Tears of the meniscus can occur in all age groups. The meniscus is a crescent-shaped fibrocartilaginous structure that is found between the femur and the tibia within the knee joint. The menisci are shock absorbers and contribute to knee stability, as well. Meniscus injuries may occur in isolation or occur in combination with other injuries. The medial (inner) meniscus is torn more commonly than the lateral meniscus, however, the lateral (outer) meniscus is more likely to tear in the setting of an acute ACL injury.
Anatomy and Classification
Meniscal tears are described by their location, size and pattern. The outer third of the meniscus is vascularized, while the inner third is avascular. Vascular areas are more amenable to meniscus repairs and have better healing potential following surgery.
Physical Examination and Work-up
On presentation, an effusion of the knee joint may be present. Pain is often along the joint line and is reproduced with deep knee flexion. Mechanical symptoms of locking, catching or clicking may occur with activity.
McMurray Test:
this clinical test is used to assess for the presence of a meniscus injury. With the patient lying on their back, the examiner holds the sole of the foot with one hand and palpates the joint line of the knee. The knee is extended and externally rotated with valgus stress to assess the medial meniscus. The test is repeated with the examiner extending the knee and internally rotating the tibia with varus stress. A positive test is pain at the joint line or a palpable clock at the joint line during the manuever.
Radiology
In addition to physical examination, X-rays assist in assessing for meniscal calcification (crystalline arthropathy). An MRI may be ordered to confirm the diagnosis and characterize a tear if present.
Management of Meniscus Tears
Non-operative care includes rest, NSAIDs, physical therapy, and injections are the first line of treatment for degenerative tears. Arthroscopy surgery, either partial meniscectomy or meniscal repair, is recommended after failure of non-operative management or in the setting of tears amenable to repair.
Post-operative rehabilitation weight bearing status is determined by the specific surgical procedure. Those undergoing partial meniscectomy may weight bear immediately, while those undergoing meniscal repair require a period of non-weight bearing to allow for healing. In either case, physical therapy begins immediately to assist with edema control, to reduce quadriceps atrophy and promote range of motion.
