1. KNEE TRAUMA Turhan Özler M.D Assistant Professor
Yeditepe University Faculty of Medicine
Department of Orthopaedics & Traumatology

2. Knee Anatomy Strong ligament support Patella: mechanical advantage
collateral lig: resist valgus and varus loading
ACL: two bundles, restrict anteriot motion of tibia, valgus, varus, rotation
PCL: two bundles, restrict posterior motion of the tibia, limits hyper flexion
Patella: mechanical advantage
PFJ huge loads when knee is flexed

3. Knee Anatomy

4. MRI RIGHT KNEE CORONAL
Scan level

5. - MEDIAL LATERAL MENISCI PCL
Saggittal images show menisci, cruciate ligaments and patella ligaments
ACL
MENISCI PATELLA TENDON
LATERAL

6. Knee Injuries
ACL sprain: more common than PCL
Mechanism:
valgus loading and ext tibial rotation (cutting movements)
hyperextension and internal tibial rotation (landing from jumps/rotate)
MRI triad: ACL rupture, osseos lession of terminal sulcus, and bone or soft tissue.

7. SAGITAL MR KNEE (MID JOINT)
QUADRICEPS TENDON
POSTERIOR CRUCIATE LIGAMENT
Scan level
PATELLA
Quadriceps tendon, patella, patellar tendon , anterior cruciate ligament , posterior
Cruciate ligament
ANTERIOR CRUCIATE LIGAMENT
PATELLAR TENDON

8. Knee Injuries
Meniscal tear
Ligament tear

9. Meniscus Anatomy Function Medial Lateral Deepen articular surface
Semicircular(C-shape)
Attached to MCL
Lateral
Circular(O-shape)
No attachment to LCL
Function
Deepen articular surface
Distribute forces

10. Meniscal tear Etiology Frequency Twisting on a planted, flexed knee
Possibly most common knee injury in U.S.
61 cases per 100,000
male-to-female ratio approximately 2.5:1

11. Imaging meniscal tears
MRI
Abnormal signal intensity within meniscus that extends to an articular surface
Abnormal morphology

12. Bow-tie rule
normal meniscal body should be seen as at least two consecutive "bow-ties" on consecutive sagittal images
Normal menisci

13. Common meniscal tears
Oblique tear
Radial tear
“Buckethandle” tear

14. Oblique (parrot beak) tears
Normal Meniscus
Oblique tear

15. Radial tears
Coronal image obtained at the level of line B reveals fluid within the large tear

16. “Inner rim of meniscus pulls away from meniscal body”
Normal Meniscus
Buckethandle tears
“Inner rim of meniscus pulls away from meniscal body”
Buckethandle tear

17. Ligaments of the knee Anterior Cruciate Ligament
Prevents anterior translation of tibia
Posterior Cruciate Ligament
Prevents posterior translation of tibia
Only 90% size of ACL but is strongest knee ligament
Medial Collateral Ligament
Prevents valgus stress
Lateral Collateral Ligament
Prevents varus stress
Posterior Cruciate
Ligament
Anterior Cruciate Ligament
Fibular Collateral
Ligament
Medial Collateral
Ligament

18. Anterior Cruciate Ligament (ACL) Injury
Direct force to the anterior knee, sudden stops or direction change with a planted foot while running or a skier who "catches a tip".
Prevalence higher in females
34% associated w/ audible “pop”

19. Imaging of ACL Tears Primary signs Secondary signs
Plain radiographs usually negative
MRI
proton density with fat suppression studies in sagittal, coronal and axial planes are commonly used for evaluation
normal ACL appears as a low signal intensity band with straight, sharply defined margins
acutely injured ACL will have high T2 signal intensity
increased T1 & T2 signal from associated hemorrhage & edema
sensitivity of 90-98% & specificity of 100
Secondary signs
anterior drawer sign
buckled PCL
uncovering of the posterior horn of the lateral meniscus
bone contusions in a characteristic location
specific but not sensitive

20. Examples
Bone contusions associated with an acute ACL tear. Sagittal fat-suppressed T2-weighted MR image shows ill-defined areas of bone marrow edema involving the lateral femoral condyle (large arrow) and posterolateral aspect of the tibial plateau (small arrow). These are the characteristic locations of bone contusions associated with an acute ACL injury.
ACL tear. Sagittal fat-suppressed T2-weighted MR image shows discontinuity of the midportion of the anterior cruciate ligament (arrow), which is filled with high signal intensity fluid and hemorrhage

21. Posterior Cruciate Ligament (PCL)
Less common than ACL injuries
occurs when a force is applied to the anterior aspect of the proximal tibia when the knee is flexed or when knee is hyperextended
Often associated w/ other injuries
Often minimal to no pain

22. Imaging of PCL Tears Plain radiographs usually negative MRI
proton density with fat suppression studies in sagittal, coronal and axial planes are commonly used for evaluation
performed in extension so PCL will have sharp bend (genu)
Acute tears most commonly manifest with diffuse widening with increased T1 and T2 signal intensity

23. Examples
Fat-suppressed T2-weighted MR image shows a discontinuity and gap involving the midportion of the PCL near the Genu (arrow), which is filled with high signal intensity fluid.

24. Medial Collateral Ligament (MCL) Injury
Most commonly injured knee ligament
Commonly associated w/ other injuries of knee (medial meniscus, ACL)
Contact injuries
direct valgus load to the knee
usual mechanism in a complete tear
Noncontact injuries
deceleration, cutting, and pivoting motions
tend to cause partial tears
Overuse injuries
have been described in swimmers
whip-kick technique of the breaststroke
repetitive valgus loads across the knee

25. Imaging of MCL Tears Plain radiography MRI
should be performed to rule out fractures of the tibial plateau, patella, or distal femur
MRI
coronal images are more accurate than axial images for grading injuries
most sensitive signs are fascial edema and loss of demarcation from adjacent fat

26. Examples
MCL tear. Coronal T2-weighted MR image shows high-signal intensity along the medial aspect of the knee. The medial collateral ligament shows an undulating course with avulsion off of the femoral attachment (arrow).

27. Lateral Collateral Ligament (LCL) Injury
Much less common than MCL injury
Caused by pure varus force
Usually involved in more severe knee injuries
Rare enough I couldn’t find a picture

28. Imaging of LCL Tears Plain radiographs MRI
should be obtained to rule out more common injuries
MRI
procedure of choice for meniscal and ligament evaluation

29. Examples
Coronal T2-weighted MR image shows complex signal along the lateral joint margin. The LCL is torn and retracted proximally (arrow).

30. Knee Injuries ACL & Skiers ACL and females ? backward fall
Anterior drawer mechanism
Phantom boot
back of skis levers flexed knee into internal rotation
ACL and females ?

31. Knee Injuries PCL lower incidence of injuries Mechanism
half of cause due to direct trauma car accidents
Sports
Mechanism
unrestrained occupant thrown against dashboard
fall on flexed knee with plantar flexed knee
force knee flexion
force knee hyperextension
quick rotation

32. Knee injuries Unhappy triad: valgus-external rotation ACL MCL
Medial meniscus damage ?

33. Knee Injuries Meniscus: Full extension 90o flexion
weight bearing
shock absorption
stabilization
rotational facilitation
Full extension
45-50% of the load
90o flexion
85% load
Laterally: 70% of the load 30% AC

34. Knee Injuries Screw home mechanism: medial rotation at full extension
Mechanisn
flexion or extension and rotation
tensile loading of medial meniscus
bucket-handle tear
High incidence sports
soccer, shot put discuss, skiing

35. Knee injuries MCL and LCL sprains Forced varus or valgus loading
Overuse
breaststroke kick

36. Knee injuries KEM: knee extensor mechanism quads PFJ and tendon
Difference forces in the quad tendon and patellar ligament
Depend on Knee angle
Contact force
Patellar tracking
Q angle
Congruence

37. Knee Injuries Jumper’s Knee Chondromalacia Tendon Rupture
Patellar tendon pain
Chondromalacia
degeneration of the retropatellar AC
Tendon Rupture
>40 years
previous microtrauma

38. QUADRACEPS TENDON INJURY
NORMAL
Patella tendon injury

39. ANTERIOR CRUCIATE LIGAMENT INJURY
A test to see if this is still intact is the anterior draw sign where you pull the tibia anterior to the femur. If the ACL is ruptured there will be nothing to prevent the tibia from coming really far forward and you will not feel an end feel.
Normal

40. POST OPERATIVE LIGAMENT REPAIR
They take a piece of you… and drill it in with these screws

41. POSTERIOR CRUCIATE LIGAMENT INJURY
Posterior draw sign. Push the tibia posterior to the relative to the femur and if it is ruptured there will be no end feel and the tibia will go really far posterior
normal

42. MENISCUS
NORMAL
TORN