The deep infrapatellar bursa: prevalence and morphology on routine magnetic resonance imaging of the knee.
OBJECTIVE
To evaluate the presence, location, and dimensions of the deep infrapatellar bursa on routine magnetic resonance (MR) imaging of the knee.


METHODS
The study group consisted of 213 knees in 204 consecutive individuals who had undergone routine MR imaging examination of the knee within a 365-day period. Magnetic resonance examinations consisted of T1-, proton-density-, and T2-weighted sagittal; spectral presaturation inversion recovery coronal; and T2*-weighted transverse sequences. Exclusion criteria were previous knee arthroscopy or surgery or the presence of a mass lesion infiltrating the infrapatellar fat pad. The presence, location, and dimensions of the deep infrapatellar bursa were studied. The bursa was also analyzed with regard to knee joint synovial effusion (absent, mild, or marked).


RESULTS
The deep infrapatellar bursa was detected in 68% of the knees, most commonly on the lateral paramedian sagittal MR images. There was no statistically significant difference between male and female subjects or between the knee sides with regard to the detection of the deep infrapatellar bursa (P > 0.05). No correlation was found between synovial effusion and the presence of the deep infrapatellar bursa. The mean anteroposterior and craniocaudal dimensions of the deep infrapatellar bursa on sagittal T2-weighted MR images were 2.1-2.7 mm and 7.3-9.1 mm, respectively, on its lateral, central, or medial location within the sagittal MR image stack.


CONCLUSIONS
An awareness of the dimensions and location of the deep infrapatellar bursa is important in distinguishing it from pathologic lesions (eg, bursitis).
Aydingoz
Ustun
U
Department of Radiology, Hacettepe University Medical School, Ankara, Turkey. uaydingo@hacettepe.edu.tr
Oguz
Berna
B
Aydingoz
Onder
O
Comert
Ruhi Baris
RB
Akgun
Isik
I
D000293:Adolescent; D000328:Adult; D000368:Aged; D002061:Bursa, Synovial / Q000473:pathology*; D002062:Bursitis / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000473:pathology*; D012737:Sex Factors; D018709:Statistics, Nonparametric; D013582:Synovial Fluid; D013585:Synovitis / Q000175:diagnosis