A 30-year-old male soccer player presented three years after arthroscopic right anterior cruciate ligament (ACL) repair with complaints of pain and reduced functionality in the right knee. MR imaging obtained on a 3 Tesla scanner showed some fibro-inflammatory tissue on the anterior aspect of the ACL graft and a fissure centered in the femoral trochlear cartilage. Interestingly, a hypo-intense, cord-like structure was visualized running from the posterior horn of the lateral meniscus through the intercondylar notch. On coronal and sagittal images, this structure mimicked a bucket handle tear of the lateral meniscus (double posterior cruciate ligament sign, Fig. A) but if followed closely, passage towards the anterior root of the medial meniscus was noticed. This was best illustrated on the axial images. Preoperative (Fig. B) and postoperative (Fig. C) PD-weighted axial images are shown for comparison. Configuration of the lateral meniscus was normal and no part seemed missing. Some mild degeneration of the posterior horn of the lateral meniscus was present, but no tear was found. The medial meniscus was intact. These findings were compatible with an anatomical variant called the medial oblique menisco - meniscal ligament (OMML). Retrospectively, a much thinner OMML was visible on the preoperative MR images on which the diagnosis of a ruptured ACL was made (Fig. B). Due to postoperative fibrosis, the ligament became thicker and the fibers more separated by hyperintense lines (Fig. C). Coincidentally, the patient recently underwent an MRI examination of the contralateral knee after a soccer injury, where a normal medial OMML was clearly visible.
How to Cite:
Claes H, Pans S. Oblique meniscomeniscal ligament: a potential pitfall in the diagnosis of knee injury. JBR-BTR. 2011;94(4):225. DOI: http://doi.org/10.5334/jbr-btr.655