Post on 05-Jan-2016
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Standard Knee SeriesStandard Knee Series
• AP Knee
• Lateral Knee
• Tunnel Knee
AP Knee
• pt is positioned with 15o of internal rotation of the foot
• femorotibial joint spaces should measure between 5-11 mm
Lateral KneeLateral Knee
• approximately 30-35 degrees of flexion of the knee
Blumensaat’s lineBlumensaat’s line
• Dense white line representing the surface of the intercondylar notch that is tangential to the x-ray beam.
Ludloff’s Ludloff’s PatchPatch
• A lucency in the distal distal femoral femoral epiphysisepiphysis
• best seen around the age of 16 years
3 year male
• The ossification center for the patella is first apparent.
• normal patellar ossification does not begin until 1.5-5 years years of ageof age
• The patellar ossification center is more prominent, and a normal pronounced indentation is evident at the anterior portion of the tibia at the eventual site of the tibial tubercle.
5 year male
Patellar PositionPatellar Position
• Patella AltaPatella Alta - patellar ligament greater than 20% longer than the patella
• Patella BajaPatella Baja - patella positioned too low
the greatest length of the patella and the length of the the greatest length of the patella and the length of the patellar tendon (ligament) should be equal (20% patellar tendon (ligament) should be equal (20% variation is acceptable)variation is acceptable)
Tunnel KneeTunnel Knee
• approximately 45o of knee flexion and a 45o caudad tube tilt
Accessory ProjectionsAccessory Projections
Tangential Tangential Patella Patella
• aka Sunrise Patellaaka Sunrise Patella• lateral vs medial
patellofemoral joint space
Lateral Medial
Bilateral AP Weightbearing Bilateral AP Weightbearing KneesKnees
Oblique Oblique KneeKnee
Normal Variants of the KneeNormal Variants of the Knee
Patella agenesis
• Rare.• Usually associated
with hereditary osteo-onychodysostosis.
Nail Patella Syndrome AKA Nail Patella Syndrome AKA Fong’s Syndrome, HOOD Fong’s Syndrome, HOOD
syndromesyndrome• hypoplastic or absent
patella• nail abnormalities• may see kidney
dysfunction and webbing of the elbow
• iliac hornsiliac horns• elbow abnormalitieselbow abnormalities
Harris LinesHarris Lines
• aka Growth Arrest Growth Arrest LinesLines
• represents areas of growth arrest resolution
Bipartite Bipartite PatellaPatella
• bilateral 80% of the time
Tripartite Tripartite PatellaPatella
Os Os CyamellaCyamella
• accessory ossicle in the popliteus popliteus tendontendon
Os FabellaOs Fabella
• sesamoid bone located within the tendon of the lateral head of lateral head of the the gastrocnemius gastrocnemius musclemuscle
• bilateral in 2/3 to 3/4 of individuals
Dorsal defect of the patella
• Variant in ossification.• Circular radiolucent
defect in superolateral pole of patella.
• May simulate neoplasm.• May be related to
bipartite patella.
• Self limiting.• Incidental finding in
children.
Osgood-Osgood-Schlatter’s Schlatter’s
DiseaseDisease
• m/c in males • 11 - 15 years of age
• fragmentation of the tibial tuberosity
Sinding-Larsen-Sinding-Larsen-Johannsen Johannsen SyndromeSyndrome
• inferior pole of the patella
Pellegrini-Pellegrini-SteidaSteida
• calcification of the medial collateral medial collateral ligamentligament
• usually follows previous trauma
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Name the Name the VariantVariant
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