1. KNEE
Chapter 13

2. THE KNEE
The knee is considered one of the most complex joints in the human body.

3. Sports place extreme stress on the knee, therefore it is also one of the most traumatized joints.

4. The knee is considered a HINGE JOINT
- performs two principle actions: FLEXION and EXTENSION.
Medial and Lateral rotation of the tibia are also possible.
When in a flexed position only

6. The bony arrangement of the knee is extremely weak
Support is provided by ligaments and muscles.
The knee is designed primarily to provide stability in weight bearing and mobility in locomotion.

7. KNEE ANATOMY
BONES:
Femur:
- Longest bone in the human body.

8. Tibia:
- Weight Bearing
bone in the lower leg.
Fibula:
- Attachment for ligaments and muscles in the lower leg.

9. Patella - It is a floating bone, embedded in the patellar tendon.
- Is the largest sesamoid bone in the human body.
- It is a floating bone, embedded in the patellar tendon.
- It serves to protect the anterior aspect of the knee.

10. ARTICULATIONS:
The articular surfaces of the bones that make up the knee are covered by HYALINE CARTILAGE - a smooth and pearly substance that reduces friction.

11. The knee joint consists of several articulations, including:
1. Tibiofemoral Joint
(where tibia and femur connect)
- Primary movement occurs here

12. Patellofemoral Joint
as the knee flexes and extends, the patella glides up and down in the femoral grove (on the anterior aspect of the femur

13. MENISCI (singular:Meniscus)
Are located between the femur and the tibia
Are thick pieces of fibrocartilage that act as shock absorbers in walking, running, and jumping

14. The menisci help to stabilize the knee, especially when the knee is flexed at 90 degrees.
Generally the meniscus has a poor blood supply, which means that it does not heal well when injured.

15. LIGAMENTS:
~ There are 4 major ligaments in the knee

16. Ligaments
Anterior Cruciate
Ligament (ACL)
Posterior Cruciate Ligament (PCL)
Medial Collateral Ligament (MCL)
Lateral Collateral Ligament (LCL)

17. Anterior Cruciate Ligament (ACL)
- It prevents the femur from moving posteriorly during weight bearing.
- It works in conjunction with the hamstring muscles
meniscus

18. Posterior Cruciate Ligament (PCL):
Prevents:
hyperextension of the knee
femur from sliding forward during weight bearing.

19. Medial Collateral Ligament (MCL):
Is a wide and flat band of tissue
The MCL has a Superficial and Deep layer.

20. Lateral Collateral Ligament:
Is a round fibrous cord shaped like a pencil.

21. meniscus

22. MUSCLES
Muscles of the knee provide both, MOVEMENT and STABILITY
A number of muscles must work together in a highly complex fashion.

23. FLEXION Hamstring Group: - Semimembranosus - Semitendinosus
- Biceps Femoris
Posterior thigh

24. EXTENSION Quadriceps Group: - Vastus Medialis, Vastus Lateralis
- Rectus Femoris (also does Hip Flexion)
- Vastus Intermedius (underneath Rectus femoris)

25. ROTATION :
Is limited and can occur only when the knee is in a flexed position.
Is performed primarily by the hamstring muscles.

26. PREVENTION Preventing knee injuries in sports is a complex problem.
It is important :
to be in good physical condition
Rehabilitate all injuries
Wear appropriate shoes and
Protective/ preventative bracing

27. KNEE INJURIES

28. 5. Posteriorly Directed Force 6. Anteriorly Directed Force
SIX MECHANISMS of INJURY:
1. Valgus Stress
2. Varus Stress
3. Internal Rotation
4. External Rotation
5. Posteriorly Directed Force
6. Anteriorly Directed Force 1 2 5 3 4 6

29. Three Degrees of Injury - Signs & Symptoms
First Degree – Mild to No swelling, pain, ecchymosis, laxity
Second Degree – Moderate to
mild swelling, pain, ecchymosis, laxity
Third Degree – Moderate to Severe swelling, pain, ecchymosis,
laxity

30. 1. MEDIAL COLLATERAL LIGAMENT SPRAIN:
Most MCL injuries result from a Valgus Stress
(being hit on the outside of the knee, transferring the force to the inside – Contracoup)

31. Concern: often the capsule and the Medial Meniscus are also damaged with this type of injury.
Can also present a false positive on Valgus Stress Test

32. Special Test Valgus Stress Test Laxity of Medial Collateral Ligament
Patient: lies supine with leg extended and relaxed
AT: standing lateral to the patients leg; one hand holds medial aspect of ankle while the heel of the other hand is place on the center of the lateral aspect of the knee. Apply force inward on the knee
Fully extended – MCL, Cruciates, capsule
30 degrees of flexion – isolates MCL
Positive – excessive movement, pain

33. 2. LATERAL COLLATERAL LIGAMENT SPRAIN:
Most injuries to the LCL are from a Varus Force, often with Internal Rotation.
Skier who is “snowplowing”.
An Avulsion Fracture (Fibula) can occur.

34. Three Degrees of Injury Signs and Symptoms
Very similar to MCL sprain, just on lateral aspect of leg
Unlike the MCL the LCL does not have the ability to heal itself; therefore a 2nd and 3rd degree sprain requires surgical intervention

35. Varus Stress Laxity of Lateral Collateral Ligament
Patient: lies supine with leg extended and relaxed
AT: standing medial to the patients leg; one hand holds lateral aspect of ankle while the heel of the other hand is place on the center of the medial aspect of the knee. Apply force outward on the knee
Fully extended – LCL, capsule
30 degrees of flexion – isolates LCL
Positive – excessive movement, pain

36. 3. ANTERIOR CRUCIATE LIGAMENT SPRAINS
Comprised of three twisted bands
The most common and most seriously disrupted ligament in the knee.
Mechanisms of injury include:
- deceleration with a sudden cutting motion.

37. Hyperextension
Prevents femur from moving posteriorly during weight bearing
Excessive hyperextension can also tear the ACL.

38. Signs and Symptoms
Pain, swelling (sometimes delayed), sliding/giving way when weight bearing, inability/lack of desire to weight bear
Positive Special Test
Anterior Drawer
Lachman

39. Treatment for ACL Sprains:
~ Knee immobilizer
~ Crutches
~ PRICE
~ A 2nd and 3rd degree ACL sprain usually requires reconstructive surgery, followed by about months of rehabilitation

40. ACL Injuries
Torn ACL
Reconstructed ACL

41. ACL Reconstruction

45. Anterior Drawer Laxity of Anterior Cruciate Ligament
Patient: lies supine with knee flexed to 90 degrees and relaxed
AT: sitting on the toes. Thumbs on the tibial tubercle, fingers wrap around to posterior aspect just below joint line. Apply reverse force (pull). Foot is then rotated medially and repeat. Foot is then rotated laterally and repeat.
Positive – excessive movement, pain F

46. 4. POSTERIOR CRUCIATE LIGAMENT SPRAIN
Mechanisms of injury include:
- A fall or being hit on the anterior aspect of a flexed knee.
- Hyperflexion

47. Three Degrees of Injury
Signs and Symptoms
- Similar to ACL sprains, surprisingly there is often very limited swelling with PCL injuries

48. Treatment for PCL Sprains:
Crutches
Knee immobilizer
PRICE
Whether or not a torn PCL will be reconstructed depends on the team physician‘s philosophy

49. Usually athletes are very functional with a torn PCL
after symptoms have subsided
the knee has been properly rehabilitated
Proper bracing is applied

50. Posterior Drawer Laxity of Posterior Cruciate Ligament
Patient: lies supine with knee flexed to 90 degrees and relaxed
AT: standing facing patient. Thumbs on the tibial tubercle, fingers wrap around to posterior aspect just below joint line. Apply force posteriorly (push – towards gluteus muscles)
Posterior Drawer
Positive – excessive movement, pain
Fdgs

51. Godfrey’s (Posterior Sag)
Laxity of Posterior Cruciate Ligament
Patient: lies supine with both knees flexed to 90 degrees and relaxed
AT: standing at patients involved side. Grasp ankles with one hand, control legs with the other. Keeping knees flexed to 90 degrees, flex hips to 90 degrees.
Positive – divot appears (tibia sags posteriorly) just inferior to patella on joint line of involved leg.

52. Lachman Laxity of Anterior Cruciate Ligament and Posterior
Patient: lies supine with knee flexed to 30 degrees and relaxed
AT: standing at the patients side. One hand grasps the distal upper leg, the other hand grasps the proximal lower leg (both with thumbs no the anterior aspect). Anterior force is applied to the tibia
Positive – excessive movement, pain

53. MENISCAL INJURIES:
The medial meniscus has a higher incidence of injury than the lateral meniscus.
This is due to its attachment to the MCL

54. MENISCAL INJURIES
The menisci can easily be injured by twisting motions, hyperextension, or hyperflexion of the knee

55. People tear their menisci when simply getting out of a car
It is not unusual to injure a meniscus along with ligamentous damage

56. Signs and Symptoms: Severe Pain and Loss of Motion
Possible locking or giving way of the Knee Joint
Swelling usually does not set in until 24 to 48 hours after injury (due to limited blood supply)

57. Treatmen for Meniscal Lesions:
PRICE
Knee immobilizer
Crutches

58. McMurray’s Meniscal Injuries Patient: lies supine relaxed
Meniscal Injuries
Patient: lies supine relaxed
AT: holds joint line at knee and heel; flexes and extends knee and hip while rotating in a figure 8 fashion
Positive: Pain and/or clicking on joint line

59. Apley Distraction & Compression
Laxity of Ligament/Meniscus
Performed when positive Valgus,Varus, or McMurray’s
Patient: lies prone with legs straight and relaxed
AT: standing at patients involved side. Flexes patients involved knee to 90 degrees. Stabilize upper leg with ATs lower leg. Apply traction to knee (pull up on ankle – towards ceiling) and rotate lower leg.
Positive
pain = capsule or ligament
No pain = meniscus

60. Unhappy Triad
When the following three structures, ACL, MCL, and Medial Meniscus are involved in an injury, it is referred to as the “unhappy triad”

61. S & S / Treatment S&S – same as ACL and Menisci in one Treatment
Knee immobilizer
Price
Physician Referral immediately
911 if suspect nerve or blood vessel damage

62. Knee Dislocation
Possible tear of all ligaments, meniscus, blood vessels, and nerves
S & S – obvious deformity, pain
Treatment – stabilize as found and call 911!

63. PATELLA CONDITIONS

64. 1. PATELLAR FRACTURES:
Direct or Indirect Trauma
SIGNS AND SYMPTOMS:
pain and point tenderness
Swelling
Loss of function
Treatment:
PRICE, splint, & get to team physician

66. 2. LUXATION ( Dislocation):
Signs and Symptoms
Patella is sitting on the lateral side of the femur
Pain & distress
Treatment
Splint in the position found call 911

68. 3. CHONDROMALACIA
Is a softening and deterioration of the articular cartilage on the back of the patella.
Usually associated with patellar tracking problems.

70. Signs and Symptoms:
Pain with activity and/or ascending/decending stairs.
Swelling around the patella.
Grating Sensation (like 2 pieces of sandpaper rubbing on each other).

71. Treatment Avoid irritating activities
Orthotics to correct pronation of feet and to reduce tibial torsion
Anti-inflammatory medications
Neoprene knee sleeve

72. Constant pulling at the bone may result in an avulsion fracture.
4. OSGOOD-SCHLATTER DISEASE:
Characterized by pain at the attachment of the patellar tendon to the tibial tubercle.
Constant pulling at the bone may result in an avulsion fracture.
Occurs during adolescence.

74. Repeated irritation causes swelling.
Signs and Symptoms:
Repeated irritation causes swelling.
Gradual degeneration of the epiphysis (growth plate).
Severe pain when kneeling, running, and jumping.
Point tenderness at tibial tubercle
Deformity at the Tibial Tubercle.

76. Osgood-Schlatter Disease
Treatment
Reduce Stress on the Knee
Ice before and after activity
Strengthen Quadriceps and Hamstrings
Taping

77. Also called Jumper‘s Knee
5. PATELLAR TENDINITIS:
Also called Jumper‘s Knee
Sudden or repetitive forceful extension of the knee may begin an inflammatory process that will eventually lead to tendon degeneration.

78. Signs and Symptoms: Three Stages of Tendinitis:
Stage 1 - Pain after activity
Stage 2 - Pain during & after activity
Stage 3 - Pain during activity and prolonged after activity

79. Treatment: Heat before activity Ice after activity
Cross-friction massage
Stretching
Taping or Bracing

80. Knee
Special Tests

81. Special Test Valgus Stress Test Laxity of Medial Collateral Ligament
Patient: lies supine with leg extended and relaxed
Practitioner: standing lateral to the patients leg; one hand holds medial aspect of ankle while the heel of the other hand is place on the center of the lateral aspect of the knee. Apply force inward on the knee
Fully extended – MCL, Cruciates, capsule
30 degrees of flexion – isolates MCL
Positive – excessive movement, pain

82. Varus Stress Laxity of Lateral Collateral Ligament
Patient: lies supine with leg extended and relaxed
Practitioner: standing medial to the patients leg; one hand holds lateral aspect of ankle while the heel of the other hand is place on the center of the medial aspect of the knee. Apply force outward on the knee
Fully extended – LCL, capsule
30 degrees of flexion – isolates LCL
Positive – excessive movement, pain

83. Anterior Drawer Laxity of Anterior Cruciate Ligament
Patient: lies supine with knee flexed to 90 degrees and relaxed
Practitioner: sitting on the toes. Thumbs on the tibial tubercle, fingers wrap around to posterior aspect just below joint line. Apply reverse force (pull). Foot is then rotated medially and repeat. Foot is then rotated laterally and repeat.
Positive – excessive movement, pain F

84. Posterior Drawer Laxity of Posterior Cruciate Ligament
Patient: lies supine with knee flexed to 90 degrees and relaxed
Practitioner: standing facing patient. Thumbs on the tibial tubercle, fingers wrap around to posterior aspect just below joint line. Apply force posteriorly (push – towards gluteus muscles)
Posterior Drawer
Positive – excessive movement, pain
Fdgs

85. Godfrey’s (Posterior Sag)
Laxity of Posterior Cruciate Ligament
Patient: lies supine with both knees flexed to 90 degrees and relaxed
Practitioner: standing at patients involved side. Grasp ankles with one hand, control legs with the other. Keeping knees flexed to 90 degrees, flex hips to 90 degrees.
Positive – divot appears (tibia sags posteriorly) just inferior to patella on joint line of involved leg.

86. McMurray’s Meniscal Injuries Patient: lies supine relaxed
Meniscal Injuries
Patient: lies supine relaxed
Practitioner: holds joint line at knee and heel; flexes and extends knee and hip while rotating in a figure 8 fashion
Positive: Pain and/or clicking on joint line

87. Apley Distraction & Compression
Laxity of Ligament/Meniscus
Performed when positive Valgus,Varus, or McMurray’s
Patient: lies prone with legs straight and relaxed
AT: standing at patients involved side. Flexes patients involved knee to 90 degrees. Stabilize upper leg with ATs lower leg. Apply traction to knee (pull up on ankle – towards ceiling) and rotate lower leg.
Positive
pain = capsule or ligament
No pain = meniscus