Case Of the Week (COW) 06 September 2015
MENISCAL TEAR WITH PARAMENISCAL FLUID COLLECTION
Findings:
Horizontal cleavage tear of medial meniscus posterior horn with large parameniscal cystic fluid collection noted. Medial collateral ligament bursal distension is also present. Moderate osteoarthritis of the knee noted. Significant cartilage loss noted over the patellar trochlea with subchondral edema.
Discussion:
Meniscal tears are the failure of the fibrocartilaginous menisci of the knee. Acute meniscal tears occur after rotatory trauma of the knee, whereas chronic degenerative meniscal tears often occur in the elderly after minimal rotatory trauma or stress on the knee. Meniscal tear types include horizontal tear (cleavage tear): parallel to the tibial plateau longitudinal tear: perpendicular to the tibial plateau; parallel to the long axis of the meniscus radial tear: perpendicular to the tibial plateau and the long axis of the meniscus complex tear: combination of all or some of horizontal, longitudinal and radial-type years displaced tear: tear involving component that is displaced, either still attached to the parent meniscus or detached: flap tear: displaced horizontal or longitudinal tears bucket-handle tear: displaced longitudinal tear parrot beak tear: displaced radial tear root tear: often a radial-type tear located at the meniscal root Two basic MR characteristics of meniscal tears : 1) high intrameniscal signal extending to at least one (if not both) articular surfaces on two slices (do not have to be contiguous, e.g. sagittal and coronal slices) 2)distortion of the normal meniscal morphology if no prior surgery GRADING grade 1: small focal area of hyperintensity, no extension to the articular surface grade 2: linear areas of hyperintensity, no extension to the articular surface 2a: linear abnormal hyperintensity with no extension to the articular surface 2b: abnormal hyperintensity reaches the articular surface on a single image 2c: globular wedge-shaped abnormal hyperintensity with no extension to the articular surface Grade 2 tears were found to be associated with a meniscal tear on arthroscopy. Therefore, they were subdivided into 2a, 2b, and 2c. Dillon et al. said that 50% of patients with grade 2c had meniscal tears on arthroscopy. grade 3: abnormal hyperintensity extends to at least one articular surface (superior or inferior), and is referred as a definite meniscal tear Associated features that are suggestive of a meniscal tear include : tibial subchondral bone oedema parameniscal cyst.
Contributed By:
Prof. S Babu Peter, Dr. S. Arunprasad
Barnard Institute of Radiology
MENISCAL TEAR WITH PARAMENISCAL FLUID COLLECTION
Findings:
Horizontal cleavage tear of medial meniscus posterior horn with large parameniscal cystic fluid collection noted. Medial collateral ligament bursal distension is also present. Moderate osteoarthritis of the knee noted. Significant cartilage loss noted over the patellar trochlea with subchondral edema.
Discussion:
Meniscal tears are the failure of the fibrocartilaginous menisci of the knee. Acute meniscal tears occur after rotatory trauma of the knee, whereas chronic degenerative meniscal tears often occur in the elderly after minimal rotatory trauma or stress on the knee. Meniscal tear types include horizontal tear (cleavage tear): parallel to the tibial plateau longitudinal tear: perpendicular to the tibial plateau; parallel to the long axis of the meniscus radial tear: perpendicular to the tibial plateau and the long axis of the meniscus complex tear: combination of all or some of horizontal, longitudinal and radial-type years displaced tear: tear involving component that is displaced, either still attached to the parent meniscus or detached: flap tear: displaced horizontal or longitudinal tears bucket-handle tear: displaced longitudinal tear parrot beak tear: displaced radial tear root tear: often a radial-type tear located at the meniscal root Two basic MR characteristics of meniscal tears : 1) high intrameniscal signal extending to at least one (if not both) articular surfaces on two slices (do not have to be contiguous, e.g. sagittal and coronal slices) 2)distortion of the normal meniscal morphology if no prior surgery GRADING grade 1: small focal area of hyperintensity, no extension to the articular surface grade 2: linear areas of hyperintensity, no extension to the articular surface 2a: linear abnormal hyperintensity with no extension to the articular surface 2b: abnormal hyperintensity reaches the articular surface on a single image 2c: globular wedge-shaped abnormal hyperintensity with no extension to the articular surface Grade 2 tears were found to be associated with a meniscal tear on arthroscopy. Therefore, they were subdivided into 2a, 2b, and 2c. Dillon et al. said that 50% of patients with grade 2c had meniscal tears on arthroscopy. grade 3: abnormal hyperintensity extends to at least one articular surface (superior or inferior), and is referred as a definite meniscal tear Associated features that are suggestive of a meniscal tear include : tibial subchondral bone oedema parameniscal cyst.
Contributed By:
Prof. S Babu Peter, Dr. S. Arunprasad
Barnard Institute of Radiology