Meniscal Injuries

The menisci, the medial (inner) and the lateral (outer), are two wedge-shaped fibrocartilaginous structures of the knee joint that have the paramount functions of supporting the load transmission between structures, providing shock absorption, and enhancing knee stability by improving the congruency of the joint itself. An interesting feature of the menisci is that the outer parts are more vascularized than the inner, characteristics that become relevant in the management of these injuries. The most common injury mechanisms consist of a twisting motion performed on a semi-flexed knee, often reported during high intensities multi-directional sports (e.g.: soccer, basketball, skiing, etc.). Due to the high-energy twisting mechanisms, patients that injure their knees in this way, tend to report associated ligament injuries, such as Anterior Cruciate ligament and Medial Collateral ligament. Even if less common, meniscal injuries can also occur in forced knee flexion actions, when the patient quickly bends the knees under loaded conditions through a wide range of motions (e.g.: squatting, landing from a fall, lifting heavy weights, etc.). Despite not being the main injury mechanism, low-energy impact injuries are also possible and often reported in older adults, where degenerative changes (e.g.: osteoarthritis) or repetitive stresses (“wear and tear”) might have already contributed to decreasing the meniscal structural tolerance. Meniscal injuries tend to be classified by their injury direction/pattern (horizontal, longitudinal, radial, bucket-handle, flap and complex tears) and each of them presents different specifics and implications for their management. Symptoms of a meniscal tear can significantly vary between subjects depending on the injury mechanisms, associated injuries and type/location of the tear. Common symptomatology includes swelling, pain, clicking, catching and potentially locking with associated inability to flex or extend the knee.