Meniscus, also called semi-lunar cartilage (rubber-like padding around bones where they join together), is knee-joint cartilage which grows inward from the joint capsule and forms pads or discs. These discs are situated within the knee to cushion the contact between femur (the bone of upper leg) and tibia (the biggest bone of the lower leg). They deepen tibia’s surface and provide a larger and more stable surface area for the femur to join with. Their function is shock absorption, reducing friction, and stabilization of the knee joint.
Half of all knee ligament and meniscal injuries are sports injuries. There are chronic and acute meniscal tears. Chronic degenerative tears rarely cause any dysfunction or pain since they are caused by many episodes of minimal trauma. When constant shearing forces act on the inner meniscus, it may lead to detachment, pain, instability, and momentary locking. Horizontal cleavage tears are chronic in nature and are due to degenerative changes in the back inner part of the knee.
The three acute tears are: longitudinal, bucket-handle, and parrot-beak, and are classified by their shape. The most common are longitudinal tears and happen when the knee is twisted while flexed and the foot is fixed in one place. Bucket-handle tears have 40% frequency of incidence. They happen when an entire longitudinal segment of meniscus is displaced toward the center of the tibia, often leading to the knee locking in place when flexed. Parrot-beak tears are often found in adolescents and involve the mid-outer meniscus developing two tears in a parrot-beak shape.
Immediate treatment includes RICE (rest, ice, compression, elevation), non-steroidal anti-inflammatory medications (NSAIDs), and crutches to keep the weight off the injured knee. See your family health professional immediately if the knee is locked in place or if excessive joint effusion (abnormal accumulation of fluid in a joint) is present. Physiotherapy, surgery, and/or orthoses (braces or other devices that support and correct joint alignment) may be prescribed by family doctor or nurse practitioner.