derangements of knee

1. Derangements of kneeDr. Zameer Ali

2. Internal derangements of the knee (IDK) It is a term used to cover a group of disorders involving disruption of the normal functioning of the ligaments or cartilages (menisci) of the knee joint.

3. ANATOMY OF KNEE JOINT Bones & Articulations Largest joint in the body Synovial hinge type of a joint Mainly articulation of four bones ;femur, tibia, patella, fibula Each articulation covered with hyaline cartilage; The primary articulation between Condyles of femur & tibia

4. LIGAMENTS Dense structures of connective tissue that fasten bone to bone & stabilise the knee. Inside the knee are two major ligaments-anterior & posterior cruciate ligaments

8. Sprain or tear of the medial collateral ligament.

9. Sprain or tear of the lateral collateral ligament.

10. Partial or complete rupture of the anterior cruciate ligament.

11. Rupture of the posterior cruciate ligament.

12. Tear of the medial semilunar cartilage. This may take the form of a longitudinal spilt (bucket handle tear), or an anterior or posterior horn tear.

13. Tear of the lateral semilunar cartilage. The same variations occur as with a medial cartilage tear.

14. Tear of a degenerate meniscus.

15. Cyst of a semilunar cartilage, usually the lateral.

17. The most frequent cause of damage to the medial collateral ligament is forced valgus injury to the knee Lateral collateral ligament injuries are much less common, as varus stress to the knee occurs much less frequently than valgus stress. Anterior cruciate ligament injury occurs from forced valgus stress to the fully extended knee. Posterior cruciate ligament injury is liable to occur in motor car accidents caused by high velocity trauma, with posterior dislocation of the tibia on a flexed knee, as in a dashboard impact

18. Meniscus tears occur when substantial rotational stresses are applied to the flexed knee. They are particularly common in footballers, when the player is tackled from the side; they are also liable to occur in other sports such as hockey, tennis, badminton, squash and skiing.

19. MEDIAL COLLATERAL LIGAMENT Anatomy: MCL is composed of superficial & deep portions superficial MCL anatomically this is the middle layer of the Medial compartment proximal attachment: posterior aspect of medial femoral condyle. distal attachment: metaphyseal region of the tibia, upto 4-5 cm distal to the joint, lying beneath the pesanserinus

20. function: provides primary restraint to valgus stress at the knee providing from > 60-70% of restraining force depending on knee flexion angle: at 25° of flexion, the MCL provides 78% of the support to valgus stress; at 5° of flexion, it contributes 57% of the support against valgus stress;

21. superficial ligament can be divided into anterior & posterior portions; anterior fibers of superficial portion of ligament appear to tighten with knee flexion of 70 to 105 deg; posterior fibers form the posterior oblique ligament

22. Deep MCL anatomically this is the third (deep) layer of the medial compartment which in many cases will be separated from the superficial MCL (layer II) by a bursa (which allows sliding of the tissues during flexion) divided into meniscofemoral and meniscotibial ligaments inserts directly into edge of tibial plateau & meniscus firmly attaches to the meniscus but does not provide significant resistance to valgus force

23. Examination Findings: valgus stress test clinical findings may be subtle even with complete injury; it is helpful to anchor the thigh on the table with the knee and leg off the edge of the table; opening of 5-8 mm compared to opposite knee may indicate complete tear; determine the point of maximal tenderness to determine whether the tear has occurred proximally, mid-substance, or distally;

24. instability in slight flexion: anterior portion of the medial capsule is primary stabilizer at 30 deg of flexion; hence at 30 flexion, testing is specific for just MCL; instability in extension: posterior portion of the MCL, posterior oblique ligament, ACL, medial portion of posterior capsule & possibly PCL;

27. Operative Treatment: surgical plan depends on whether injury is proximal, mid substance or distal femoral avulsion: with femoral avulsion, it is important to remember that reattachment anterior to its orgin may limit knee flexion where as posterior placement may cause ligament laxity the knee should be held flexed at 30 deg and held in varus when the ligament is reattached

28. Lateral collateral ligament Discussion lateral collateral ligament is primary restraint to varus angulation LCL also acts to resist internal rotation forces cutting of LCL in combination with either anterior or PCL results in large increase in varus opening

29. varus stress test testing with extension: LCL resists approximately 55 % of applied load at full extension cruciate ligaments (primarily ACL) resist approx 25% of moment at full extension significant instability in full extension indicates complete LCL tear as well as a tear of either the ACL or PCL ligament note that LCL instability in extension which occurs with peroneal palsy is a knee dislocation until proven otherwise

30. testing with 30 deg flexion: role of LCL increases with joint flexion, as posterolateral structures become lax with joint flexion,resistance by ACL decreases, but large forces are found in PCL at 90 degrees of flexion LCL is primary restraint to varus stress at 5* & 25*Flexion lateral capsular structure provide secondary support iliotibial band & popliteus muscles have dynamic stabilizing role

32. Main goal is to create a checkrein to external rotation

33. At the level of Gerdy's tubercle, a bone tunnel is created in the posterolateral tibia, just medial to the fibular head

35. Tendinous portion of the graft is then secured in the region of the popliteus insertion with a bone anchor

36. Anchor site should not allow more than 3 mm of motion with knee flexion and extension

38. FUNCTIONS The biomechanical function of the ACL is complex for it provides both mechanical stability & proprioceptive feedback to the knee. In its stabilising role it has four main functions; 1.Restrains anterior translation of tibia. 2.Prevents hyperextention of knee. 3.Acts as a secondary stabiliser to valgus stress, reinforcing medial collateral ligament.

39. contd…. 4.Controls rotation of tibia on the femur in femoral extention of 0-30 degrees. The final role is the main clinical function of ACL.

40. ACL deficiency causes failure of this screw-home mechanism,resulting in subluxation of tibia on the femur. This critical function in the range of 0-30* is important for movements such as side-stepping & pivotting.

42. Blood supply

43. primarily from the middle genicular Artery which pierces the posterior capsule & enters the intercondylar notch near femoral attachment.

44. Additional supply comes from retropatellar pad of fat via the inferior medial & lateral geniculate arteries.

46. The long term outlook for an ACL deficient knee is for the development of significant osteoarthrosis. CAUSES OF ACL RUPTURE 1.Most common cause of ACL rupture is traumatic force applied to the knee in a twisting moment. This can occur with direct or indirect force. 2.Patients with narrow intercondylar notch are more prone to rupture their ACL.

47. 3.Patients with genurecurvatum tend to be more likely to rupture their ACL & are more difficult to treat. 4.Patients with generalisedligamentous disorder. 5.Familial predisposition has been found to play a role in some patients especially those who sustain bilateral ACL tears.

48. Classical history Begins with a non contact deceleration, jumping or cutting action. Other mechanisms of injury include external forces applied to the knee. The patient often describes the knee as having been hyperextended or popping out of the joint & then reducing. A pop is being frequently heard or felt. The patient usually has fallen to the ground & is not immediately able to get up. Resumption of activity is not possible & walking is often difficult. Within a few hours knee swells & aspiration of joint reveals haemarthosis. In this scenario ,the likelihood of ACL injury is greater than 70%.

50. Drawer sign is minimal in isolated ACL rupture. Abnormal displacement >5mm is permitted by loss of restraint by ACL & more so when associated with insufficiency of medial CL or capsular ligament. When an intact PCL is rendered very taut by forcible internal rotation of tibia, it stabilises the knee to the extent that the anterior drawer sign is negated. If internal rotation of tibia does not lessen the anterior drawer sign, the PCL is also insufficient.

51. FALSE NEGATIVE ANTERIOR DRAWER SIGN Especially when the ligamentous Insufficiency is confined to the ACL,the anterior drawer sign is unreliable. With knee flexed to 90 degrees for classical anterior sign, medial meniscus being attached to tibia, abuts against acutely convexed surface of medial femoral condyle & has “door stopper” effect preventing or hindering anterior translation of tibia. With knee extended, relationship is changed. Comparatively flat weight bearing surface of femur does not obstruct forward motion of tibia when anterior stress is applied.

52. LACHMANS TEST One hand secures and stabilises the distal femur while the other hand grasps the proximal tibia. A gentle anterior translation force is applied to the proximal tibia.

53. LACHMANS TEST CONTD… Examiner assesses for a firm/solid or soft endpoint. Stabilisation of right knee during an examination under anaesthesia.

54. Application of anterior tibial translation force with significant ant. translation of the tibia on the femur in an ACL deficient knee. When veiwed from side, a silhoutte of the inferior pole of patella, patellar tendon & proximal tibia shows slight concavity. Disruption of ACL & anterior translation of tibia obliterates the patellar tendon slope.

55. PIVOT SHIFT TEST Patient rotated 20* from supine towards the unaffected side. With slight distal traction on the leg,avalgus & internal rotation force is applied to the extended knee.

56. With maintainance of force noted above,the knee is flexed past 30*

57. Pivot shift in an ACL deficient knee,in the initial stages of knee flexion,the tibia will be anterolaterallysubluxed on the distal femur with application of valgus & internal rotation at the knee.

58. With further flexion of knee(past 30*) the illiotibial band goes from an extendor to flexor of knee & tibialanterolateralsubluxation reduces back in place.

59. Isolated tear produces only small subluxation, greater subluxation occurs when lateral capsular complex or semimembranosus corner also is deficient. DISADVANTAGES: Severe valgus instability may make this test difficult to do because of lack of medial support. FLEXION ROTATION DRAWER TEST Combines anterior drawer & pivot shift test. Mild degree of valgus stress & anterior pressure on upper calf are applied to elicit the positive test.

60. ARTHOSCOPY:Acute complete tear most often found through the midportion & may appear ragged.Less often it is torn at its either end.

61. Roentgenographic studies: Plain roen.often are normal, however,a tibial eminence fracture indicates an avulsion of the tibial attachment of ACL.MRI is the most helpful.

62. MRI FINDINGS: 1.PRIMARY SIGNS: Nonvisualisation Disruption of the substance of ACL by increased abnormal signal intensity Abrupt angulation Wavy appearance Abnormal ACL axis. 2.SECONDARY SIGNS: Segonds fracture osteochondral fracture Anterior translation of tibia Pivot shift Bone bruises.

64. LEFT-Normal ACL in axial plane; RIGHT: Non-visualisation as primary sign of ACL tear with ill-defined edema & haemorhage in the usual location of the ACL in the I/C NOTCH.

65. ACL tear with non-linearity of ligament; mild angulated ACL segonds fracture in a patient with ACL tear.

66. Anterior translation of tibia as a secondary sign of ACL tear. Tangential line to the posterior margin of tibia passes through the posterior horn of lateral Meniscus (uncovered meniscal sign). In normal knee, this line passes posterior to the meniscus.

68. complete tears & no symptoms of knee instability during low demand sports who are willing to give up high demand sports

69. Who do light manual work or live sedentary habits

71. Educate the patient how to prevent knee instability.

73. CHOICE of RX mainly depends on assesment of three patient factors: AGE: The child ,the adolescent, the young adult, the middle aged & the elderly represent different surgical problems. FUNCTIONAL DISABILITY: It may vary from undiagnosed asymptomatic rupture to a patient whose knee gives way on daily basis.

75. Rupture of ACL in the child or elderly is very rare & are usually Rx conservatively.

78. Surgical options Repair of ACL either isolated or with augmentation. Reconstruction with either autograft, allograft or syntheticsp Primary repair of the ACL is no longer recommended because repaired ACL have generally been shown to fall overtime. The torn ACL is generally replaced by a substitute graft made of tendon.The grafts commonly used: PATELLAR TENDON AUTOGRAFT;HAMSTRING TENDON;QUADRICEPS TENDON

81. POSTERIOR CRUCIATE LIGAMENT:ANATOMY Intra-articular but extrasynovial, static stabiliser of knee: composed of two major parts:Large anterior part that forms the bulk of the ligament & a smaller portion that runs obliquely to the back of tibia. PCL is attached proximally to the posterior part of the latral surface of the medial condyle.Thetibial attachment is to a depression behind & below the intra-articular portion of tibia with a slip usually blending with the posterior horn of the latral meniscus.

82. Origin & insertion sites of posterior cruciate ligament:

84. Arthroscopic view of PCL:

85. Biomechanics: Progressive tightening of the PCL occurs during internal rotation of tibia with the knee in either flexion or full extension. Also in full extension the PCL allows only minimal abduction or adduction widening of the knee despite complete removal of accessory supports;the extensor retinaculum, capsular ligaments, collateral ligaments & posterior capsule. This fact emphasis the importance of the PCL as the basic stabiliser of the knee, while the ACL & collateral ligaments augment its stabilising effect.

87. against posterior displacement of tibia in flexed knee,

88. internal rotation of the tibia &

91. Degree of both immediate pain & inability to bear weight on the injured knee is highly variable.

92. These are more pronounced when capsule is intact & haemarthrosis is confined within the joint.

94. tenderness in the poplitealfossa;

95. swelling in allmost all cases.

97. With foot in neutral rotation & stabilised, a firm but gentle posterior translation force is applied to proximal tibia. Initial starting point for a posterior drawer test(foot in NR, knee flexed to 90*)

98. Application of posterior translation force results in posterior subluxation of tibia on the femur in a patient with PCL deficient knee.

99. TIBIAL BACK DROP TESTIn this test, the examiner compares the prominence of the proximal tibiato the femoral condyles with the knee flexed to 80*.In a PCL deficient knee, the knee will be posteriorlysubluxed due to gravity.

100. In a normal knee at 80* the tibial plateau is located approximately 1cm anterior to the femoral condyles

101. TIBIAL BACK DROP TEST IN A PCL DEFICIENT LEFT KNEE NORMAL CONTRALATERAL RIGHT KNEE.

102. QUADRICEPS ACTIVE TEST: It is performed with the knee flexed to 80deg & in neutral rotation.Its starting point is in effect the tibial drop back test.

104. Contraction of the quadriceps muscle in a knee with a PCL deficiency results in an anterior shift of >2mm.

106. Stress radiography assists in the diagnosis of PCL injuries.

107. Increased posterior translation of 8mm or more in stress roeng.is indication of complete rupture.

108. A contrast arthogram may reveal evidence of ligament disruption.

110. TREATMENT OF PCL INJURIES: NON-OPERATIVE TREATMENT: The quoted criteria for non-operative RX include: (1).A posterior drawer test of < 10mm with the tibia in neutral rotation(posterior drawer excursion decreases with internal rotation of tibia on femur). (2). < 5* of abnormal rotatory laxity(specifically, abnormal external rotation of the tibia with the knee flexed 30*,indicating posterolateral instability). (3).No significant valgus-varus abnormal laxity.

111. OPERATIVE TREATMENT Reconstruction is usually delayed for 1 to 2 weeks after injury to allow painful intra-articular reaction to subside & to allow the patient to regain full motion and some strength. Clinically, isolated acute PCL disruptions are repaired if the ligament is avulsed with a fragment of bone. Knee is examined arthroscopically before any open surgical procedure.

112. RX alogrithm for PCL avulsion fracture:

113. Screw reattachment of bone fragment avulsed with PCL from posterior tibia.

114. RECONSTRUCTION OF PCL:Can be done by open or Arthroscopic technique;arthroscopic technique is prefered. Various grafts used are : (1).Patellar tendon graft. (2).Bone-patellar tendon-bone graft. (3).Tendo-achillis bone graft. (4).Illiotibial band. (5).Medial head of gastrocnemius tendon. (6).Hamstring tendon. (7).Lateral meniscus.

115. Treatment alogrithm for PCL injuries:

116. COMPLICATIONS OF PCL RECONSTRUCTION Loss of motion is the most common complication aside from from usual postoperative complication. Flexion loss is more common than extension loss. Failure to obtain objective stability is another common complication. Failure of reconstruction may be the result of untreated associated ligamentous injuries such as the posterolateral corner, which allow excessive forces to be applied to the graft.

118. Vascular complicatons include laceration, thrombosis,& intimal injury to the poplitealartery.Viewing the tip of reamer & guide pin at all times can prevent this injury.

123. At birth the entire meniscus is vascular.

126. History Most meniscal injuries can be diagnosed by obtaining a detailed history.

127. Mechanism of injury Meniscus tears are sometimes related to trauma;but significant trauma is not necessary. A sudden twist or repeated squatting can tear the meniscus. Meniscus tears typically occur as a result of twisting or change of position of the weight-bearing knee in varying degrees of flexion or extension.

129. Mechanical complaints: Descriptions by patients are often nonspecific but include reports of clicking, catching, locking, pinching or a sensation of giving way.

130. Swelling usually occurs as a delayed symptom or may not occur at all. Immediate swelling indicates a tear in the peripheral vascular aspect.

133. Effusion occurs in approximately 50% of the patients presenting with a meniscus tear.

134. The presence of an effusion is suggestive of a peripheral tear in the vascular or red zone (especially when acute),an associated intra-articular injury, or synovitis.

135. Range of motion

136. A mechanical block to motion or frank locking can occur with displaced tears.

138. The medial meniscus is evaluated by extending the fully flexed knee with the foot/tibia internally rotated while a varus stress is applied.

139. The lateral meniscus is evaluated by extending the knee from the fully flexed position, with the foot/tibia externally rotated while a valgus stress is applied to the knee.

142. Anterior Cruciate Ligament Injury

143. Medial Synovial Plica Irritation

144. Contusions

145. Patellofemoral Joint Syndromes

146. Iliotibial Band Syndrome

147. Pes Anserine Bursitis

148. Knee OsteochondritisDissecans

149. Posterior Cruciate Ligament Injury

150. Lateral Collateral Knee Ligament Injury

151. LumbosacralRadiculopathy

152. Medial Collateral Knee Ligament Injury

153. Articular cartilage pathology including arthritis

154. Crystalline deposition diseases including gout and pseudogout (chondrocalcinosis)

156. Arthrography: Historically, arthrography was the standard imaging study for meniscal tears but it has been replaced now by MRI.

158. Acute Phase Rehabilitation Program Physical Therapy

160. The physical therapy program goals are to minimize the effusion, normalize gait, normalize pain-free range of motion, prevent muscular atrophy, maintain proprioception and maintain cardiovascular fitness. Choosing this course of treatment must include consideration of the patient's age, activity level, duration of symptoms, type of meniscus tear, and associated injuries such as ligamentous pathology

162. The natural history of a short (<1 cm), vascular, longitudinal tear is often one of healing or resolution of symptoms.

165. If the patient cannot risk the delay of a potentially unsuccessful period of observation.

166. In cases of a locked knee.

167. Principle of meniscus surgery is to save the meniscus.

168. Tears with a high probability of healing with surgical intervention are repaired.

171. Specific indications and long-term results have not yet been clearly established.

173. Rehabilitation Program

174. Physical TherapyPhysical therapy during recovery is directed toward the same goals as those in the acute phase. For partial meniscectomy, patients may return to low-impact or nonimpact workouts such as stationary cycling or straight-leg raising on the first postoperative day and may advance rapidly to preoperative activities

176. Three main issues are considered in the rehabilitation of meniscus repairs: knee motion, weight bearing, and return to sports.

179. Reported complication rates for meniscus repairs range from 1-30%.

180. The list of complications is the same as that for meniscectomies, with a greater concern for neurovascular injury. Additionally, failure to heal or meniscalreinjury can occur.