Age / Sex : 40 / M

Chief complaint: knee pain after falling-down

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)

Courtesy: 추혜정(Hye Jung Choo), 인제대부산백병원(Inje University Pusan Baik Hospital)

Anomalous insertion of medial meniscus into the anterior cruciate ligament

Discussion

Findings: A linear dark signal
intense band arises from anterior horn of medial meniscus and runs parallel to
the anterior cruciate ligament. The contusion of the lateral discoid meniscus,
tear of the medial medial meniscus, and fracture at the medial femoral condyle
are also noted.  

Differential Diagnosis: infrapatellar plica, partial tear of anterior cruciate
ligament

Diagnosis:
 Anomalous insertion of medial meniscus

Discussion:

Anomalous
insertion of medial meniscus into the anterior cruciate ligament

Incidence:
1.2%~2.26%

MR feature :
Linear band with T2 low signal intensity running parallel to the ACL

Combined
anomaly

-       Medial discoid meniscus: 7%

-       Lateral discoid meniscus: 13%

(About 6% in the cases of lateral discoid meniscus had the
anomalous insertion of the medial meniscus into the ACL)

-       Absence transverse ligament: 42%~
50%

Controversy
as to whether anomalous insertion of medial meniscus can lead to clinical
problems

References: Anomalous insertion of the medial
meniscus into the anterior cruciate ligament: the MR appearance. British J Radiol
81 (2008), 20–24