The lateral meniscus is one of the two crescent-shaped fibrocartilaginous structures in the knee, with the other being the medial meniscus. These menisci serve as shock absorbers in the knee joint and contribute to its stability.
Location
The lateral meniscus is situated on the tibial plateau’s outer aspect, between the lateral condyle of the femur and the lateral condyle of the tibia.
Structure
- Morphology: The lateral meniscus is more circular in shape compared to the medial meniscus, which is more C-shaped. It is also somewhat smaller and more mobile due to fewer ligamentous attachments.
- Composition: It’s made up of fibrocartilage, which gives it both flexibility and strength. The peripheral border is thick and vascular, while the inner border is thin and avascular.
Function
- Shock Absorption: The menisci, including the lateral meniscus, act as shock absorbers in the knee, cushioning the weight-bearing forces transmitted through the joint.
- Joint Stabilization: By deepening the tibial plateau, the lateral meniscus enhances joint congruity, which helps stabilize the femur on the tibia.
- Lubrication and Nutrition: The menisci play a role in the distribution of synovial fluid within the knee, ensuring proper joint lubrication and nutrition.
- Load Distribution: The menisci help distribute axial load across the knee. Without them, the contact pressure on the articular cartilage would significantly increase, predisposing the joint to early degeneration.
Clinical significance
The clinical significance of the lateral meniscus is profound given its pivotal roles in knee biomechanics and long-term joint health. Injuries to the lateral meniscus, such as tears, are of major concern as they can compromise the shock-absorbing capacity of the knee, leading to increased stress on the articular cartilage. Over time, this can predispose the joint to osteoarthritic changes. The lateral meniscus’s relative mobility, compared to the medial meniscus, may make it less susceptible to certain injuries but can present unique challenges when injured. Partial or complete meniscectomies, surgical procedures where portions of the meniscus are removed, can lead to altered knee biomechanics and accelerate degenerative changes. Conversely, preservation and repair of the lateral meniscus, when feasible, are considered preferable to maintain knee function and delay osteoarthritic progression. Additionally, the lateral meniscus’s involvement in complex knee injuries, like the “terrible triad” which includes injury to the ACL, medial meniscus, and medial collateral ligament, underscores its importance in joint stability and function.
