[The "empty" cruciate ligament notch. Aplasia or trauma aftereffect?].

Discoligamentary injuries of the knee frequently lead to an arthroscopic inspection of the joint. We present a case in which after two traumatic events a mensal tear and an empty notch were found on arthroscopic examination. The differential diagnosis of congenital aplasia of the anterior cruciate ligament (CAACL) versus neglected rupture of the ACL is discussed.