Quantification of intact quadriceps tendon, quadriceps tendon insertion, and suprapatellar fat pad: MR arthrography, anatomy, and cryosections in thesagittal plane

OBJECTIVE. The purpose of this study was to quantify quadriceps tendon leng th, thickness, and insertion in relation to the suprapatellar fat pad. SUBJECTS AND METHODS. We used three methods to analyze the anatomy of intac t quadriceps tendons and insertions into the patellar base: MR arthrography (53 knees with intact extensor mechanisms), gross anatomy (16 cadaveric kn ees), and cryosections (four cadaveric knees). With an electronic cursor, t wo observers independently quantified the extensor mechanism on midline sag ittal T1-weighted spin-echo sequences acquired on a low-field-strength (0.2 3 T) scanner. RESULTS. On MR arthrograms, quadriceps tendon length, determined from the s uperior patellar pole to the most superior part of the suprapatellar recess , measured 49 +/- 7 mm in women and 50 +/- 9 mm in men. Thickness of quadri ceps tendon at three sites (suprapatellar recess, center, and superior pate llar pole) measured 7 +/- 1 mm in women and 8 +/- 1 mm in men. Thickness wa s significantly larger in men at all measurement locations. Quadriceps tend on insertion and the suprapatellar fat pad along the patellar base measured 16 +/- 2 and 6 +/- 2 mm, respectively, in women, and 18 +/- 3 and 7 +/- 2 mm, respectively, in men. CONCLUSION. On midline MR images, sagittal thickness of the quadriceps tend on and its insertion was significantly larger in men than in women. The pre valence of the suprapatellar fat pad was 100%.