Case report 85

MR imaging of a meniscal ossicle

“…It is uncertain why patients who do not have a meniscal tear suddenly develop symptoms. Some authors have hypothesized that there can be ossicle growth even in skeletally mature patients and that the focally enlarging meniscus can cause pain by affecting adjacent innervated structures, such as the joint capsule or outer one-third of the meniscus [5,10].…”

“…They usually occur in the posterior horn of the medial meniscus and are associated with meniscal tears [2,5]. Tears probably occur because the ossicle either interferes with normal motion of the meniscus during flexion and extension, or it creates a stress-riser in the meniscus [5,7].…”

“…Meniscal ossicles are an uncommon cause of knee pain [1][2][3]5]. They usually occur in the posterior horn of the medial meniscus and are associated with meniscal tears [2,5].…”

“…They may be asymptomatic, however, and have been found incidentally on knee radiography [2]. Meniscal ossicles are often associated with a meniscal tear, but can cause symptoms without a tear, probably by mass effect from the protruding meniscal contour [5].…”

“…A meniscal ossicle is defined as cortical and cancellous bone with central, viable marrow, all surrounded by meniscal cartilage [5]. They are usually symptomatic and are discovered on plain knee radiographs obtained for pain [1][2][3]5].…”