Anterior lateral meniscofemoral ligament with congenital absence of the ACL.

PURPOSE

to describe agenesis of the anterior cruciate ligament (ACL) with an anterior lateral meniscofemoral ligament.

METHODS AND RESULTS

case report of a 13-year-old girl with an absent ACL and with an anterior lateral meniscofemoral ligament instead, as well as absence of the anterior insertion of the lateral meniscus in the tibia and a discoid ring-like lateral meniscus, with hypoplasia of the lateral femoral condyle. At arthroscopy, the anterior lateral meniscofemoral ligament was found to arise from the anterior horn of the lateral meniscus and insert into the posterolateral aspect of the intercondylar notch, mimicking the course of the native ACL on magnetic resonance imaging (MRI).

CONCLUSION

ACL agenesis may be associated with an anomalous anterior lateral meniscofemoral ligament that may mimic a normal ACL on MRI.