The knee joint
is made up of three bones: the femur (thigh bone), the tibia (shin bone), and
the patella (knee cap). The joint surfaces of these bones are covered with a
smooth layer called articular cartilage, which glides over each other without
causing any friction.
is a C shaped cartilaginous tissue with a wedge shaped profile that conforms to
the articular surface of bones of the knee joint. There are two menisci in the
knee joint. The one on the inside of the knee joint is called the medial
meniscus and the one on the outer side is called the lateral meniscus.
serve as cushions inside the knee joint. They act as short absorbers and spread
the load evenly within the knee joint and thereby preventing abnormal load on
the articular cartilage. They also assist with the proper movement of the knee
joint and provide stability by keeping the rounded femur surface from sliding
off the flat tibial surface.
The blood supply to the meniscus comes from small blood vessels from the
periphery of the meniscus. Most of the inner meniscal tissue does not have
blood supply (avascular). When there is a tear or damage to the avascular
portion of the meniscus, it does not heal.
The meniscal tear is a result of either traumatic injury (e.g. twisting
injury while playing sports) or degenerative condition. With meniscal tear there is uneven load in the knee joint causing
excessive pressure in certain areas of articular cartilage and can lead to
The commonest clinical presentation of meniscal tear is pain in the
location of meniscal tear associated with swelling. Patients may complain of giving
way, locking or clicking within the knee joint.
Treatment of meniscal tear depends on various factors. The treatment
options are meniscectomy (removing the torn meniscus and trimming the remaining
meniscus), meniscal repair and meniscal replacement with either implant (synthetic)
or transplant (meniscal donor tissue).