PMC9091402_01
Coronal proton density fat-saturated MRI images show the quadruple cruciate sign in the intercondylar notch (a) formed by the menisci (arrowheads), PCL (yellow arrow), and ACL (green arrow). (b) The truncated meniscus (encircles) with medial meniscus double anterior horn sign (red arrow).
JOCR-12-79-g001.jpg
PMC9091402_01_JOCR-12-79-g001.jpg
F1
T1-weighted image and gradient echo image. The MRI was diagnostic of a complete chronic ACL tear, medial, and lateral meniscal tears with bucket handle components giving rise to the "triple posterior cruciate ligament (PCL)" sign, double anterior horn sign, and an osteochondral defect in the medial femoral condyle (Fig. 1, 2).
Sagittal proton density fat-saturated MRI images show the double anterior horn sign (red arrow) and absent bow tie sign (red arrowhead) in (a) and the triple PCL sign in (b) formed by the PCL (yellow arrowhead) and flipped menisci (red arrowhead).
JOCR-12-79-g002.jpg
PMC9091402_01_JOCR-12-79-g002.jpg
F2
T1-weighted image and gradient echo image. The MRI was diagnostic of a complete chronic ACL tear, medial, and lateral meniscal tears with bucket handle components giving rise to the "triple posterior cruciate ligament (PCL)" sign, double anterior horn sign, and an osteochondral defect in the medial femoral condyle (Fig. 1, 2).
Proposed novel MRI sign - the molar tooth sign can be seen on this axial image with the roots of the tooth formed by the flipped menisci (red arrowhead) in the intercondylar notch and the crown formed by the intact PCL (yellow arrow).
JOCR-12-79-g003.jpg
PMC9091402_01_JOCR-12-79-g003.jpg
F3
We propose a novel "molar tooth sign" on axial images to assist in identification of this rare entity which necessitates pre-operative identification for appropriate procedural planning (Fig. 3).
Arthroscopic image shows flipped meniscal components - lateral meniscus (red arrowhead), medial meniscus with complex tear anatomy (black arrowhead), and torn remnant ACL fibers (green arrowhead).
JOCR-12-79-g004.jpg
PMC9091402_01_JOCR-12-79-g004.jpg
F4
For the lateral meniscus, the bucket handle component was reduced and repaired using two sharp-shooters by inside-out method (Fig. 4).