1. Unit 5: Understanding Athletic-Related Injuries to the Lower Extremity
The Knee: Anatomy and Injuries
Sports Medicine
Mr. Smith

2. Knee

3. Mechanics of the Knee Hinge Joint Knee movement
Flexion
Extension
Slight Rotation
Gliding
Knee stability depends on ligaments, joint capsule, and muscles.

4. Joint Capsule

5. Bones of the Knee (Femur)
Medial and lateral condyles
Medial condyle is longer than the lateral condyle.
Trochlea – groove that receives the patella.
Articular cartilage

6. Tibia
Tibial plateau
Tibial plateau has two shallow concavities (facets) that articulate with the medial and lateral condyles.
Tibial tuberosity
Main weight bearing bone (95 – 97%).

7. Tibial Plateau

8. Patella Largest sesamoid bone in the body.
Articulates in the groove between the femoral condyles.
Provides a better line of pull for the quadricep muscles.

9. Patella Tracking

10. Fibula Lateral collateral ligament and muscle attachment.
Non – Weight bearing bone.
Located on lateral aspect.
Minimal knee function.

11. Knee Articulations
Femur and tibia
Femur and patella
Tibia and fibula

12. Ligaments of the Knee

13. Anterior Cruciate Ligament (ACL)
Attachment: femur – intersurface of lateral condyle.
Attachment: Tibia – Anterior tibial plateau.
Prevents excessive anterior movement and internal rotation of the tibia.

14. ACL Extension / Tight Flexion / Relaxed Very vascular
Usually surgically replaced if torn.

15. Posterior Cruciate Ligament (PCL)
Attachment: Femur -Anterior portion of the lateral surface of the medial condyle.
Tibia – Posterior medial tibial plateau.
Prevents excessive posterior movement of the tibia on the femur.
Prevents hyperextension of the knee

16. Medial Collateral Ligament (MCL)
Attachment: Femur – superior epicondyle.
Tibia – Medial aspect / medial meniscus.
Resists valgus forces.
Resists external rotation of the tibia.

17. Lateral Collateral Ligament (LCL)
Attachment: Femur – lateral epicondyle.
Fibula: Fibular head
Extracapsular
Resists varus forces.
Aided by popliteal muscle / IT-band

18. Meniscus

19. Meniscus Medial (C- shape) and lateral (O-shape) meniscus.
Located on tibial plateau.
Primary function – shock absorber.
Deepens articular facets
Increase surface contact.
Helps stabilize knee

20. Meniscus

21. Meniscus 3 vascular zones
Red – Red Zone- outer 1/3 which has good blood supply.
Red – White Zone- middle 1/3 which has minimal blood supply.
White – White Zone- inner 1/3 which is avascular (no blood supply)

22. Bursa's of the Knee Bursa’s are fluid filled sac’s .
Reduce friction between anatomical structures.
Two dozen bursa’s within the knee.
Prepatellar most often injured.

23. Bursa's of the Knee

24. Muscles of the Knee

25. Quadricep Muscle Group

26. Quadriceps Extensors of the knee. Stabilizers of the knee.
Vastus medialis (VMO) – important for patellar tracking.
Vastus intermedialis
Vastus Lateralis
Rectus femoris – Knee extension / Hip flexion.

27. Patellar Tendon
Patellar Tendon – Common tendon for the quadriceps muscle group.
Attachment: Tibial tuberosity.
Houses the patella.

28. Hamstring Muscle Group

29. Hamstrings Flexors of the knee. Extensors of the hip.
Prevents anterior tibial movement / Aids ACL.

30. Other Structures of the Knee

31. Other Structures Con't Gracilis – Aids in knee flexion.
Sartorius – Aids in knee flexion / longest muscle in the body.
Gastrocnemius – Aids in knee flexion / primary ankle plantar flexor.

32. IT - Band Lateral side of knee.
Assist LCL in the lateral stability of the knee.

33. I-T Band Friction

34. Knee Injuries

35. Chondromalcia

36. Meniscus Injuries Mechanism – Compression and rotation femur / tibia.
Can be associated with ligament injury (MCL).

37. Meniscus injuries Signs & Symptoms - Joint effusion (Swelling)
- Clicking or locking.
- Loss of ROM
- Diagnosis is often difficult.

38. Meniscus MRI

39. Meniscus Tear

41. Treatment Surgical treatment
- Procedure depends on location and severity of tear.
- Resection (Total removal of tear)
- Stitch or tack.

42. Tack Repair

44. Non Surgical Treatment
- Indicated only for minor tears.
- RICE (Control Swelling)
- Maintain ROM / Strength
- Non surgical treatment can result in further damage

45. Arthriis
Arthritis

46. ACL Injuries Common in sports.
Mechanism – External rotation of tibia, knee in valgus position, foot fixed.
Signs & Symptoms
Feeling pop
Knee feels unstable
Joint effusion
Positive testing

47. Non Surgical Treatment
RICE (Control Swelling)
Immobilizer / Crutches
Refer to physician
Rehabilitation (Strengthening & ROM)

48. MRI of ACL
NORMAL ACL
ACL TEAR

49. Surgical Treatment Arthroscopic surgery
Various grafts can be used for repair.
Patellar tendon (Autograft)
Hamstring (semitendinosus / Gracillis)
Cadaver (Allograft)
Surgical Treatment

54. Patellar Tendon (autograft)

60. Intercondyler Notch

61. Notch Plasty

62. PCL Injuries Injured less frequent Mechanism:
- Fall on anterior aspect of bent knee with foot plantar flexed.
- Hyperextension

63. PCL MRI

64. PCL Injuries Signs / Symptoms - Experience “Pop” - Effusion (swelling)
- Tenderness posterior aspect of knee
- Knee feels unstable
- Positive special test

65. MCL / LCL Injuries
MCL injuries are usually caused by a lateral to medial blow to the knee. Also known as a valgus force.
LCL injuries are usually caused by medial to lateral blow to the knee. Also known as a varus force.

66. MCL Injuries Mechanism of Injury
- direct blow from the lateral side (Valgus Stress)
- severe rotation of the tibia
- can be a combination of both

67. MRI OF MCL TEAR

68. MCL Sprains 1st degree - ligamentous fibers are stretched
- joint is stable during valgus stress test
- little or no joint effusion
- may be some joint stiffness and medial joint line tenderness
- almost full range of motion

69. MCL Sprains 2nd degree sprain - partial tear of the ligament
- slight to moderate laxity during valgus stress test
- there is little joint effusion
- moderate to severe joint stiffness with loss of ROM

70. MCL Sprains 3rd degree sprain - Complete tear
- severe laxity revealed with valgus stress test
- moderate joint effusion
- loss of ROM

71. Treatment of MCL Sprains
1st degree – RICE, Rehab to increase strength, ROM.
2nd degree – RICE, Immobilize, Crutch, 24 hours. Re-evaluate. Refer to physician
3rd degree – RICE, Immobilize, Crutch. Refer to physician

72. LCL Injuries Not very common in athletics.
Occurs by a medial blow to knee which produces a varus stress

73. Patellar Dislocation

74. Knee Dislocation

75. Knee Dislocation

77. Assessing the Knee Joint

78. HISTORY What did you feel, hear, …. Was there a pop or snap?
Did you get hit by another player? Was your foot planted? Did this happen without being hit?
Exactly where does you knee hurt, and be specific?
Have you hurt this knee before, when, what was the injury?

79. HISTORY When did you first notice the condition?
Is there swelling or recurrent swelling?
What activity hurts the most?
Does it ever catch or lock?
Do you fell as if the knee is going to give way, or has it already done so?
Does it hurt to go up and down stairs?

80. Observation Does the athlete have a limp, or is it easy to walk?
Cant the athlete be full weight bearing?
Is the athlete able to perform a half-squat to extension?
Cant the athlete do up and down stairs?

81. Testing for Knee Joint Instability
Testing helps one get a better idea of the stability of the joint and an informed decision can be made about playing status.
Many tests may point to ligamentous damage, while others will help detect meniscus damage.
Knowing these test and how to perform them takes practice and time to understand the degrees of damage done to the knee.

82. Patellar Apprehension
Test for patellar dislocations
Positive sign is guarding, and pain.

83. McMurray Meniscal Test
Tests for torn meniscus
Positive sign is popping, clicking or pain.
Apley’s Compression/Distraction
- Tests for torn meniscus
- Compression signs same as McMurray
- Distraction sign is reduction of pain.

84. Valgus and Varus Stress Tests
Purpose: intended to reveal laxity of the medial and lateral collaterals.
The athlete lie supine with the leg extended.
Apply stress to the knee either medially or laterally

85. Valgus Stress Tests
The valgus examination in full extension tests the MCL, posteromedial capsule, and the cruciates. The exam at 30 degrees flexion isolates the MCL.

86. Valgus Stress Test Tests for MCL stability
Positive sign indicates an injury to the MCL
Test at 0 and 15 degrees

88. Varus Stress Tests
The examiner reverses hand positions and tests the lateral side with a varus force on the fully extended knee and then with 30 degrees of flexion. With the knee extended, the LCL and posterolateral capsule are examined. At 30 degrees of flexion, the LCL is isolated.

89. Varus Stress Test Tests for LCL stability
Positive sign indicates an injury to the LCL
Test at 0 and 15 degrees

91. Anterior Cruciate Ligament Tests
Anterior Drawer Test
Lachman’s Test

92. Anterior Drawer Test
The tibia’s sliding forward from under the femur is considered a positive anterior drawer sign. If a positive anterior drawer sign occurs, the test should be repeated with the athlete’s leg rotated internally 30 degrees and externally 15 degrees.

93. Special Tests Anterior Drawer Test
- Tests for ACL instability / laxity
Positive sign is increase in anterior translation. (No end point)

97. Anterior Cruciate Ligament Tests
Lachman’s Test: is considered to be a better test than the drawer test at 90 degrees of flexion.

98. Lachman’s Tests
The Lachman’s test is administered by positioning the knee in approximately 30 degrees of flexion. One hand of the examiner stabilizes the leg by grasping the distal end of the thigh, and the other hand grasps the proximal aspect of the tibia and attempts to move it anteriorly. A positive Lachman’s test indicated damage to the ACL

99. Special Tests Lachman Test - Test for ACL instbility/laxity
Positive sign is increased anterior tibial translation. (No end point)

101. Posterior Cruciate Ligament Tests
Posterior Drawer Test: is performed with the knee flexed at 90 degrees and the foot in neutral position. Force is exerted in a posterior direction at the proximal tibial plateau. A positive posterior drawer test indicates damage to the posterior cruciate ligament.

102. Special Tests Posterior Drawer - Test for PCL instability/laxity
Positive sign is posterior movement of the tibia.

104. Posterior Cruciate Ligament Tests
Posterior Sag Test: With the athlete supine, both knees are flexed to 9- degrees. Observing laterally on the injured side, the tibia will appear to sag posteriorly when compared to the opposite extremity if the posterior cruciate ligament is damaged.

106. Special Tests

107. Prevention of Knee Injuries
To avoid injuries to the knee, the athlete must be as highly conditioned as possible, which means total body conditioning that includes strength, flexibility, cardiovascular and muscle endurance, agility, speed and balance.
THE MUSCLES around the knee MUST be strong and flexible.

108. Prevention of Knee Injuries
Athletes participating in a particular sport should acquire a strength ratio between the quadriceps and hamstring muscle groups. Fro example: the hamstring muscles of football players should have 60 to 70 percent of the strength of the quadriceps muscles. The gastrocnemius muscle should also be strengthened to help stabilize the knee. Although maximizing muscle strength may prevent some injuries, it fails to prevent rotary-type injuries.

109. Prevention of Knee Injuries
Shoe Type:
Cleat Length
Astro Turf shoes: more grip=more injuries
Sneakers are good for artificial surfaces

110. Functional and Prophylactic Knee Braces
Functional Knee Braces are used to protect grade 1 and 2 sprains of the ACL and MCL, and reconstructed ACL knees. Most of them are bilateral knee braces, meaning there is a hinge on both sides of the brace. These braces have an important part within the athletic community. They will also give the athlete confidence while playing.

112. Functional and Prophylactic Knee Braces
Prophylactic Knee Braces are designed to prevent or reduce the severity of knee injuries. They are worn on the lateral surface of the knee to protect the medial collateral ligament.

115. Knee Injury Treatments
Straight Leg Raises

116. Knee Injury Treatments
Side Leg Raises

117. Knee Injury Treatments
Side Leg Raises

118. Knee Injury Treatments
Terminal Knee Extensions

119. Knee Injury Treatments
Step Ups

120. BOSU