Knee biomechanic

1. KNEE BIOMECHANICS D r. Pukhrambam Ratan khuman (PT) M.P.T., (Ortho & Sports)

2. introduction Participating bones – Femur Tibia Patella 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 2

3. Knee complex Tibio -femoral joint Patello -femoral joint 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 3

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 Translations 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 4

5. Knee degree of freedom Rotations Flex/Ext – 15 – 140 Varus /Valgus – 6 – 8 in extension Int / ext rotation – 25 – 30 in flexion Translations AP 5 - 10mm Compression/Distraction 2 - 5mm Medial/Lateral 1-2mm 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 5

6. General Features of Tibio -femoral Joint Double condyloid knee joint is also referred to as Medial & Lateral Compartments of the knee. Double condyloid joint with 3 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 6

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 . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 7

8. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 8

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 Surface 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 9

10. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 10

11. Tibial articulating surface Asymmetrical medial & lateral tibial condyles constitute the distal articular surface of knee joint. M edial tibial plateau is longer in AP direction than lateral The lateral tibial articular cartilage is thicker than the medial side. T ibial plateau slopes posteriorly approx 7 to 10 M edial & lateral tibial condyles are separated by two bony spines called the Intercondylar Tubercles 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 11

12. 9 o 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 congruency. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 12

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) . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 13

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 14

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) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 15

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 muscle 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 16

17. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 17

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) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 18

19. TF alignment & weight bearing 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 185 – 190 , i.e. 5 – 10 creating Physiological Valgus at knee In bilateral static stance – equal weight distribution on medial & lateral condyle 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 19

20. Deviation in normal force distribution – TF angle > 190 – Genu Valgum – compress lateral condyle TF angle < 180 – 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.) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 20

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 21

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 22

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) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 23

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 compartment 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 24

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 band 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 25

26. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 26

27. MCL Attachment – Origin – medial aspect of medial femoral condyle Insertion – proximal tibia Function – Resist valgus stress force (specially in extended knee) Check lateral rotation of tibia Also restrain anterior displacement of tibia when ACL is absent. MCL 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 27

28. LCL Attachment – Origin – lateral femoral condyle Insertion – posteriorly to head of fibula Function – Resist varus stress force across the knee C heck combined lateral rotation with posterior displacement of tibia in conjunction with tendon of popliteal muscle. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 28

29. Cruciate ligament Cruciate = “Resembling a cross ” in Latin. Located within the joint capsule & are therefore called Intracapsular Ligaments . Cruciate ligament provide stability in sagittal plane The ACL & PCL are centrally located within the capsule but lie outside the synovial cavity. ACL PCL 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 29

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) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 30

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 direction 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 31

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) 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 32

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 33

34. Summary of ACL & PCL attachments – ACL – Runs from anterior tibia to posterior femur PCL – Runs from posterior tibia to anterior femur 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 34

35. Posterior capsular ligament Oblique popliteal ligament Posterior oblique ligament Arcuate ligament: Arcuate ligament lateral branch Arcuate ligament medial branch 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 35

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 distal 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 36

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 distal 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 37

38. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 38 Arcuate Ligament Lateral Branch Medial branch Distal Attachment From posterior aspect of the head of the fibula Proximal Attachment To tendon of popliteus muscle & posterior capsule Into oblique popliteal lig on medial side of joint Function Reinforces the postero-lateral knee joint capsule obliquely on a medial to lateral from proximal to distal

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 39

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 “3 rd Cruciate Ligament of Robert” Function – They may assist PCL in restraining posterior tibial translation Also assist popliteus muscle by checking tibial lateral rotation 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 40

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 tuberosity 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 41

42. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 42

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 force 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 43

44. Flexion & extension Axis – no fixed axis but move through ROM (frontal axis) Plan – sagittal plan ROM of flexion / extension – Flexion – 130 – 140 Extension – 5 – 10 (Consider normal, beyond this termed as G enurecurvatum) In close kinematic chain (OKC) – flexion / extension range is limited by ankle range. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 44

45. Medial / lateral rotation Axis – L ongitudinal / Vertical axis Plan – Transvers plan ROM at 90 knee flexion – Lateral rotation – 0 – 40 Medial rotation – 0 – 30 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 45

46. TF CKC Flexion Early 0 - 25 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 tibia 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 46

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 plateau 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 47

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 48

49. Locking & unlocking (screw home mechanism) 6 April 2011 49 Dr. Ratankhuman M.P.T., (Ortho & Sports)

50. Locking of knee joint CKC femoral extension from 30 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 5 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 femur 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 50

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 51

52. Role of Cruciate Ligaments in Flexion/Extension 6 April 2011 52 Dr. Ratankhuman M.P.T., (Ortho & Sports)

53. TF CKC Flexion: ACL Control At full extension – Angle of ACL inclination greatest Anterior directed component force will eventually Restrain Posterior Femoral Roll 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 53

54. TF CKC Flexion: ACL Control cont… As TF flexion increases – Angle of ACL inclination decreases Anterior directed component force increases sufficient enough to produce Anterior Femoral Slide 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 54

55. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 55 Hyperextension Impact on ACL 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 ACL

56. TF CKC Flexion: PCL Control Angle Of PCL Inclination is greatest at full flexion . Anterior directed component force will eventually Restrain Posterior Femoral Roll 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 56

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 Slide 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 57

58. TF OKC Extension Arthrokinematics sagittal plan Extension – Meniscal migrate Anteriorly – Because of meniso -patellar ligament 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 58 Menisco -patellar Ligaments

59. TF OKC flexion Arthrokinematics sagittal plan Flexion – Menisci migrate posteriorly because of Semimembranosis attachment to medial meniscus Popliteus attachment to lateral meniscus 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 59

60. Knee axial rotation 6 April 2011 60 Dr. Ratankhuman M.P.T., (Ortho & Sports)

61. Axial rotation of knee arthrokinemetic 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 61

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 62

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 63

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 insufficiency 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 64

65. Patello-femoral joint (pfj) 6 April 2011 65 Dr. Ratankhuman M.P.T., (Ortho & Sports)

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 66

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. T he 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 2 nd ridge separating medial facet from the extreme medial edge known as Odd Facet of Patella . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 67

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 68

69. PFJ congruence T he 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 69

70. At 10 – 20 of flexion – contact with inferior margin of medial & lateral facet. By 90 of flexion – all portion of patella contact with femur except the odd facet. Beyond 90 of flexion – medial condyle inter the intercondylar notch & odd facet achieves contact for the first time. At 135 of flexion – contact is on lateral & odd facet with medial facet completely out of contact. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 70

71. Patello femoral joint stabilizer 6 April 2011 71 Dr. Ratankhuman M.P.T., (Ortho & Sports)

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 stabilizer 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 72

73. Transvers stabilizer – Medial & lateral retinaculum Vastus Medialis & Lateralis The lateral PF ligament contributes 53% of total force when in full extension of knee. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 73

74. Longitudinal stabilization Patellar tendon – inferiorly Quadriceps tendon – superiorly 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 74

75. Medial-lateral positioning of patella / 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 75

76. Medial & lateral force on patella 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 76

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 77

78. Muscles of knee & its function 6 April 2011 78 Dr. Ratankhuman M.P.T., (Ortho & Sports)

79. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 79 Muscles of the Knee Area One-joint Muscle Two-joint Muscle Anterior Vastus Lateralis Rectus Femoris vastus Medialis Vastus Intermedialis Posterior Biceps Femoris ( Short) Biceps Femoris (Long) Semimembranosus Semitendinosus Sartorius Gracilis Gastrocnemius Lateral   Tensor Fascia Latae

80. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 80 Muscles of Posterior Knee Knee Flexors Semimembranosus, Semitendinosus, Biceps Femoris (Long & Short Heads), Sartorius, Gracilis, Popliteus & Gastrocnemius Muscles Flex + Tibial Medial Rotators Popliteus, Gracilis, Sartorius, Semimembranosus & Semitendinosus Muscles Flex + Tibial Lateral Rotator Biceps Femoris Flex + Abductor Biceps Femoris, Lateral Head Gastrocnemius & Popliteus Flex + Adductor Semimembranosus , Semitendinosus , Medial Head Gastrocnemius , Sartorius & Gracilis

81. Muscles 6 April 2011 81 Dr. Ratankhuman M.P.T., (Ortho & Sports) posterior thigh

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 . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 82

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 moments 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 83

84. biceps femoris or Lateral Hamstring Proximal attachments: By two heads: L ong head – to the tuberosity of ischium , having a common tendon of attachment with semitendinosus. S hort 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 . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 84

85. Semitendinosus or medial hamstring 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 85

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 86

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 calcaneus 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 87

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 88

89. Muscle passing medial knee 6 April 2011 89 Dr. Ratankhuman M.P.T., (Ortho & Sports)

90. Anterior Muscles Quadriceps muscles comprise 4 muscles that cross the anterior knee Rectus femoris Vastus lateralis Vastus Intermedialis Vastus Medialis 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 90

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 35 Lateral to long axis of femur Vastus I ntermedius – P ull Parallel to Shaft of femur, making purest knee extensor. Vastus M edialis – P ull depended on segment of muscle – U pper fibers Vastus Medialis Longus (VML ) angled 15 – 18 Medially Distal fibers Vastus Medialis Oblique (VMO) angled 50 – 55 Medially 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 91

92. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 92

93. Patellar Influence on Quadriceps 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 restraint 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 93

94. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 94

95. Quadriceps activities During 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 95

96. LOG & Movement arm (MA) during squatting 6 April 2011 96 Dr. Ratankhuman M.P.T., (Ortho & Sports)

97. Quadriceps activities during non–weight-bearing The MA of resistance is minimal when the knee is flexed to 90 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 97

98. LOG & Movement arm (MA) during non-weight bearing 6 April 2011 98 Dr. Ratankhuman M.P.T., (Ortho & Sports)

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 20 and 10 . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 99

100. Quadriceps Strengthening: Weight-Bearing versus Non–Weight-Bearing cont… A Posterior Shear Force was also found during Non–Weight-Bearing Exercise , only between 60 and 101 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 100

101. Other muscles helping knee 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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 101

102. Iliotibial Band or IT tract Proximally – The IT band is from Tensor 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 of lateral retinaculum . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 102 ITB GM TFL

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 103

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. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 104

105. Knee joint stabilizers 6 April 2011 105 Dr. Ratankhuman M.P.T., (Ortho & Sports)

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 compartment 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 106

107. Static stabilizer It include the passive structures, such as – Capsule Ligaments – Meniscopatellar lig , PF lig , MCL & LCL, ACL & PCL , Oblique poplitial & Transverse lig . 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 107

108. Dynamic stabilizer It includes following muscles & oponeuroses – Quadriceps femoris , IT band, Extensor retinaculum, Poplitius , Pes anserinus, Hamstrings and also G astrocnemius 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 108

109. Medial joint stabilizers Structure includes – Medial patellar retinaculum, MCL , Oblique poplitial ligament & PCL 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 109

110. Lateral joint stabilizers The structure included in static & dynamic stabilization of knee – IT band, Biceps femoris, Popliteus , LCL , Meniscofemoral arcuate, ACL & Lateral patellar retinaculum 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 110

111. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 111 Knee Joint Stabilizers Direction Structures Functions A-P/ Hyperextension stabilizers Anterior cruciate ligament Iliotibial band Hamstring muscles Soleus muscle (in weight-bearing) Gluteus maximus muscle (in weight-bearing) Limit anterior tibial (or posterior femoral) translation Posterior cruciate ligament Meniscofemoral ligaments Quadriceps muscle Popliteus muscle Medial & lateral heads of gastrocnemius

112. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 112 Knee Joint Stabilizers Direction Structures Functions Varus/valgus stabilizers Medial collateral ligament Anterior cruciate ligament Posterior cruciate ligament Arcuate ligament Posterior oblique ligament Sartorius muscle Gracilis muscle Semitendinosus muscle Semimembranosus muscle Medial head of gastrocnemius muscle Limits valgus of tibia Lateral collateral ligament Iliotibial band Anterior cruciate ligament Posterior cruciate ligament Arcuate ligament Posterior oblique ligament Biceps femoris muscle Lateral head of gastrocnemius muscle Limit Varus of tibia

113. 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 113 Knee Joint Stabilizers Direction Structures Functions Internal/external rotational stabilizers Anterior cruciate ligament Posterior cruciate ligament Posteromedial capsule Meniscofemoral ligament Biceps femoris Limit medial rotation of tibia Posterolateral capsule Medial collateral ligament Lateral collateral ligament Popliteus muscle Sartorius muscle Gracilis muscle Semitendinosus muscle Semimembranosus muscle Limit lateral rotation of tibia

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, M argareta N ordin 6 April 2011 Dr. Ratankhuman M.P.T., (Ortho & Sports) 114