Radiologic Eval of Knee Flashcards
list radiologic views that are including during a routine exam of the knee
- AP
- Lateral
- PA axial “tunnel” view of the intercondylar fossa
- Tangential view of patella
- Other
- WBing posterioanterior axial view of the intercondylar fossa
- oblique view
describe the tangential view of the patellofemoral joint
- x-ray path superioinferior (merchant view) or inferiosuperior
- Spatial relationships
- patellar subluxations
- sulcus angle
- congruence angle
what is the norm for the sulcus angle?
138 +/- 6 degree
what is the norm of the congruence angle?
-6 degree normal
+16 deg associated with lateral subluxation
general guidelines for imaging at the knee
- X-rays typically first study for suspected bony and soft tissue abnormalities
- diagnosis
- directs further imaging
- CT commonly used for defining complex fractures
- MRI commonly for defining soft tissue injuries
- USI possibly for superficial soft tissue abnormalities
general indications for CT of the knee
- severe trauma
- fracture alignment/displacement
- loose bodies within joint
- tibial plateau depression fractures
- health conditions typically viewed with MRI when MRI is contraindicated
what can be seen with an axial CT of the knee?
- Depression/split fractures of tibial plateau
- Segond fracture
- Tibial tuberosity hypertrophy or fragmentation (Osgood-Schlatter’s)
what can be seen with a sagittal CT of the knee?
- position of the patella
- fragmentation/ossification of inferior patella/patellar tendon
what can be seen with a coronal CT of the knee?
- intercondylar/condylar spilt fractures involving femoral condyles
- osteochondral lesions
- fractures of intercondylar eminence
- ACL avulsion
- Segond fractures with lateral capsule sign
list general indications for MRI of the knee
- soft tissue injuries
- staging disease
- specific clinical scenarios
list soft tissue indications for MRI at the knee
- Meniscal lesions
- Ligament abnormalities
- Extensor mechanism abnormalities
- Osteochondral lesions
- Articular cartilage abnormalities
- Loose bodies
- Synovial disorders
- Marrow abnormalities
- Muscle and tendon disorders
- IT band syndromes
- Neoplasms
- Infections
- Congenital/developmental conditions
- Vascular conditions
- Neurogenic conditions
list staging disease indications for MRI of the knee
- inflammatory arthropathies
- bone/soft tissue tumor
- fractures/dislocations
list specific clinical scenarios that call for MRI of the knee
- prolonged, unexplained knee pain
- acute trauma
- mechanical symptoms
- instability/dislocation
- malalignment
- following complications with knee arthropathy
- limited/painful ROM
- swelling/enlargement/mass
- planned arthroscopy
- residual/new symptoms following surgery
what can be seen with an axial slice of a knee MRI?
- articular cartilage
- patellofemoral ligament
- patellar retinaculum
- ACL/PCL
- Joint effusion
- Popliteal bursa
- popliteus
- pes anserine, inserting muscle/tendon
- muscle bulk
what can be observed with a sagittal slice of a knee MRI?
- articular cartilage
- bone marrow
- menisci
- ACL/PCL
- extensor mechanism
- Hoffa’s fat pad