Patellar sleeve fracture: demonstration with MR imaging.
OBJECTIVE
To demonstrate the magnetic resonance (MR) imaging characteristics of patellar sleeve fracture, a cartilaginous avulsion from the lower pole of the patella occurring during forceful contraction of the quadriceps muscle against a partially flexed knee.


METHODS
The authors evaluated radiographs and MR images from three children with suspected sleeve fractures.


RESULTS
Radiographs showed small bone fragments avulsed from the lower patella in two children and no bone abnormality in one. MR imaging demonstrated separation of most of the cartilaginous lower patella in all children, definite intraarticular extension in one, and possible intraarticular extension in another.


CONCLUSIONS
MR imaging can help determine the need for surgery by depicting the extent of cartilaginous injury and displacement of fracture fragments.
Department of Radiology, Children's Hospital, Boston, MA 02115.
D G
DG
Bates
M T
MT
Hresko
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D
Jaramillo
D002356:Cartilage / Q000293:injuries*; D002648:Child; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis*; D050724:Fractures, Cartilage; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010329:Patella / Q000293:injuries*; D012189:Retrospective Studies