Diagram of meniscal tear patterns

Meniscal injuries can be classified according to their tear patterns. A vertical or longitudinal tear occurs in line with the circumferential fibers of the meniscus . If long enough, this tear is known as a bucket-handle tear. At arthroscopy, the bucket-handle tear may be seen as being attached anteriorly and posteriorly. Alternatively, it may be detached at either end or transected in the middle with unstable anterior and posterior flaps. A bucket-handle tear may displace into the intercondylar notch, where it may cause true locking of the knee joint.

(A) Vertical or longitudinal (Bucket-handle), (B) Flap or Oblique, (C) Radial or Transverse, (D) Horizontal, (E) Complex degenerative.

-Oblique tears are also known as flap or parrot beak tears and are perhaps the most common . These occur generally at the junction of the posterior and middle thirds.

-Radial tears occur in a similar location. They extend from the inner free margin toward the periphery . If such a tear reaches the periphery, it transects the meniscus and renders the hoop stress-distributing capacities of the meniscus useless. Such a tear is the functional equivalent of a total meniscectomy.

-Horizontal cleavage tears usually occur in older individuals. They extend from the inner free margin peripherally to the intrameniscal substance where myxoid degeneration may be present. These tears divide the meniscus into superior and inferior flaps, either of which may be unstable

-Complex degenerative tears occur in older patients. Osteoarthritic changes may be visible on plain radiographs, and chondromalacia of the articular surfaces is commonly encountered. The tears occur in multiple planes .