament (LCL) Cruciate ligament  Anterior cruciate ligament (ACL)  Posterior cruciate ligament (PCL) Posterior capsular ligament Meniscofemoral ligament Iliotibial band22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 25
  26. 26. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 26
  27. 27. MCL Attachment –  Origin – medial aspect of medial femoral condyle  Insertion – proximal tibia Function –  Resist valgus stress force (specially in extended knee) MCL  Check lateral rotation of tibia  Also restrain anterior displacement of tibia when ACL is absent.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 27
  28. 28. LCL Attachment –  Origin – lateral femoral condyle  Insertion – posteriorly to head of fibula Function –  Resist varus stress force across the knee  Check combined lateral rotation with posterior displacement of tibia in conjunction with tendon of popliteal muscle.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 28
  29. 29. Cruciate ligament Cruciate = “Resembling a cross” in Latin. Located within the joint capsule & are therefore called Intracapsular PCL Ligaments. ACL Cruciate ligament provide stability in sagittal plane The ACL & PCL are centrally located within the capsule but lie outside the synovial cavity.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 29
  30. 30. ACL Attachment –  Origin – from anterior surface the tibia in the intercondylar area just medial to medial meniscus.  It spans the knee laterally to PCL & runs in a superior & posterior direction  Insertion – to posteriorly on lateral condyle of femur ACL is divided into 2 bands –  Antero-medial band (AMB)  Postero-lateral band (PLB)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 30
  31. 31. Function of acl Primarily –  Check femur from being displaced posteriorly on the tibia  Conversely, the tibia from being displaced anteriorly on femur. It tightens during extension, preventing excessive hyperextension of the knee. ACL carried 87% of load when anterior translatory force was applied to tibia with extended knee. Check tibial medial rotation by twisting around PCL ACL injury is common when knee is in flexed & tibia rotated in either direction22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 31
  32. 32. PCL Attachment –  Origin – from posterior tibia in intercondylar area and runs in a superior and anterior direction on medial side of ACL.  Insertion - to anterior femur on the medial condyle PCL is divided into 2 bands –  Antero-medial band (AMB)  Postero-lateral band (PLB)22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 32
  33. 33. Function of pcl Primarily –  Check femur from being displaced anteriorly on the tibia or  Tibia from being displaced posteriorly on femur. It tightens during flexion & is injured much less frequently than ACL. PCL carry 93% of load when posterior translatory force was applied to tibia with extended knee. PCL play a role in both restraining & producing rotation of the tibia.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 33
  34. 34.  Summary of ACL & PCL attachments –  ACL – Runs from anterior tibia to posterior femur  PCL – Runs from posterior tibia to anterior femur22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 34
  35. 35. Posterior capsular ligament Oblique popliteal ligament Posterior oblique ligament Arcuate ligament:  Arcuate ligament lateral branch  Arcuate ligament medial branch22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 35
  36. 36. Oblique popliteal ligament Attachment –  Origin – The central part of posterior aspect of the joint capsule  Insertion - Posterior medial tibial condyle Function –  Reinforces posteromedial knee joint capsule obliquely on a lateral-to-medial diagonal from proximal to distal22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 36
  37. 37. Posterior oblique ligament Attachment –  Origin – Near the proximal origin of the MCL and adductor tubercle  Insertion – Posteromedial tibia, posterior capsule & posteromedial aspect of the medial meniscus Function –  Reinforces the posteromedial knee joint capsule obliquely on a medial-to-lateral diagonal from proximal to distal22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 37
  38. 38. Arcuate Ligament Lateral Branch Medial branch Distal From posterior aspect of the head of the fibulaAttachment Proximal To tendon of popliteus Into oblique popliteal lig onAttachment muscle & posterior capsule medial side of joint Reinforces the postero-lateral knee joint capsule Function obliquely on a medial to lateral from proximal to distal22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 38
  39. 39. Meniscofemoral ligament (MFl) There are 2 portions of MFL, at least one in 91% of knees & 30% knee having both. MFL are not true ligaments because they attach bone to meniscus, rather than bone to bone.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 39
  40. 40. Meniscofemoral ligament (MFl) Attachment –  Origin – Both originate from posterior horn of lateral meniscus  Insertion – to lateral aspect of medial femoral condyle ○ The “Ligament of Humphry” or “Antero-MFL” is the ligament run anterior to PCL on tibia ○ The “Ligament of Wrisberg” or “Postero-MFL” is the ligament run posterior to PCL, also known as “3rd Cruciate Ligament of Robert” Function –  They may assist PCL in restraining posterior tibial translation  Also assist popliteus muscle by checking tibial lateral rotation22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 40
  41. 41. Bursa associated with knee Pre-patellar bursa –  Located between the skin & anterior surface of patella  They allows free movement of skin over patella during knee flexion & extension Subcutaneous bursa –  Located between patellar ligament & overlying skin Deep infra-patellar bursa –  Located between patellar ligament & tibial tuberosity  Helps in reducing friction between the patellar ligament & tibial tuberosity22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 41
  42. 42. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 42
  43. 43. Function of knee joint Osteokinemetic of knee joint –  Primary motions – ○ Flexion / Extension ○ Medial / Lateral Rotation  Secondary motions – ○ Antero-posterior displacement of femur or tibia ○ Abduction / Adduction through valgus or varus force22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 43
  44. 44. Flexion & extension Axis – no fixed axis but move through ROM (frontal axis) Plan – sagittal plan ROM of flexion / extension –  Flexion – 1300 – 1400  Extension – 50 – 100 (Consider normal, beyond this termed as Genurecurvatum) In close kinematic chain (OKC) – flexion / extension range is limited by ankle range.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 44
  45. 45. Medial / lateral rotation Axis – Longitudinal / Vertical axis Plan – Transvers plan ROM at 900 knee flexion –  Lateral rotation – 00 – 400  Medial rotation – 00 – 30022 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 45
  46. 46. TF CKC Flexion Early 00 - 250 knee flexion –  Posterior rolling of femoral condyles on the tibia As flexion continues –  Posterior Rolling accompanied by simultaneous Anterior glide of femur  Create a pure Spin of femur on the posterior tibia22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 46
  47. 47. TF CKC extension Extension from flexion is a reversal of flexion motion. Early extension –  Anterior rolling of femoral condyles on tibial plateau As extension continues –  Anterior Rolling accompanied by simultaneous Posterior glide of femur  Produce a pure Spin of femoral condyles on tibial plateau22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 47
  48. 48. Tf ock flexion / extension When tibia is flexed on a fixed femur –  The tibia performed Both Posterior Rolling & Gliding on relatively fixed femoral condyles. When tibia is Extended on a fixed femur –  The tibia performed Both Anterior Rolling & Gliding on relatively fixed femoral condyles.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 48
  49. 49. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 49
  50. 50. Locking of knee joint CKC femoral extension from 300 flexion –  Larger medial femoral condyle continue rolling & gliding posteriorly when smaller lateral side stopped.  These result in medial rotation of femur on tibia, seen in last 50 of extension.  The medial rotation of femur at final stage of extension is not voluntary or produce by muscular force, which is referred as “Automatic” or “Terminal Rotation”.  The rotation within the joint bring the joint into a closed packed or Locked position.  The consequences of automatic rotation is also known as “Locking Mechanism” or “Screw Home Mechanism”. OKC – lateral rotation of tibia on fixed femur22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 50
  51. 51. Unlocking of knee joint To initiate flexion, knee must be unlocked. A flexion force will automatically result in lateral rotation of femur  Because the larger medial condyle will move before the shorter lateral condyle.  Popliteus is the primary muscle to unlocked the knee.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 51
  52. 52. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 52
  53. 53. TF CKC Flexion: ACL ControlAt full extension –  Angle of ACL inclination greatest  Anterior directed component force will eventually Restrain Posterior Femoral Roll22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 53
  54. 54. TF CKC Flexion: ACL Controlcont… As TF flexion increases –  Angle of ACL inclination decreases  Anterior directed component force increases sufficient enough to produce Anterior Femoral Slide22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 54
  55. 55. Hyperextension Impact onACL End ROM extension brings the mid- substance of the ACL in contact with the femoral intercondylar shelf (notch of Grant) This contact point acts as a fulcrum to tension load the ACL22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 55
  56. 56. TF CKC Flexion: PCL Control Angle Of PCL Inclination is greatest at full flexion. Anterior directed component force will eventually Restrain Posterior Femoral Roll22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 56
  57. 57. TF CKC Extension: PCL Control As TF extension increases –  Angle Of PCL Inclination decreases  Posterior directed component force increases sufficient enough to Produce Posterior Femoral Slide22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 57
  58. 58. TF OKC Extension Arthrokinematics sagittal plan  Extension –  Meniscal migrate Anteriorly – ○ Because of meniso-patellar ligamentMenisco-patellar Ligaments 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 58
  59. 59. TF OKC flexion Arthrokinematicssagittal plan Flexion – Menisci migrate posteriorly because of  Semimembranosis attachment to medial meniscus  Popliteus attachment to lateral meniscus22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 59
  60. 60. Knee axial rotation22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 60
  61. 61. Axial rotation of kneearthrokinemetic Axis – vertical axis Plan – transvers plan ROM – Maximum range is available at 90 of knee flexion. The magnitude rotation diminishes as the knee approaches both full extension and full flexion. Medial condyle acts as pivot point while the lateral condyles move through a greater arc of motion, regardless of direction of rotation.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 61
  62. 62. rotation of tibia During Tibial lateral rotation on the femur –  Medial tibial condyle moves slightly anteriorly on the relatively fixed medial femoral condyle, whereas lateral tibial condyle moves a larger distance posteriorly. During tibial medial rotation –  Medial tibial condyle moves only slightly posteriorly, whereas the lateral condyle moves anteriorly through a larger arc of motion.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 62
  63. 63.  During both medial and lateral rotation –  The menisci reduce friction & distribute femoral condyle force created on the tibial condyle without restricting the motion.  Meniscus also maintain the relationship of tibia & femoral condyles just as they did in flexion and extension.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 63
  64. 64. Valgus (Abduction)/Varus(Adduction) Axis – Antero-posterior axis Plan – Frontal plane ROM –  8 at full extension  13 with 20 of knee flexion. Excessive frontal plane motion could indicate ligamentous insufficiency22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 64
  65. 65. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 65
  66. 66. pFj function It work primarily as an anatomical pulley It reduce friction between quadriceps tendon & femoral condyle. The ability of patella to perform its function without restricting knee motion depends on its mobility.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 66
  67. 67. PFJ articulating surface The triangular shape patella is a largest sesamoid bone in body is a least congruent joint too. Posterior surface is divided by a vertical ridge into medial & lateral patellar facets. The ridge is located slightly towards the medial facet making smaller medial facet The medial & lateral facet are flat & slightly convex side to side & top to bottom. At least 30% of patella have 2nd ridge separating medial facet from the extreme medial edge known as Odd Facet of Patella.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 67
  68. 68. Femoral articulating surface Patella articulate in femur with intercondylar groove or femoral sulcus on anterior surface of distal femur. Femoral surface are concave side to side & convex top to bottom but lateral facet is more convex then medial surface. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 68
  69. 69. PFJ congruence The vertical position of patella in femoral sulcus is related to length of patellar tendon, approximately 1:1 is (referred to as Insall-Salvati index) An excessive long tendon produce an abnormally high position of patella on femoral sulcus known as patella alta. In neutral or extended knee, the patella has little or no contact with the femoral sulcus beneath.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 69
  70. 70.  At 100 – 200 of flexion – contact with inferior margin of medial & lateral facet. By 900 of flexion – all portion of patella contact with femur except the odd facet. Beyond 900 of flexion – medial condyle inter the intercondylar notch & odd facet achieves contact for the first time. At 1350 of flexion – contact is on lateral & odd facet with medial facet completely out of contact.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 70
  71. 71. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 71
  72. 72. Medial-lateral PFJ stability PFJ is under permanent control of 2 restraining mechanism across each other at right angel.  Transvers group of stabilizer  Longitudinal group of stabilizer22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 72
  73. 73.  Transvers stabilizer –  Medial & lateral retinaculum  Vastus Medialis & Lateralis  The lateral PF ligament contributes 53% of total force when in full extension of knee.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 73
  74. 74. Longitudinal stabilization Patellar tendon – inferiorly Quadriceps tendon – superiorly22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 74
  75. 75. Medial-lateral positioning ofpatella / patellar tracking When the knee is fully extended & relax, the patella should be able to passively displaced medially or laterally not more then one half of patella. Imbalance in passive tension or change in line of pull of dynamic structures will substantially influence the patella. Abnormal force may influence the excursion of patella even in its more secure location within intercondylar notch in flexion.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 75
  76. 76. Medial & lateral force onpatella Since the action line of quadriceps & patellar ligament do not co-inside, patella tend to pulled slightly laterally & increase compression on lateral patellar facets. Larger force on patella may cause it to subluxation or dislocate off the lateral lip of femur. Genu valgum increase the obliquity of femur & oblique the pull of quadriceps.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 76
  77. 77.  Femoral anteversion & tibial torsion creates an increased obliquity in patella predisposing to excessive lateral pressure or to subluxation or dislocation. Excessive tension in lateral retinaculum (or weakness of VMO) may cause the patella to tilt laterally. Insufficient height of lateral lips of femoral sulcus may create patellar subluxation or fully dislocation, even with relatively small lateral force.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 77
  78. 78. Muscles of knee & its function22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 78
  79. 79. Muscles of the Knee Area One-joint Muscle Two-joint Muscle Vastus Lateralis Anterior vastus Medialis Rectus Femoris Vastus Intermedialis Biceps Femoris (Long) Semimembranosus Biceps Femoris Semitendinosus Posterior (Short) Sartorius Gracilis Gastrocnemius Lateral Tensor Fascia Latae22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 79
  80. 80. Muscles of Posterior Knee Semimembranosus, Semitendinosus, BicepsKnee Flexors Femoris (Long & Short Heads), Sartorius, Gracilis, Popliteus & Gastrocnemius MusclesFlex + Tibial Popliteus, Gracilis, Sartorius, SemimembranosusMedial Rotators & Semitendinosus MusclesFlex + Tibial Biceps FemorisLateral RotatorFlex + Biceps Femoris, Lateral Head Gastrocnemius &Abductor PopliteusFlex + Semimembranosus, Semitendinosus, Medial HeadAdductor Gastrocnemius, Sartorius & Gracilis 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 80
  81. 81. p o M s t u t h s e i c r g l i h e o s r22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 81
  82. 82. Knee flexor groups 7 muscles flex the knee [Semimembranosus, Semitendinosus, Biceps Femoris (Long & Short Heads), Sartorius, Gracilis, Popliteus & Gastrocnemius Muscles]. 5 muscles of flexors (Popliteus, Gracilis, Sartorius, Semimembranosus & Semitendinosus Muscles) –  They have the potential to medially rotate the tibia on a fixed femur  Whereas the biceps femoris is capable of rotating the tibia laterally.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 82
  83. 83. Knee flexor groups cont… The lateral muscles (Biceps Femoris, Lateral Head of Gastrocnemius, & Popliteus)  Capable of producing valgus moments at knee The medial muscles (Semimembranosus, Semitendinosus, Medial Head of Gastrocnemius, Sartorius & Gracilis)  Can generate varus moments22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 83
  84. 84. biceps femoris or Lateral Hamstring Proximal attachments: By two heads:  Long head – to the tuberosity of ischium, having a common tendon of attachment with semitendinosus.  Short head – to the lower portion of shaft of femur & to lateral intermuscular septum. Distal attachments:  2 heads unite to be attached to the head of fibula, to the lateral condyle of the tibia & to the fascia of leg. AXN:  Hip extension & external rotation  Knee flexion & external rotation. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 84
  85. 85. Semitendinosus or medialhamstring Proximal attachment:  Tuberosity of ischium, having a common tendon with the long head of the biceps. Distal attachment:  Medial aspect of tibia near the knee joint, distal to the attachment of the gracilis. AXN:  Hip extension and internal rotation  Knee flexion and internal rotation.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 85
  86. 86. semimembranosus Proximal attachment:  Tuberosity of the ischium Distal attachment:  Medial condyle of the tibia. AXN:  Knee flexion and internal rotation  Hip extension and internal rotation.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 86
  87. 87. Gastrocnemius Proximal attachments:  Above the femoral condyles and span the knee joint on the flexor side.  The muscular portion of the gastrocnemius may be seen contracting in resisted flexion of the knee.  Because the gastrocnemius is more important as a plantar flexor of the ankle than as a knee flexor Distal attachments:  To the posterior calcaneus22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 87
  88. 88. Popliteus Proximal attachment:  By a strong tendon from the lateral condyle of the femur.  The muscle fibers take a downward medial course and are attached into proximal posterior portion of body of tibia. Distal attachment:  widespread in a proximal-distal direction, giving the muscle a somewhat triangular shape. AXN:  Medial rotation and flexion of knee.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 88
  89. 89. Muscle passing medial knee22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 89
  90. 90. Anterior Muscles Quadriceps muscles comprise 4 muscles that cross the anterior knee  Rectus femoris  Vastus lateralis  Vastus Intermedialis  Vastus Medialis22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 90
  91. 91. Quadriceps muscle Functions –  Together, the 4 components of quadriceps femoris muscle function to extend the knee.  Rectus femoris being a 2 joint muscle, it also involved in hip flexion along with knee extension. Angle of pull of Quadriceps –  Vastus lateralis – Pull 350 Lateral to long axis of femur  Vastus Intermedius – Pull Parallel to Shaft of femur, making purest knee extensor.  Vastus Medialis – Pull depended on segment of muscle – ○ Upper fibers Vastus Medialis Longus (VML) angled 150 – 180 Medially ○ Distal fibers Vastus Medialis Oblique (VMO) angled 500 – 550 Medially22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 91
  92. 92. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 92
  93. 93. Patellar Influence onQuadriceps Function Patella lengthens the MA of quadriceps by increasing the distance of quadriceps tendon & patellar tendon from the axis of the knee joint. The patella, as an anatomic pulley, deflects the action line of quadriceps away from the joint centre, increasing the angle of pull & enhancing extension torque generation. Pull of quadriceps also creates anterior translation of tibia on femur increasing ACL restraint22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 93
  94. 94. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 94
  95. 95. Quadriceps activitiesDuring weight-bearing When an erect posture is attained –  Minimal activity of quadriceps because the LOG passes just anterior to knee axis results in a gravitational extension torque that maintains the joint in extension. In weight-bearing with the knee slightly flexed –  The LOG pass posterior to knee joint axis  As the gravitational torque tend to promote knee flexion, the activity of quadriceps is necessary to counterbalance the gravitational torque and maintain the knee joint in equilibrium.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 95
  96. 96. LOG & Movement arm (MA)during squatting22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 96
  97. 97. Quadriceps activities duringnon–weight-bearing The MA of resistance is minimal when the knee is flexed to 900 but increases as knee extension progresses. Therefore, greater quadriceps force is required as the knee approaches full extension. The opposite happens during weight-bearing activities.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 97
  98. 98. LOG & Movement arm (MA)during non-weight bearing22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 98
  99. 99. Quadriceps Strengthening:Weight-Bearing versus Non–Weight- Bearing Weight-bearing quadriceps exercises as squat & leg press resulted in a posterior shear force at knee throughout the entire ROM There was No Anterior Shear anywhere in the ROM. In contrast, anterior shear force in a non– weight bearing knee extension exercise maximal anterior shear occurring between 200 and 100.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 99
  100. 100. Quadriceps Strengthening: Weight-Bearing versus Non– Weight-Bearing cont… A Posterior Shear Force was also found during Non–Weight-Bearing Exercise, only between 600 and 1010 of flexion. Weight Bearing Exercises are often prescribed after ACL or PCL injury because of less stressful, more like functional movements & safer than non–weight-bearing exercises.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 100
  101. 101. Other muscles helpingknee extension The actions of the Gluteus Maximus & Soleus Muscles can influence knee motion in weight-bearing. Although they do not cross the knee joint, these muscles are capable of assisting with knee extension.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 101
  102. 102. Iliotibial Band or IT tract Proximally – GM  The IT band is from Tensor TFL Fascia Lata (TFL), Gluteus Maximus & Gluteus Medius muscles. Distally –  Attach to lateral intermuscular septum & inserts into the Anterolateral Tibia (Gerdy’s Tubercle).  IT band also attaches to patella via lateral PF ligament ITB of lateral retinaculum.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 102
  103. 103.  AXN:  Reinforcing anterolateral aspect of knee joint  Assisting ACL in checking posterior femoral or anterior tibial translation when the knee joint is nearly full extension.  With the knee in flexion, the combination of IT band, LCL & popliteal tendon increases the stability of lateral knee.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 103
  104. 104. AXN line for itb In extended knee –  IT band moves anterior to the knee joint axis. In flexed knee –  IT band moves posteriorly over the lateral femoral condyle as the knee is flexed. The IT band, therefore, remains consistently taut, regardless of hip or knee’s position.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 104
  105. 105. 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 105
  106. 106. Stabilization of knee joint Classification of supporting structure of knee –  Functional – ○ Static stabilizer ○ Dynamic stabilizer  Structural – ○ Capsular method ○ Extra-capsular method  Location – ○ Medial joint compartment ○ Lateral joint compartment22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 106
  107. 107. Static stabilizer It include the passive structures, such as –  Capsule  Ligaments – ○ Meniscopatellar lig, ○ PF lig, ○ MCL & LCL, ○ ACL & PCL, ○ Oblique poplitial & ○ Transverse lig.22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 107
  108. 108. Dynamic stabilizer It includes following muscles & oponeuroses –  Quadriceps femoris,  IT band,  Extensor retinaculum,  Poplitius,  Pes anserinus,  Hamstrings and also  Gastrocnemius22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 108
  109. 109. Medial joint stabilizers Structure includes –  Medial patellar retinaculum,  MCL,  Oblique poplitial ligament &  PCL22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 109
  110. 110. Lateral joint stabilizers The structure included in static & dynamic stabilization of knee –  IT band,  Biceps femoris,  Popliteus,  LCL,  Meniscofemoral arcuate,  ACL &  Lateral patellar retinaculum22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 110
  111. 111. Knee Joint StabilizersDirection Structures Functions • Anterior cruciate ligament • Iliotibial band • Hamstring muscles • Soleus muscle (in weight- bearing)A-P/ • Gluteus maximus muscle Limit anterior tibialHyperextension (in weight-bearing) (or posteriorstabilizers • Posterior cruciate ligament femoral) translation • Meniscofemoral ligaments • Quadriceps muscle • Popliteus muscle • Medial & lateral heads of gastrocnemius 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 111
  112. 112. Knee Joint StabilizersDirection Structures Functions • Medial collateral ligament • Anterior cruciate ligament • Posterior cruciate ligament • Arcuate ligament • Posterior oblique ligament Limits valgus of tibia • Sartorius muscle • Gracilis muscle • Semitendinosus muscle Varus/valgus • Semimembranosus muscle stabilizers • Medial head of gastrocnemius muscle • Lateral collateral ligament • Iliotibial band • Anterior cruciate ligament • Posterior cruciate ligament Limit Varus of tibia • Arcuate ligament • Posterior oblique ligament • Biceps femoris muscle • Lateral head of gastrocnemius muscle 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 112
  113. 113. Knee Joint StabilizersDirection Structures Functions • Anterior cruciate ligament • Posterior cruciate ligament Limit medial rotation of • Posteromedial capsule tibia • Meniscofemoral ligament • Biceps femorisInternal/external • Posterolateral capsulerotational stabilizers • Medial collateral ligament • Lateral collateral ligament • Popliteus muscle Limit lateral rotation of • Sartorius muscle tibia • Gracilis muscle Semitendinosus muscle • Semimembranosus muscle 22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 113
  114. 114. References Joint Structure and Function: A Comprehensive Analysis, Fourth Edition, Cynthia C. Norkin, 2005 Joint Structure and Function: A Comprehensive Analysis, Third Edition, Cynthia C. Norkin Clinical Kinesiology and Anatomy, Fourth Edition, Lynn S. Lippert, 2006 Basic Biomechanics of the Musculoskeletal System, third edition, Margareta Nordin22 June 2012 Dr. Ratankhuman M.P.T., (Ortho & Sports) 114

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