The menisci are crescent-shaped, fibrocartilaginous structures that are triangular in cross section. They are composed predominantly of type 1 collagen. Only the peripheral 20-30% of the medial meniscus and 10-25% of the lateral meniscus are vascularized. These structures deepen the articular surfaces of the tibial plateau and have a role in stability, lubrication, and nutrition.
Are the most common injury to the knee that requires surgery. The medial meniscus is torn approximately three times more often than the lateral meniscus. Traumatic meniscal tears are common in young patients with sports-related injuries. Degenerative tears usually occur in older patients
In the absence of intermittent swelling, catching, locking, or giving way, meniscal tears, particularly those degenerative in nature, may be treated conservatively. Younger patients with acute tears, tears causing mechanical symptoms, and those that fail to improve with conservative measures may benefit from operative treatment. (partial meniscectomy or meniscal repair)
Discoid menisci (“popping knee syndrome”)
Patients may develop mechanical symptoms, or “popping,” with the knee in extension. MRI can be helpful and may also demonstrate associated tears. Treatment varies.