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©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 1 of 16 Knee Imaging
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 1 of 92
3 Bones Femur
Patella
Tibia (Fibula)
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 2 of 92
Patella: [L] “shallow pan” Largest sesamoid bone Sesamoid: “Bone embedded
within a tendon” Many sesamoids throughout
body, particularly in the foot
2 Great Toe sesamoids (100%)
os peroneum (~30%)
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 3 of 92
Patella: [L] “shallow pan” Largest sesamoid bone Sesamoid: “Bone embedded
within a tendon” Quadriceps tendon From 4 quadriceps muscles Vastus Lateralis, Medialis, Intermedius Rectus Femoris
To tibial tubercle (tuberosity) “Extensor Mechanism”
Patellofemoral Compartment
Patella: [L] “shallow pan” Bones
Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 4 of 92
Articular Surfaces Trochlear groove trochlea: [L] “pulley” Patellofemoral compartment
Femoral Condyles condyle: [Gk] “knuckle”
round knob at end of a bone Medial/Lateral compartments
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 5 of 92
Femoral Condyles Anterior View Lateral View Posterior View
Intercondylar Notch
Lateral Compart Medial
Compart
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 6 of 92
Articular Surfaces As opposed to the round articular surfaces of the femoral condyles, the tibial articular surfaces are flat. Tibial plateau: [Fr] “plate”
Anterior View Lateral View Posterior View
Tibial Eminence
Lateral Compart Medial
Compart
Eminence separate the lateral & medial compartments
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 2 of 16 Knee Imaging
Bones Patella Femur Tibia
Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 7 of 92
Tibial Eminence
A,K 54yoF
Tibial Eminence
Jan: “Hurt knee skiing” Nov: “Knocked down by dog”
Fracture tibial eminence Transverse fracture ↔
= Avulsion fracture Avulsion of ACL
(Anterior Cruciate Ligament)
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 8 of 92
Knee Imaging Radiographs (78%) Primary modality for knee pain Arthritis (joint narrowing, osteophytes) Fractures, loose bodies
MR (21%) Internal derangement Ligament/meniscal tears, cartilage defects
Occult fractures
CT (1%) Surgical planning (of fxs seen on radiographs)
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 9 of 92
AP View Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 10 of 92
AP View Shows width of lateral, medial compartments Assess for arthritis Doesn’t show patello-
femoral compartment
Articular surfaces Weight-bearing portions
femoral condyles Tibial plateau Assess for displaced
fractures
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 11 of 92
Lateral View Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 12 of 92
Lateral View Shows lateral view of femoral condyles & tibial plateau Doesn’t show med/lat compartments
Shows lateral view of patella Assess for patella fracture Doesn’t show patellofemoral compart
Can show sizable joint effusions… physical exam is more sensitive!
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 3 of 16 Knee Imaging
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 13 of 92
Sunrise View (Laurin View) Shows patellofemoral compart! Important view to assess arthritis
Shows alignment between patella & trochlear groove.
Patella
www.ejbjs.org/cgi/reprint/60/1/55
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 14 of 92
Notch View (Rosenberg)
www.ejbjs.org/cgi/reprint/70/10/1479
Bones Radiographs
AP View Lateral View Sunrise View Notch View
Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 15 of 92
Notch View (Rosenberg) Shows width of posterior lateral, medial compartments Assess for arthritis Doesn’t show patellofemoral
compartment
Articular surfaces Posterior portions femoral condyles Tibial plateau Assess for displaced fractures
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 16 of 92
Fluid in Joint: Effusion Synovial fluid From inflamed synovium Arthritis
Blood: “Hemarthrosis” From torn vascularized structure Anterior Cruciate Ligament tear
Fat + Blood: “Lipohemarthrosis” Fat comes from fatty yellow bone marrow Indicates presence of intra-articular fracture
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 17 of 92
Suprapatellar Pouch The knee can hold a lot of fluid… not between articular surfaces. Joint effusions collect in the suprapatellar pouch. Synovial lined space Normal extension of the
joint capsule Can easily hold > 40ml
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 18 of 92
H,B 15yoM
Large effusion
Effusion on Lateral View No effusion
(radiographically)
Radiographs can show sizable joint effusions… but physical exam is more sensitive!
B,C 13yoF
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 4 of 16 Knee Imaging
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 19 of 92
Effusion on Lateral View
Effusion
MR: T2fs
Sagittal
Radiographs are relatively insensitive
for fluid. M,C 54yoF
T2 (fat suppressed) extremely sensitive
for fluid.
?
Effusion on MR Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 20 of 92
Effusion on MR
M,C 54yoF
Proton Density doesn’t show fluid very well.
MR: PD
Sagittal
Effusion
MR: T2fs
Sagittal
T2 (fat suppressed) extremely sensitive
for fluid.
MR: T2fs Axial
Suprapatellar pouch wraps around femur
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 21 of 92
Effusion on MR
M,C 54yoF
MR: T2fs Sagittal thru Medial Compart
MR: T2fs Sagittal thru Lateral Compart
Effusion Effusion
Suprapatellar pouch
Baker cyst
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 22 of 92
Baker Cyst (Popliteal Cyst) Suprapatellar pouch Synovial lined space Normal place fluid collects
Baker cyst Synovial lined space Abnormal place fluid collects Posterior extension joint capsule Medial, between: Medial gastrocnemius muscle One of the calf muscles
Semi-Membranosis tendon One of the hamstring muscles
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 23 of 92
Baker Cyst (Popliteal Cyst)
Baker cyst
MR: T2fs Sagittal Medial Compart
PD Sagittal Medial
Medial Gastroc Muscle
Semi- Mem Musc
Origin: Above Femoral Condyle
Insert: Below Tibial Plateau
M,C 54yoF
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 24 of 92
Baker Cyst (Popliteal Cyst)
P,T 51yoF
PD Coronal Far Posterior T2fs Coronal Far Posterior
Lateral Gastroc Muscle
Medial Gastroc Muscle
Lateral Gastroc Muscle
Medial Gastroc Muscle
Lateral Gastroc Muscle
Medial Gastroc Muscle
Semi- Mem Musc
Semi- Mem Musc
Baker cyst
Semi- Mem Musc
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 5 of 16 Knee Imaging
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 25 of 92
Prepatellar Bursitis Prepatellar Bursa Synovial lined space Does not communicate with
knee joint capsule Normally contains little/no fluid
Irritation of bursa marked increase bursal fluid Prepatellar bursitis reported in
people who kneel frequently Housemaid’s knee Preacher’s knee
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 26 of 92
Prepatellar Bursitis Often diagnosed by exam Often diagnosed by exam
http://en.wikipedia.org/wiki/Prepatellar_bursitis
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 27 of 92
Prepatellar Bursitis MR: T2fs Sagittal
Prepatellar swelling
S,R 61yoM H,K 61yoM
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 28 of 92
Loose Bodies Fragments of bone/cartilage in capsule Loose osteochondral fragment
May be inconsequential if outside joint If remain in suprapatellar pouch, or in Baker cyst
But if between articular surfaces… May cause locking, Destruction articular cartilage
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 29 of 92
Loose Bodies
H,N 62yoF MR: T2fs Sagittal MR: PD Sagittal
Loose Bodies in Suprapatellar Pouch
Loose Bodies in Baker Cyst
? Loose Bodies in Suprapatellar Pouch
Baker Cyst
Loose Bodies where?
Osteophytes
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 30 of 92
Loose Bodies
D,N 23yoM
MR: PD Coronal
…one week later
Lateral View AP View
Loose Body in Anterior Joint
Loose Body in Medial Compart Loose Body in
Lateral Compart
Loose Body in Suprapatellar
Pouch
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 6 of 16 Knee Imaging
Bones Radiographs Fluid
Suprapatellar Baker cyst Prepatellar Loose bodies
Fabella
Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 31 of 92
Fabella: [L] little bean Sesamoid lateral gastrocnemius Present 10-30% people Bilateral 80%
http://www.ajronline.org/cgi/reprint/183/2/352
Not a loose body
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 32 of 92
Fractures Patella Uncommon Direct trauma, fall to patella Distraction – fragments pulled apart
Femur Condyle fracture – rare Supra/Intra-condyle fx – more common Osteochondral defect – fairly common
Tibia Plateau MVA – Very Common
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 33 of 92
Bipartite Patella
T,T 15yoF
Not a fracture
AP View Notch View
Sunrise View
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 34 of 92
Bipartite Patella Normal variant 2% of population 9x more common boys Bilateral 43% Asymptomatic 98% Usually superolateral
www.radswiki.net/main/index.php?title=Bipartite_patella JP Lawson. Radiology 1985 157: 625-631. T,T 15yoF
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 35 of 92
Patella Fractures (Uncommon)
B,I 22yoM
Direct Trauma (Fall onto knee) Comminuted, stellate pattern Typically not distracted
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 36 of 92
Patella Fractures (Uncommon) Indirect distracting injury Unexpectedly rapid knee flexion
against contracted quadriceps Distraction upper/lower poles
M,M 64yoM
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 7 of 16 Knee Imaging
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 37 of 92
Condyle fractures: rare Supra-condylar Inter-condylar
Anterior View Lateral View
Femur Fracture Posterior View
more common
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 38 of 92
Uncommon Fx Results from shearing
of condyle as femur is dislocated across tibia
Lateral View
Femoral Condyle Fracture
A,J 58yoM
CT
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 39 of 92
Femoral Supra/Inter Condylar Fractures More common From axial loading Fracturing between condyles Fracturing above condyles
Increasingly common Older females (low energy) Younger males (high energy)
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 40 of 92
Femoral Supra/Inter Condylar Fractures From axial loading
L,L 49yoF
with traction Femoral shaft impacted into/
between condyles
CT
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 41 of 92
Osteochondral Defect (OCD) Fairly common
M,A 24yoM
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 42 of 92
Osteochondral Defect (OCD) Fairly common Fx of bone “osteo” & cartilage “chondral” Adults: traumatic Children: idiopathic
“osteochondritis dissecans”
Femoral condyles Medial 4x > Lateral
M,A 24yoM
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 8 of 16 Knee Imaging
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 43 of 92
Imaging Osteochondral Defects Start with radiographs… CT shows corticated margin MR shows “stability”
These should be ordered by
orthopedic surgeon MR: Coronal T1 CT: Coronal Reformat
M,A 24yoM
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 44 of 92
Imaging Osteochondral Defects: MR Coronal T1 Post-op Coronal T2fs
Sagittal T2fs Arthroscopy Arthroscopy
M,A 24yoM
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 45 of 92
Tibial Plateau Fractures Very Common 80% MVA (the rest from falls, sports)* 60% involve lateral plateau** CT used for surgical planning Schatzker classification system*
* http://emedicine.medscape.com/article/1249872-overview ** http://www.wheelessonline.com/ortho/tibial_plateau_fractures
I II III IV V VI
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 46 of 92
Tibial Plateau Fracture (SII) 46yo♂ physician injured knee skiing Walked around with knee pain 4 days When not improved went for imaging...
MR: Coronal T2fs
G,L 46yoM CT: Coronal Reformat
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 47 of 92
Tibial Plateau Fracture (SII)
G,L 46yoM CT: 3D Reformat CT: Coronal Reformat
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 48 of 92
Tibial Plateau Fracture (SII)
G,L 46yoM
Intra-operative
Post-operative
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 9 of 16 Knee Imaging
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 49 of 92
Non-displaced (Occult) Fractures The way we diagnose fractures on radiographs
is to see displaced fragments. Non-displaced Fx can be radiographically occult.
So how do we detect occult knee fractures? CT often doesn’t help. Fxs non-displaced by radiographs are non-displaced on CT
MR doesn’t miss non-displaced Fxs. Can’t send every ER patient with knee pain to MR
There is a trick! Look for lipohemarthrosis on cross-table lateral!
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 50 of 92
Radiographic Views: In Clinic AP & Lateral views shot with patient standing.
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 51 of 92
Radiographic Views: In ER Shot with patient lying on a cart. AP view Vertical X-ray beam
X-r
ay
s
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 52 of 92
Radiographic Views: In ER Shot with patient lying on a cart. Lateral view Vertical X-ray beam Parallel to gravity
X-r
ay
s
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 53 of 92
Shot with patient lying on a cart. Cross-Table Lateral view Horizontal X-ray beam Perpendicular to gravity
UW MSK Policy: All ER knees shot X-Table Lat.
Radiographic Views: In ER Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 54 of 92
Types of Joint Effusions Synovial fluid From inflamed synovium Arthritis
Blood: “Hemarthrosis” From torn vascularized structure Anterior Cruciate Ligament tear
Fat + Blood: “Lipohemarthrosis” Fat comes from fatty yellow bone marrow Indicates presence of intra-articular fracture
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 10 of 16 Knee Imaging
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 55 of 92
Thought Experiment
Lipo- hem-
arthro- sis
Whole Blood
Cells
Plasma
Cells
Plasma
Fat Whole Blood
X-rays X-rays X-rays
perpen- dicular
to gravity
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 56 of 92
Lipohemarthrosis on X-Table Lateral
Fat
Fluid
Fat-Fluid Level = Lipohemarthrosis =
Intra-Articular Fracture
P,A 27yoF
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 57 of 92
Lipohemarthrosis on X-Table Lateral CT: Coronal Reformat
P,A 27yoF
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 58 of 92
Impacted Tibial Plateau Fracture (SIII) CT: Coronal Reformat
CT: Sagittal Reformat
P,A 27yoF
Intra-operative Fluoroscopy
Post Operative
Repaired with just:
2 Screws
Bone Cement
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 59 of 92
P,P 63yoF
Occult Fracture AP View
XTL View
Lipohemarthrosis
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 60 of 92
P,P 63yoF
AP View CT: Coronal Reformat
XT
L V
iew
Occult Fracture
?
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 11 of 16 Knee Imaging
Bones Radiographs Fluid Fractures
Patella Femur
OCD Tibia Occult Fxs
Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 61 of 92
P,P 63yoF
MR Doesn’t Miss Fractures
MR: Coronal T2fs
AP View MR: Coronal T1 CT: Coronal Reformat
? Bone Marrow
Edema
Black Fx Lines
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 62 of 92
Ligaments & Tendons Tendons Connect muscles to bone Quadriceps Tendon
Ligaments Connect bone to bone Patella Ligament Anterior Cruciate Ligament (ACL) Medial Collateral Ligament (MCL)
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 63 of 92
Most commonly rupture >50yo Men 8x > Women
Transversely, patella insertion Exam: Patella freely mobile Inability to actively extend knee Active flexion preserved
Radiographs: May show low patella “patella baja”
www.wheelessonline.com/ortho/rupture_of_the_quadriceps
Quadriceps Tendon Rupture Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 64 of 92
P,S 56yoM
MR: Sagittal T2fs MR: Sagittal PD
Quadriceps Tendon Rupture
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 65 of 92
www.wheelessonline.com/ortho/patellar_tendon_avulsion
Most commonly rupture <40yo More common in African descent
Transversely, patella origin Exam: Inability to actively extend knee
Radiographs: May show high patella “patella alta”
Patella Ligament Avulsion Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 66 of 92
Patella alta: Patella ligament >20% longer Patella length.
Normally
patella length = patella lig. length
(+/- 20%) Courtesy of Kirkland Davis, MD
Patella Ligament Avulsion
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 12 of 16 Knee Imaging
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 67 of 92
Patella Ligament Avulsion
T,D 42yoM
MR: Sagittal T2fs MR: Sagittal PD Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 68 of 92
Normal MCL
MR: Coronal PD
From above condyle to below plateau Frequently injured Lateral clipping injury Valgus stress on knee
MR: Coronal PD
MCL Avulsion off Tibial Insertion
Medial Collateral Ligament (MCL)
P,M 28yoM
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 69 of 92
3 Structures Iliotibial Band Biceps Femoris Tendon Fibular Collateral Ligament Infrequently injured
Lateral Collateral Complex
MR: Coronal PD
ITB
MR: Coronal PD
FCL BFT
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 70 of 92
Cruciate Ligaments Cruciate: [L] “cross” Anterior Cruciate Ligament crosses anterior to the Posterior Cruciate Ligament ACL: Lat Fem Cond
Med Tib Spine PCL: Med Fem Cond
Lat Tib Spine
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 71 of 92
Cruciates Cross in Both Planes MR: Sagittal PD CT: Sagittal Reformat
ACL
PCL
ACL
PCL
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 72 of 92
Cruciate Ligament Tears PCL infrequently tears Surgical reconstruction of the PCL
is controversial
ACL frequently tears Requires surgical reconstruction Sports related twisting injury Torn ACL allows anterior displacement of
the tibia relative to the femur. Anterior Draw Sign
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 13 of 16 Knee Imaging
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 73 of 92
Anterior Draw Sign = ACL Tear
S,E 58yoM
Not usually seen on radiographs but… More common on MR
N,G 16yoM
MR: Sagittal PD
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 74 of 92
Back of tibial plateau impacts upon front of femoral condyle Bone marrow contusions/edema
Kissing Contusions = ACL Tear
B,W19yoM
MR: Sagittal T2fs MR: Sagittal PD
BME
BME
Less sensitive for fluid Very sensitive for fluid
Black Fx Lines
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 75 of 92
Back of tibial plateau impacts upon front of femoral condyle Bone marrow contusions/edema Impaction fractures Anterior lateral femoral condyle Posterior lateral corner tibial plateau
Impaction Fractures from ACL Tear
MR: Sagittal T2fs MR: Sagittal PD
W,S 45yoM
BME
BME
Bones Radiographs Fluid Fractures Ligaments
Quadriceps Collaterals Cruciates
ACL Tears
Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 76 of 92
ACL Tears on MRI Direct sign: Non-visualization
of intact fibers Indirect signs: Anterior draw Kissing
contusions
Sagittal T2fs Sagittal PD J,D 17yoF
B,E 22yoF
Sagittal T2fs Sagittal PD
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 77 of 92
Menisci Looking at the menisci is the primary indication for ordering MRI of the knee To assess for fractures, arthritis Order radiographs
Surgical planning fracture repair Order CT
To assess for ACL tear At least start with physical exam…
To assess for meniscal tear Radiographs, PE not helpful Order MRI!
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 78 of 92
Menisci: Function To improve contact between: Curved femoral condyles Flat tibial plateau Composed of fibrocartilage Triangular in cross-section Function like “O”-rings… “C”-shaped
MM LM
Function
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 14 of 16 Knee Imaging
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 79 of 92
Menisci: C-shaped
A
P
A
P
MM LM
A
P
MM LM
Sagittal
PH AH
Sagittal
PH AH
Sagittal
MB
Mid Body
Sagittal PD
Sagittal PD
Sagittal PD
Coronal PD MB MM
MB LM
S,M 32yoM
AH PH
AH PH
MB
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 80 of 92
Meniscal Tears Meniscal tears are seen on MR as increased signal that extends to an articular surface on at least 2 slices 1 slice only touches called “possible tear” 50% of these are torn at arthroscopy Articular surfaces:
Superior
Inferior
Not an articular surface
Free Edge
Free Edge
Arthroscopic View
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 81 of 92
Horizontal Tear “Cleavage tear” Cleaves the
meniscus into upper/lower
Sagittal PD
Coronal PD
PH MM
PH MM
A,R 50yoM
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 82 of 92
Longitudinal Tear “Vertical tear” Separates
meniscus into inner/outer
Sagittal
PH AH
Sagittal PD
Coronal PD Axial T2fs
PH MM AH MM
MB MM
P,B 18yoF
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 83 of 92
Radial Tear Radiates from free edge outward Separates
meniscus into anterior/posterior
MM LM
Coronal
MB LM MB MM
MB MM
MB MM
Coronal T2fs
Coronal PD
E,S 57yoM
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 84 of 92
Flipped Meniscal Fragment Meniscus portion displaced within knee joint Can cause locking Decreased motion
PH
AH AH
PH
AH LM
PH LM
Sagittal PD
N,D 46yoM
Sagittal
PH
AH
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 15 of 16 Knee Imaging
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 85 of 92
Bucket Handle Tear Longitudinal tear where inner portion flips into the intercondylar notch, under PCL
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 86 of 92
Bucket Handle Tear Longitudinal tear where inner portion flips into the intercondylar notch, under PCL
Coronal
MB LM Bucketed MB MM
MB MM
Coronal T2fs
Coronal PD
A,D 18yoM
MB MM
MB LM
Bucketed MB MM
PCL
Bones Radiographs Fluid Fractures Ligaments Menisci
Normal Anatomy Horizontal Tear Longitudinal Tear Radial Tear Flipped Fragment
Bucket handle
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 87 of 92
Bucket Handle Tear Longitudinal tear where inner portion flips into the intercondylar notch, under PCL
Sagittal PD
PCL
Bucketed MB MM
H,D 15yoM
Double PCL sign
Coronal T2fs
Coronal PD
MB MM
MB LM
PCL
Bucketed MB MM
Bones Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 88 of 92
Knee: What to Order When (WOW) Always start with radiographs!
Diagnose arthritis, assess progression Joint space narrowing, osteophytes
Diagnose fractures, assess healing Fracture displacement, articular involvement
Look for loose bodies See if bodies move over time
Screen for unexpected findings Tumors Metal foreign bodies
Bones Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 89 of 92
Knee: What to Order When (WOW) Radiographs: Need at least 3 views 1) AP Med & Lat: Condyles, Plateau, Compartments
2) Lateral Perpendicular to AP view Shows Patella ER: X-Table Lateral may show lipohemarthrosis
3) Sunrise Best view for patellofemoral compartment
--------------------------------------------------------- 4) Notch (part of a 4-view series) Shows posterior condyles
Bones Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 90 of 92
Knee: What to Order When (WOW) MRI: Frequently ordered for knee pain Internal derangement Meniscal tears Ligament tears (ACL, MCL) Cartilage defects
Occult/non-displaced fractures MRI does not miss fractures
BEST IF ORDERED BY KNEE SPECIALIST! They may prefer certain sequences They may prefer certain MR scanners
©Ken L Schreibman, PhD/MD 4/8/11 www.schreibman.info
page 16 of 16 Knee Imaging
Bones Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 91 of 92
Knee: What to Order When (WOW) CT: Infrequently ordered for knee pain
Primary use is in the ER to assess the alignment of fracture fragments (shown on radiographs) to aid in surgical planning Should be ordered by the surgical team
Occasionally, for patients who are not MR compatible, we will do an Arthrogram-CT to assess for internal derangement Should be ordered by the knee specialist
Bones Radiographs Fluid Fractures Ligaments Menisci
© 2011 Ken L Schreibman, PhD/MD www.schreibman.info
Knee Imaging Wisconsin Physical Therapy Association 4/8/11
Slide 92 of 92
Questions?
P,D 59yoM
MR: Coronal T2
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