1. Posterolateral Rotatory Instability of the Knee Steven A. Seeker, M.D.

2. Objectives  Define posterolateral rotatory instability of the knee  Evolution of the human knee  Anatomy and biomechanics of the posterolateral corner  Clinical presentation and treatment options for acute and chronic instability of the posterolateral corner of the knee

3. Definition  Hughston et al. JBJS 1976  Posterior subluxation of the lateral tibial plateau that can occur with an external rotation torque in knees with pathologic laxity of the posterolateral corner  Symptoms can occur acutely after violent injury or develop insidiously after relatively mild injury

4. Evolution of human knee  Complex anatomy due to evolution  Early on, both the tibia and fibula articulated with the femur  As the human knee evolved, the fibula and attached capsule moved distally

5. Evolution of human knee  The popliteus attachment moved from the fibular head to the femur creating an intra-articular portion  Biceps attachment moved from the capsule and tibia to the fibula

6. Posterolateral corner  “ Dark side of the knee “ Andrews 1988  Varying anatomy and inconsistent terminology of the popliteofibular ligament

7. Anatomy of the posterolateral corner  Three distinct layers

8. Anatomy of the posterolateral corner

9. First layer  Iliotibial tract attaching to the tibia at Gerdy’s tubercle  Biceps femoris attaching to the fibular head

10. Second layer  Quadriceps retinaculum anteriorly  Patellofemoral and patellomeniscal ligaments posteriorly

11. Third layer  Superficial lamina: Lateral collateral ligament Fabellofibular ligament

12. Third layer  Superficial lamina: Lateral collateral ligament Fabellofibular ligament

13. Third layer  Deep lamina: Coronary ligament and popliteal hiatus Popliteus Arcuate ligament Popliteofibular ligament Oblique popliteal ligament

14. Third layer  Deep lamina: Coronary ligament and popliteal hiatus Arcuate ligament Popliteofibular ligament Oblique popliteal ligament

15. Variable anatomy  Seebacher et al. JBJS 1982  35 cadaver knees  Conclusions: arcuate ligament alone in 13% fabellofibular ligament alone in 20% both in 67% no mention of popliteofibular ligament

16. Variable anatomy  Sudasna and Harnsiriwattanagit 1990  Dissection of fifty cadaver knees  Conclusions: “Fibular origin of the popliteus” (Popliteofibular ligament) in 98% Fabellofibular ligament in 68% Arcuate ligament in 24%

17. Variable anatomy  Watanabe et al. arthroscopy 1993  115 cadaver dissections  Conclusions: lateral collateral and popliteus present in all knees “popliteus muscle with origin from the fibular head” (popliteofibular ligament) present in 94% of knees

18. Popliteofibular ligament (PFL)  Oversight in anatomy texts resulted in disappearance of this structure until only recently  Maynard et al. Am J Sports Med 1996 reported on the “rediscovery of the PFL”

19. Popliteofibular ligament (PFL)  This appears to be an important static stabilizer of the posterolateral corner

20. Popliteofibular ligament (PFL)  Maynard et al. Am J Sports Med 1996  Cross sectional area of PFL only slightly less than FCL  Maximal force to failure PFL (425 N) FCL (747 N)

21. Popliteofibular ligament (PFL)  Veltri et al. Am J Sports Med 1996  PFL and popliteus were important in resisting posterior translation, primary varus rotation, and external rotation

22. Blood supply  Popliteal artery  Genicular arteries

23. Review of anatomy  Three layers of the posterolateral corner  First layer are dynamic stabilizers  Second layer relatively unimportant

24. Review of anatomy  Third layer: static stabilizers and most important layer FCL and popliteus are always present PFL present in majority of knees arcuate and fabellofibular ligaments are variable coronary ligaments are very loose to allow for very mobile lateral meniscus

25. Biomechanics

26.  Nielson et al. Arch Orthop Trauma Surg 1984, 1985  Lateral collateral and posterolateral capsule resist varus and external rotation of the tibia  Popliteus resists varus from 0-90 0 and resists external rotation from 20-130 0 of flexion  PLC also is a secondary restraint to posterior translation, but isolated sectioning of the PCL does not affect varus or external rotation

27. Biomechanics  Gollehon et al. JBJS 1987  PCL resists posterior translation  Sectioning of PLC/FCL causes the greatest increase in varus and external rotation at 30 o of flexion  Additional sectioning of PCL causes greater increase in varus and external rotation  ACL/PLC sectioning causes tibial internal rotation and anterior translation to be increased at 30 o and 60 o  ACL or PLC sectioning alone does not increase tibial internal rotation

28. Biomechanics  Markolf et al. JBJS 1993  Sectioning of PLC significantly increases the force on the PCL between 45 o and 90 o of flexion  Sectioning of PLC increases mean force on ACL at all flexion angles

29. Biomechanics  Noyes et al. Am J Sports Med 1993  Sectioning PLC increases lateral tibial plateau posterior translation at 30 o but not at 90 o  Sectioning of PLC and PCL increases posterior subluxation of both plateaus at both 30 o and 90 o

30. Biomechanics  LaPrade et al. Am J Sports Med 1999  Forces in ACL grafts when the posterolateral corner had been sectioned were increased with coupled varus and external rotation at 0 o and 30 o of flexion

31. Biomechanics  Skyhar et al. JBJS 1993  Ten cadaver knees  Combined sectioning of PLC and PCL resulted in significantly more patellofemoral contact force than sectioning of the PCL alone

32. Biomechanics  Summary:  Isolated PCL tear does not increase primary varus or external rotation  Isolated FCL tear causes a mild increase in varus angulation which is greatest at 30 o of flexion  Injury of PLC with intact PCL results in maximal increase of varus, external rotation and posterior translation at 30 o of flexion

33. Biomechanics  Summary:  However, at 90 o, the PCL fibers become tight and exert a secondary constraint on varus and external rotation  PCL and PLC complete injury cause increased varus, external rotation and posterior translation at all flexion angles  Cruciate ligament grafts are at increased risk of failure in knees with posterolateral rotatory instability

34. Examination of the posterolateral corner  History and physical exam special tests  Radiographic evaluation  Magnetic resonance imaging  Arthroscopic evaluation

35. History  Pain in posterolateral knee  Peroneal nerve symptoms?  May have medial or lateral joint line pain  Instability with knee in extension

36. Physical examination  Edema, ecchymosis, induration and tenderness  Full ligament exam and neurovascular exam in all patients  May have standing varus alignment or a varus thrust with walking  May walk a flexed knee due to pain and instability with knee hyperextension

37. Special tests  Posterior drawer  Tibial external rotation (dial) test  Posterolateral external rotation test  Reverse pivot shift test  External rotation recurvatum test

38. Posterior drawer  Performed at 30 o and 90 o  Laxity at 30 o indicates PLC injury  Laxity at 90 o indicates PCL injury  May appear like an ACL injury, but tibia is posterior and ACL endpoint is good

39. Tibial external rotation (dial) test  Performed while prone at 30 o and 90 o  PLC only: increased at 30 o only  PCL only: no side to side difference  PCL and PLC: increased at 30 o and 90 o

40. Posterolateral external rotation test  Performed at 30 o and 90 o with coupled posterior and external rotation force  Similar results to drawer and dial tests

41. Reverse pivot shift test  Sensation of reduction when the flexed, externally rotated tibia knee is extended with a valgus applied force  May be positive in up to 35% of normal knees during EUA  May be PLC or PCL injury

42. External rotation recurvatum test  Elevation of lower extremity by great toe results in hyperextension, varus and external rotation

43. PCL vs. PLC vs. Both

44. Radiographic evaluation  Plain film radiographs may show avulsion fractures, widened lateral joint line Segond fracture (lateral capsular sign may be present)

45. Magnetic resonance imaging  Yu et al. Radiology 1996  T2 weighted coronal oblique MRI give best resolution of PLC  LaPrade et al. Am J Sports Med 2000  Developed protocol for PLC imaging

46. Arthroscopy  Valuable to evaluate popliteus and meniscus, as well as articular surface injuries prior to open repair  “Drive through sign”  Caution: fluid extravasation

47. Grading of injury  Grade 1: no abnormal motion with 0 – 5mm of joint opening, and definite end point  Grade 2: slight to moderate abnormal joint motion with 6 – 10 mm joint opening, and definite end point  Grade 3: markedly abnormal joint motion with greater than 10 mm joint opening, and no endpoint

48. Grading of injury  Kannus Am J Sports Med 1989  23 patients with grade 2 and 3 injuries treated non-operatively  8 year follow-up  11 patients with grade 2 lesions excellent or good knee scores, 9 were asymptomatic, all had residual laxity, no DJD  12 patients with grade 3 lesions fair or poor knee scores, but not all isolated PLC injury, DJD in 6 patients

49. Treatment  Non-operative treatment  Operative treatment 1. Acute injury 2. Chronic instability

50. Non-operative treatment  Isolated posterolateral corner injuries are treated with a hinged knee brace to prevent varus and external rotation  The literature supports non-operative management of all grade 1 and 2 isolated PLC injuries  However, may consider operative management of grade 2 lesion if cruciate reconstruction is planned

51. Operative treatment  Acute injury: Direct repair within 3 weeks to avoid “matted mess” has best outcome +/- augmentation  Chronic instability: Reconstruction

52. Surgical approach  Incision

53. Surgical approach  Internervous plane: between ITB and BF  May osteotomize Gerdy’s tubercle for better visualization  Must see the common peroneal nerve

54. Direct repair  Skin incision often is the only dissection needed in acute injuries  Repair deep structures first, followed by superficial structures

55. Direct repair  May need to augment structures with autograft or allograft if structures are not repairable  Combination of techniques used to repair all structures

56. Order of evaluation / repair  Coronary ligament: evaluate for tears or avulsion from tibia – fix with sutures or anchors  Popliteus and popliteofibular ligaments: fix with anchors or pull-out sutures if avulsed or Kessler sutures if torn  FCL: sutures or anchors  Arcuate and fabellofibular ligaments: variable, but should be repaired if torn or avulsed

57. Reconstruction of chronic instability  Often needed after grade 3 injuries treated non-operatively  Surgical dissection more difficult secondary to scar  Goals: restore function and stability to the knee

58. Special considerations for reconstruction  Alignment: full length x-rays of lower extremity to evaluate  Varus with lateral thrust: HTO prior to reconstruction of posterolateral structures or repair will stretch out

59. High tibial osteotomy  Not like HTO for DJD  Long lateral incision centered over ITB  Gerdy’s tubercle advanced with bone plug  Avoid disruption of proximal tib-fib joint, as this will worsen PLC symptoms

60. High tibial osteotomy  Gerdy’s fixed with 6.5mm screw  Osteotomy fixed with staples  Fibular osteotomy should be performed at the mid fibula level  Reassess PLC at 6 months, symptoms may resolve with re- alignment

61. High tibial osteotomy  Alternatively, a medial opening wedge osteotomy of the proximal tibia can be performed  Advantages: avoids the proximal tib / fib joint and posterolateral structures  Disadvantages: 2 surfaces to heal +/- use of allograft or ICBG

62. Posterolateral corner reconstruction

63. Advancement of femoral attachment of FCL and PT Hughston and Jacobson  Advancement of FCL / popliteus and lateral gastroc origin with suturing of FCL to gastroc  96 knees follow-up 4 years 85% objectively good 78% subjectively good 80% functionally good

64. Advancement of femoral attachment of FCL and PT Hughston and Jacobson  Advancement fixed with knee at 90 o  Criticized because it does not address PFL or popliteus musculotendinous junction

65. Advancement of femoral attachment of FCL and PT Hughston and Jacobson  Knee is placed in a controlled motion brace with 45 degree extension block  Flexion is encouraged to prevent patellofemoral problems

66. Biceps tenodesis (Clancy and Sutherland)  Anchor the biceps to the lateral femoral condyle to reduce the deforming force in external rotation and to recreate the FCL  39 patients, average follow-up of 32 months 77% no ADL restriction 54% return to sports

67. Biceps tenodesis (Clancy and Sutherland)  Wascher Am J Sports Med 1993 biomechanical study showed that this was effective, but it overconstrained the joint  Veltri et al. Am J Sports Med 1996 this does not address the popliteus or PFL

68. Biceps tenodesis (Clancy and Sutherland)  Many authors have been reluctant to attempt this because of the difficulty in salvaging the knee if this fails

69. Recession of PT and FCL (Jakob and Warner)  When the popliteus and FCL are stretched, but intact, the femoral attachment may be recessed and fixed by a screw / washer  Advantage is isometric placement

70. Recession of PT and FCL (Jakob and Warner)  If the PFL is intact, this procedure should tighten this structure as well

71. Posterolateral corner sling (Albright and Brown)  Uses autograft or allograft to recreate the static effect of the popliteus  Central third of the ITB is harvested and left attached to Gerdy’s tubercle  Tunnel drilled through lateral tibia to the point of normal popliteus passage on the posterior lateral plateau

72. Posterolateral corner sling (Albright and Brown)  Graft is fixed just proximal to the origin of the FCL  30 patients 8 excellent (no joint pathology) 10 poor (joint pathology or instability) 6 additional procedures  Does not address PFL or FCL

73. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Suggested anatomic reconstruction of all injured / attenuated structures  Popliteus: reconstruct with allograft (achilles) similar to Albright’s procedure fix with suture and buttons or interference screws

74. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Popliteofibular ligament: similar, but tunnel drilled through fibula to recreate origin of PFL ligament fixed to lateral epicondyle just proximal to FCL origin secured with buttons or interference screws

75. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Popliteus and PFL: combine both reconstructions with a single split achilles allograft with bone end of the graft secured to the femur

76. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Popliteus, PFL and FCL: If FCL also requires reconstruction, use distally based segment of the biceps femoris with fixation to the epicondyle with screw and soft tissue washer

77. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Patient is placed in a hinged knee brace to prevent varus and external rotation  Toe touch weight- bearing with brace locked in extension  Allowed motion when NWB

78. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  Bike at 4 weeks  Closed chain at 6 weeks  Jogging at 4 months  Brace worn for 6 months  Return to sports at 6-9 months

79. Anatomic reconstruction of PT and/or PFL and/or FCL (Veltri and Warren)  This technique is relatively new and there are no long term follow-up studies  Promising because of anatomic reconstruction of injured structures

80. Order of repair of the multiply ligamentously injured knee  Most authors at the recent AAOS suggested fixing the PLC prior to ACL or PCL repair  If all three are injured, fix the PLC first at 30 0, followed by the PCL  ACL may be fixed at a later date

81. Review of Posterolateral corner  Anatomy is variable, but the FCL, popliteus and popliteofibular ligaments are present in most knees  Careful physical examination of all ligaments will allow the diagnosis of injury to the PLC  PLC laxity is greatest at 30 o of knee flexion  Arthroscopy and MRI are useful adjuncts to physical exam

82. Review of Posterolateral corner  Grade 1 and 2 isolated lesions can be treated conservatively  Grade 3 lesions should be treated operatively  Early operative intervention has the best chance of a good result  Late reconstruction is a salvage procedure  Prognosis is related to other related pathology (ie. DJD, meniscus tear, etc.)

83. Review of Posterolateral corner  Multiple methods of reconstruction are available  Anatomic reconstruction is a promising new method of reconstruction, but follow-up studies are not yet available