A unique case of anterior cruciate ligament rupture coexisting with asymptomatic tear of discoid medial meniscus: A case report.

INTRODUCTION: Anterior cruciate ligament (ACL) is among the most commonly injured structure in the knee with some also suffering from meniscus injuries. However, an ACL rupture with concomitant injury of the discoid medial meniscus is a very uncommon.

PRESENTATION OF CASE: A 30 years-old male patient came with unstable left knee, with no history of locked knee and tender joint line. The Lachman and anterior drawer test were positive with no sign of meniscus involvement. The Magnetic Resonance Imaging (MRI) result revealed ACL rupture and a double PCL sign suggesting a medial meniscus tear. Arthroscopic knee surgery was performed for partial meniscectomy of the torn discoid medial meniscus followed by ACL reconstruction, followed by rehabilitation protocol. Six months after the procedure, patient was able to return to preinjury activities.

DISCUSSION: Discoid meniscus of the knee is a rare congenital condition, especially at the medial meniscus. Due to its shape, it distributes the stress differently and therefore more prone to injury. Patients may present with complains of medial knee pain, iterative effusion, locking in flexion. Surgical management is appropriate for a torn discoid medial meniscus with type of surgery depends on each case. A bucket-handle type of injury with torn ACL should be managed by meniscectomy followed by ACL reconstruction.

CONCLUSION: A proper diagnosis of ACL rupture and meniscus injury using arthroscopy is a must. A combination of partial meniscectomy of torn discoid meniscus and ACL reconstruction prevents impingement of the graft therefore reducing the risk of graft failure.