What is the knee meniscus?

The menisci are crescent-shaped cartilaginous structures located between the femur (thigh bone) and tibia (shin bone) in the knee joint. There are two menisci in the knee, the medial (inner) and lateral (outer), both having a C-shaped configuration, with their anterior and posterior ends attached to the tibia. The shape of the menisci helps reduce the incongruity between the articular surfaces of the femur and tibia, increasing the contact area of the joint surfaces. They contribute to load transmission, reduce pressure on the articular cartilage, and play a role in knee stability and the distribution of synovial fluid within the knee. At birth, the entire meniscus has blood vessels, but by the age of ten, the blood supply to the inner two-thirds of the meniscus ceases, while the outer third continues to receive blood vessels, enhancing its potential for healing after injury. Previously, it was believed that all meniscal injuries in children were associated with a discoid shape. However, nowadays, an increasing number of athletic children present to the pediatric orthopedic clinic with tears in a normal-shaped meniscus. Meniscal tears are often associated with anterior cruciate ligament (ACL) injuries. Moreover, a meniscal tear compromises its physiological “protective” function, initiating unfavorable processes in the knee, predominantly cartilage damage leading to gradual degenerative changes or knee osteoarthritis.

How to diagnose a meniscal tear in children?

A meniscal tear is the most common knee injury, constituting almost 75% of the total intra-articular knee pathology. The clinical presentation of an acute meniscal injury is characterized by intense pain over the injured meniscus, swelling, and a reduced range of motion. Children often describe sudden, severe pain around the knee when turning or extending the leg from a semi-bent position. Additionally, a potential clinical manifestation of an acute meniscal injury is the occurrence of knee locking, the inability to achieve full mobility due to the entrapment of a torn meniscal fragment between the knee bones. When a meniscal injury is accompanied by an ACL tear, the event of injury is more dramatic, and children describe a “popping out” of the knee. Clinical suspicion of a meniscal injury is further confirmed when specific tests for meniscal damage yield positive results. All meniscal tests involve compression and rotation in the knee to provoke tenderness. The presence of joint effusion is not uncommon, along with a limitation of full mobility. Every injured knee should undergo X-ray imaging in at least two projections to assess bone condition. Since menisci are not visible on X-rays, magnetic resonance imaging (MRI) is the preferred imaging modality to demonstrate a damaged meniscus. MR images clearly reveal the sites of tears after analysis. There are two characteristic meniscal injuries: RAMP (posterior horn of the medial meniscus) and ROOT (meniscal root) lesions. A RAMP lesion represents a special form of the rupture of the posterior part of the inner meniscus in the area of its connection to the joint capsule. RAMP lesions are often associated with ACL rupture, and they are challenging to detect, earning them the name “hidden meniscal lesions.” A ROOT lesion is an injury to the meniscal root, involving the rupture of the threads connecting the meniscus ends to the tibia. Functionally and biomechanically, such a meniscus no longer distributes force correctly, significantly increasing the contact pressure between the tibia and femur.

How to treat a meniscal tear in children?

The current surgical method for meniscal tears is knee arthroscopy with meniscus repair. Arthroscopic meniscus repair begins with an inspection inside the joint and confirmation of the meniscal injury. Once the meniscal tear is identified, the rupture’s characteristics are determined, and stability inspection is performed using palpation. The operating surgeon then decides which operative technique to apply for meniscus repair. Before actual meniscus repair, it is necessary to freshen up the meniscus or joint capsule edges, especially in older tears, to initiate biological tissue healing processes. This operative technique should always be applied when treating meniscal tears in children and adolescents, as meniscectomy (meniscus removal) in this age group is considered unprofessional treatment. During meniscus repair, skin incisions on the knee may sometimes be made to suture the meniscus threads to the joint capsule. After meniscal surgery, rehabilitation is crucial to enable meniscus healing while preserving range of motion and muscle strength, aiming for a child’s return to activities at the same level as before the injury. Squatting, kneeling, and knee rotations are prohibited in the early stages of rehabilitation. Gradual implementation of physical therapy achieves readiness for sports activities around six months after surgery.

Scroll to Top