1. The Knee Lecture 11

3. The Knee Complex
the knee is a large complex joint frequently injured during sport participation
the knee is positioned between the two longest bones in the body - the femur and the tibia creating potential for high torque’s
this factor coupled with poor bony stability makes the knee very susceptible to injury

4. Tibiofemoral Joint
articulation of the distal femur and proximal tibia form a modified hinge joint
movement in 2 planes - Flex /Ext , lnt /Ext rotation
because of the size and shape of the condyles the tibia can rotate on the femur

5. this lateral rotation of the tibia on the femur (only a few degrees) provides a locking of the knee or a "screwing-home mechanism"
stability and support provided by menisci and supportive ligaments

7. Menisci
are fibrocartilage discs that are attached to the tibia by coronary ligaments and joint capsule
they are thicker along the lateral margin and thinner medially
- the medial meniscus is injured more frequently than the lateral meniscus
blood supply only in outer 1/3 of meniscus

9. Medial Meniscus
'C' shaped, strongly attached to the tibial surface therefore less mobile
one reason injured more often
also attached to the joint capsule (medially)

10. Lateral Meniscus
more complete ( almost circle shaped)
loosely attached to tibial surface - less commonly injured

11. Functions of the Menisci
stability - deepens socket and wedge shaped to prevent A-P motion
-increase surface area of femoral condyles
shock absorption
provide nutrition because it promotes synovial fluid flow and distribution - proprioception function through its innervation

12. Meniscal Tears
associated with ligaments disruptions, degenerative changes, repetitive stress secondary to chronic ligamentous laxity, isolated or repetitive rotational stresses

13. Ligaments of the Knee
the stabilizing role of the ligaments that cross the knee is very significant
two major ligaments are the anterior and posterior cruciates ( called cruciate because they cross each other inside the knee joint)
two other ligaments are the medial and lateral collateral ligaments

14. Anterior Cruciate Ligament
separated into to bundles according to their functions, ( not really separate)
spiral around one another, insert as one board ligament spiral arrangement plus the broad attachment allow ACL to provide stability through out the full ROM

15. ACL most common and serious injury to the knee
susceptible to injury with a valgus force, external rotation strong quad contraction of knee hyperextension
ACL is subject to deceleration injuries , internal tibial torque is the most dangerous loading mechanism, particularly when combined with an anterior tibial force

17. Posterior Cruciate Ligament
not as commonly injured as ACL
stronger and shorter than the ACL
prevents posterior tibial translation and knee hyperextension
common mechanism collision or fall on tibial tuberosity

18. Medial Collateral Ligament
provide valgus, external rot support (note ACL is also very imp in this function)
basically a thickening of the medial capsule
superficial layer and a deep layer

19. Lateral Collateral Ligament
cord like structure considered to be extra capsular
less commonly injured b/c of varus mechanism and less debilitating

20. Dynamic Knee Support ITB, hamstrings, quads , gracilis , gastroc
the key to injury rehab and prevention

22. Bursae
Suprapatellar, prepatellar, superficial infrapatellar and deep infrapatellar
i) suprapatellar largest in the body lies between the femur and the quads tendon of the rectus femoris
ii) prepatellar - located between skin and anterior surface of patella
allowing for movement of then skin over the patella

23. iii) superficial infrapatellar - located between the skin and the patellar tendon
-inflammation this are due to excessive kneeling referred to as housemaid's knee
iv) deep infrapatellar - located between the tibial tuberosity and the patellar tendon
reduces friction between tendon and bony tuberosity

26. Patellofemoral Joint
patella articulates with the femur

27. Patella largest sesamiod bone in the body
located within the quads tendon
articulates with the femoral condyles
patella facets -under surface of patella

28. Common Injuries to the Knee

29. 1) Contusions and Bursitis
result from a compressive force - a fall , a kick
generally they are locally tender, with pain, swelling and ecchymosis
Bursitis - may be caused by a direct trauma or possibly infection
swelling usually occurs over a 24 hour period
Rx - PIER - protection - may need draining but this may add complications

30. 2) Ligament Injuries one plane instabilities
i) MCL
pain and swelling usually found along the medial joint line
ii) LCL
pain and swelling are found on the lateral aspect of the knee

31. MCL injuries
straight lateral forces or valgus causes tension on the MCL

32. Signs and symptoms
medial knee pain
Swelling
Medial joint laxity
RX - PIER, hinge knee brace for stability , crutches , most MCL injuries are treated non surgically

35. LCL injuries medial forces or varus force produces tension on the LCL
Much rarer injury than MCL

36. Signs and symptoms
Lateral knee pain
Localized swelling
Lateral joint laxity
RX: PIER, hinge knee brace for stability , crutches , most LCL injuries are treated non surgically

37. ACL injuries
ACL prevents forward translation of the tibia on the femur, also assists with controlling valgus and varus forces , and helps prevent hyperextension
MOI : damage to the ACL usually results from a cutting or turning maneuver, landing off balance or a sudden deceleration

38. s/s
Pain , instability , swelling , may often hear or fell a pop in the knee, decreased ROM and function
pain described as being felt deep in the knee or on either side of the patellar tendon
joint effusion is usually bloody and fairly rapid onset

40. PCL injury PCl prevents the tibia from moving posterior on the femur
MOI: a direct blow to the anterior tibia ( dashboard injury) , or hyperflexion or hyperextension
s/s
Large tense knee effusion
Discomfort attempting to flex the knee beyond 90 degrees
RX: PIER, crutches , referral to surgeon , however this is not often repairs..

41. Multidirectional Instabilities – injuries to multiple structures

43. First Aid Care ( knee ligaments )
Apply ice and compression immediately , brace to protect , crutches
If knee unstable , have athlete seek proper medical advice
Most ACL tears are referred to a orthopedic surgeon, due to the continued instability of the knee
Repairs….

44. 3) Meniscal Injuries
compression, tensile and shearing force often cause damage to the mensci
tears may be - longitudinal , bucket handle , horizontal or parrot-beak
medial mensicus is more often damaged
more common in men between the age of and women between
joint line pain and general joint effusion, pain with rotations and extreme flexion

45. individual may experience clicking , popping or grinding
the knee may give way or buckle
the individual may have difficulty doing squats and or duck walking
the meniscal tear may lodge in the joint causing locking
surgery is usually necessary to unlock this condition mensici become stiffer and less resilient with age
RX – PIER – rest and time possibly surgery

48. First Aid Care Apply ice and compression immediately ,, crutches
If knee blocked or locked , have athlete seek proper medical advice ASAP
Repairs….

49. 4) Patellofemoral Stress Syndrome
usually caused by weakness in the VMO or lateral retinaculum is too tight
this condition is more commonly found in women due to a higher Q angle
Q angle is the angle between the line of the quads ( RF) and the patellar tendon
a Q-angle of less than 13 and more than 18 may predispose the athlete to PFS

50. pain may be dull and aching generally in the centre of the knee or on lateral edge of patella
point tenderness usually over lateral edge of patella, often associated with anterior knee pain
crepitus or grinding often present - especially upon compression of the patella
Rx - PIER - NSIADS -taping- VMO strengthening , education

52. 5) Subluxation or Dislocation of Patella
commonly occurs during deceleration or cutting maneuver
patella moves laterally and may tear medial retinaculum
leading to an audible pop and a collapse of the knee

53. the patella may remain displaced or reduce itself
may need to be reduced by doctor
pain and swelling ,
Rx- PIER, immobilization, exercise and education

54. First Aid Care
Apply ice and compression immediately , splint leg, crutches
Arrange transportation to nearest medical facility

55. 6) Patella Tendinitis aka jumpers knee
patellar tendon becomes inflamed and tender from repeated jumping (eccentric knee extension activities)

56. pain located on inferior pole of patella
pain increases on stairs, after prolonged sitting and during resisted knee extension
as condition worsens time and duration of pain may change or worsen
Rx- PIER, NSAIDS, modalities, exercise and stretching..

57. 7) Osgood-Schlatter Disease
traction type injury to the tibial tuberosity where the patellar tendon inserts
more common in boys aged 10-15
pain and swelling are present with activity usually diminish with rest
in cases with long duration the tibial tuberosity may become enlarged

58. condition usually rectifies itself (within 12 to 24 months) with age and closure of the growth plate
Rx – symptomatic and self limiting

60. 8) Unhappy triad
Medial meniscus
Anterior cruciate ligament and
Medial collateral ligament

61. Possible Factors Influencing Increased rate of ACL injuries in Women
Intrinsic Factors
Ligament size
Ligament laxity
Intercondylar notch dimensions
Limb alignment ( wider pelvis, genu valgum , external tibial torsion)
Estrogen levels

62. Stylistic differences in sport play
Extrinisic Factors
Level of skill
Level of experience
Shoe friction
Ankle braces
Stylistic differences in sport play
Plant and cut, straight leg landing, one step stop landing , pivoting with sudden deceleration
Muscle strength imbalances (eccentric hamstrings strength relative to eccentric quad strength )