Fragment-in-notch sign (knee)
The fragment-in-notch sign is closely related to, can be thought of as a failed, double PCL sign, in so far as it represents a meniscal fragment lying in the intercondylar notch, but not paralleling the posterior cruciate ligament (PCL).
Although both signs are most frequently seen in the setting of a bucket handle tear, in contrast to double PCL signs is usually due to a medial meniscal tear, the fragment-in-notch sign is more commonly seen with lateral meniscal bucket handle tears 1. This no doubt is largely due to the anterior cruciate which aids medial fragments aligning with the PCL whereas it impedes lateral fragments from doing so 1.
The sign may also bee seen with flipped tears and free fragments.
- 1. Ruff, C, Weingardt, JP, Russ, PD, Kilcoyne, RF "MR imaging patterns of displaced meniscus injuries of the knee" Am. J. Roentgenol. 1998 170: 63-67
- 2. Camacho Marc A. “The Double Posterior Cruciate Ligament Sign1.” Radiology 233, no. 2 (November 2004): 503-504. doi:10.1148/radiol.2332020945.