Answer for BIR CoW 05 Feb 2023
Mucoid degeneration of ACL with ganglion cyst
Findings
Severe anterior cruciate ligament mucoid degeneration with adjoining ganglion cyst in the superomedial aspect. Subchondral cystic degenerative changes in the overlying femoral intercondylar region. Severe osteoarthritis of the knee (Tricompartmental) with femoral / tibial condylar osteophytes. Significant articular cartilage loss over the anteromedial, femoral and tibial condyles. Complex (predominantly radial component) tear of medial meniscus posterior horn extending to body
Discussion
Mucoid degeneration is a rare pathology of ACL and usually affects middle aged individuals with mean age of 42 years. The primary factor for ACL MD seems to be injury to synovial lining The most common and consistent symptom is knee pain, mostly posterior. Hypothetically, it is caused due to mechanical impingement on the PCL and posterior capsule or by causing bone erosions. Knee pain during flexion is probably due to the tightening of the anteromedial bundle The gold standard imaging for the diagnosis of MD of ACL is MRI, which exhibits intermediate signal intensity on T1-weighted and high signal intensity on T2-weighted images. The ACL fibers are usually thick and ill-defined, but the orientation and continuity is usually maintained- this characteristic appearance mimics that of a celery stalk. A celery stalk sign was described the appearance of intact fibers with low signal separated from each other by a prominent high signal within thickened ACL on fat-saturated PD-weighted images. Criteria for a thickened ACL is when the thickness was not uniform and 7 mm or greater. The appearance can mimic acute or chronic interstitial partial tears of the ACL. However, in the case of mucoid degeneration secondary signs of an ACL injury are usually absent. Secondary signs include bone bruising, meniscal tears, anterior subluxation of the tibia and other ligamentous injuries. Ganglion cysts associated with the ACL were defined as fluid signal adjacent to or within the ligament having the following criteria: mass effect on anterior cruciate ligament fibers, lobulated margins, and anterior cruciate ligament fluid disproportionate to joint fluid ACL ganglion cyst appears as fusiform, or rounded, with a clear boundary extending along the course of the ACL or interspersed within the fiber of the ligament. ACL ganglion cyst exhibits hypointense signals on T1 weighted images and hyperintense signals on T2-weighted images.
Findings
Severe anterior cruciate ligament mucoid degeneration with adjoining ganglion cyst in the superomedial aspect. Subchondral cystic degenerative changes in the overlying femoral intercondylar region. Severe osteoarthritis of the knee (Tricompartmental) with femoral / tibial condylar osteophytes. Significant articular cartilage loss over the anteromedial, femoral and tibial condyles. Complex (predominantly radial component) tear of medial meniscus posterior horn extending to body
Discussion
Mucoid degeneration is a rare pathology of ACL and usually affects middle aged individuals with mean age of 42 years. The primary factor for ACL MD seems to be injury to synovial lining The most common and consistent symptom is knee pain, mostly posterior. Hypothetically, it is caused due to mechanical impingement on the PCL and posterior capsule or by causing bone erosions. Knee pain during flexion is probably due to the tightening of the anteromedial bundle The gold standard imaging for the diagnosis of MD of ACL is MRI, which exhibits intermediate signal intensity on T1-weighted and high signal intensity on T2-weighted images. The ACL fibers are usually thick and ill-defined, but the orientation and continuity is usually maintained- this characteristic appearance mimics that of a celery stalk. A celery stalk sign was described the appearance of intact fibers with low signal separated from each other by a prominent high signal within thickened ACL on fat-saturated PD-weighted images. Criteria for a thickened ACL is when the thickness was not uniform and 7 mm or greater. The appearance can mimic acute or chronic interstitial partial tears of the ACL. However, in the case of mucoid degeneration secondary signs of an ACL injury are usually absent. Secondary signs include bone bruising, meniscal tears, anterior subluxation of the tibia and other ligamentous injuries. Ganglion cysts associated with the ACL were defined as fluid signal adjacent to or within the ligament having the following criteria: mass effect on anterior cruciate ligament fibers, lobulated margins, and anterior cruciate ligament fluid disproportionate to joint fluid ACL ganglion cyst appears as fusiform, or rounded, with a clear boundary extending along the course of the ACL or interspersed within the fiber of the ligament. ACL ganglion cyst exhibits hypointense signals on T1 weighted images and hyperintense signals on T2-weighted images.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!