Tag Archive | knee

Arcuate sign – a subtle but important avulsion fracture of the…

Arcuate sign – a subtle but important avulsion fracture of the proximal fibula at the site of arcuate ligament complex insertion. It is associated with cruciate ligament injury in around 90% of cases and represents an unstable posterolateral corner injury. When detected, the arcuate sign should prompt further evaluation with MRI and referral to an orthopaedic surgeon. 

from our tumblr blog

http://radiologysigns.tumblr.com/

Absent bow tie sign – a sagittal MRI knee sign of a displaced…

Absent bow tie sign – a sagittal MRI knee sign of a displaced meniscal tear (often bucket handle type). Normally the second (or even third) image through a meniscus ressembles the appearance of a bow tie with the central portion thinning out towards the inner free edge (left image, third slice of meniscus). When a bow tie is not seen on the second image then the absent bow tie sign is positive (right image) and a search for a displaced meniscus should ensue – by looking for a fragment-in-notch sign or double PCL sign.   

from our tumblr blog

http://radiologysigns.tumblr.com/

Celery stalk sign – describes the appearance of an anterior…

Celery stalk sign – describes the appearance of an anterior cruciate ligament that has undergone mucoid degeneration (a common phenomenon). Its low signal longitudinal fibers are separated from each other by higher signal mucinous material simulating the appearance of celery. It is important to differentiate mucoid degeneration from ACL tear where there will be high signal but absent or disrupted low signal fibres.   

from our tumblr blog

http://radiologysigns.tumblr.com/

Lipohaemarthrosis – literally means fat and blood within a…

Lipohaemarthrosis – literally means fat and blood within a joint. Its presence implies an intra-articular fracture with marrow fat having leaked out into the joint. Because fat is less dense than blood it separates on top creating a perfectly straight line known as the FBI sign (Fat-Blood Interface). The sign is best seen on lateral horizontal beam images of the knee within the suprapatellar pouch. The above patient has a tibial plateau fracture

from our tumblr blog

http://radiologysigns.tumblr.com/

Segond fracture – small avulsed bone fragment from the lateral…

Segond fracture – small avulsed bone fragment from the lateral margin of the tibial plateau. Avulsion at this location is the result of excessive varus stress on the lateral joint capsule. It is a small but important fracture as it has a very high association with internal derangement of the knee, particularly anterior cruciate ligament tear (right image) which is present in more than 75% of cases.

from our tumblr blog: http://radiologysigns.tumblr.com/post/24998960885

http://radiologysigns.tumblr.com/