Meniscus Disorders, Knee

History: In younger individuals, there is usually a history of trauma. The individual may recall feeling a popping or snapping sensation when the trauma occurred. In older individuals, the trauma may be nonspecific, such as repeated squatting or kneeling. The individual may complain of knee pain, swelling, limited range of motion, and a clicking sound. Locking (an inability to straighten the knee) or buckling (a sudden giving way of the knee) may occur.

Physical exam: The exam may reveal tenderness over the medial or lateral joint line of the knee. There may be evidence of fluid buildup (effusion) in the joint. Squatting may cause pain. Tests that apply rotational and axial compression forces to the knee (such as Apley's compression test or McMurray's test) often reveal a palpable click or localized pain suggestive of meniscal injury.

Tests: Plain x-rays are not diagnostic but can rule out fracture, arthritis, and most loose bodies. MRI is a non-invasive method of evaluating the condition of the menisci and is the standard imaging method used. On MRI, the menisci of older individuals may show evidence of aging that is not related to injury. Individuals who cannot undergo MRI testing may be evaluated by an arthrogram (x-rays taken after dye is injected into the joint) or CT arthrogram. The interior of the joint can be examined directly by exploratory arthroscopy, the insertion of a very small viewing scope (arthroscope) into the knee joint through a small surgical opening. The diagnostic accuracy, sensitivity, and specificity of arthroscopy approach 100% (Baker). If indicated, arthroscopic surgery to trim or repair a meniscal tear may be performed at the same time.