The medial meniscus is one of the two semi-circular fibrocartilaginous structures in the knee, the other being the lateral meniscus. These menisci play crucial roles in stabilizing the knee joint, distributing weight, and reducing friction during movement.
Location
Situated on the inner aspect of the tibial plateau, the medial meniscus lies between the medial condyle of the femur and the medial condyle of the tibia.
Structure
- Morphology: Unlike the more circular lateral meniscus, the medial meniscus is C-shaped. It is broader posteriorly than anteriorly.
- Composition: Comprised of fibrocartilage, it is both flexible and tough. The outer, peripheral border is thick and somewhat vascular, whereas the inner border, facing the joint, is thin and largely avascular.
- Attachments: It is more firmly attached than the lateral meniscus, particularly due to its connection with the deep medial collateral ligament, limiting its mobility.
Function
- Shock Absorption: It acts as a cushion, helping to absorb and distribute forces across the knee joint during weight-bearing activities.
- Joint Stabilization: By deepening the tibial plateau, it provides added stability to the femur-tibia articulation.
- Lubrication and Nutrition: Helps in distributing synovial fluid in the knee, promoting joint lubrication and nourishing the articular cartilage.
- Load Distribution: Spreads out compressive forces over a wider area, protecting the articular cartilage from excessive wear and potential damage.
Clinical significance
The medial meniscus holds substantial clinical relevance due to its integral role in knee joint biomechanics. Being more rigidly attached than its lateral counterpart, it is more prone to injury, particularly during movements that combine compression and rotation of the knee. Tears or damages to the medial meniscus can compromise the joint’s weight distribution capability, leading to increased pressure on the articular cartilage. Over time, this abnormal stress can expedite the onset of osteoarthritic changes in the knee. Additionally, because of its connection to the medial collateral ligament, injuries to the medial meniscus often coexist with other ligamentous injuries. The repair versus removal decision during surgical interventions is pivotal; while removal (meniscectomy) can provide short-term relief, it might accelerate degenerative changes in the long run. On the other hand, successful meniscus repair can potentially preserve knee function and decelerate the progression towards osteoarthritis. In clinical practice, the state and function of the medial meniscus are continually evaluated during diagnostic processes, rehabilitation protocols, and surgical planning, underscoring its significance in orthopedics.
