summary Meniscal tears are common sports-related injuries in young athletes and can also present as a degenerative condition in older patients. Diagnosis can be suspected clinically with joint line tenderness and a positive McMurray's test, and can be confirmed with MRI studies. Treatment can be nonoperative versus operative (partial meniscectomy versus repair) depending on the morphology of the meniscus tear, root involvement, patient symptoms, and patient activity demands. Epidemiology Incidence very common most common indication for knee surgery Risk factor higher risk in ACL deficient knees Etiology Pathophysiology medial tears more common than lateral tears login to view 1 more bullet degenerative tears in older patients usually occur in the posterior horn medial meniscus lateral tears more common in acute ACL tears Anatomy Anatomy of meniscus Classification Descriptive classification location red zone (outer third, vascularized) red-white zone (middle third) white zone (inner third, avascular) position (anterior, middle, posterior third, root) size pattern vertical/longitudinal login to view 2 more bullets bucket handle login to view 1 more bullet oblique/flap/parrot beak login to view 1 more bullet radial login to view 1 more bullet horizontal login to view 2 more bullets complex root login to view 4 more bullets Presentation Symptoms pain localizing to medial or lateral side mechanical symptoms (locking and clicking), especially with squatting delayed or intermittent swelling Physical exam joint line tenderness is the most sensitive physical examination finding effusion provocative tests Apley compression login to view 1 more bullet Thessaly test login to view 1 more bullet McMurray's test login to view 2 more bullets Imaging Radiographs Should be normal in young patients with an acute meniscal injury Meniscal calcifications may be seen in crystalline arthropathy (ex. CPPD) MRI indications MRI is most sensitive diagnostic test, but also has a high false positive rate findings MRI grade III signal is indicative of a tear login to view 1 more bullet parameniscal cyst indicates the presence of a meniscal tear bucket handle meniscal tears indicated by login to view 2 more bullets meniscal extrusion or "ghost sign," may indicate meniscal root tear MCL sprain pain with valgus stress at 30° knee flexion, which isolates the superficial MCL gapping of medial joint line Plica syndrome pain is typically in the medial parapatellar region may have palpable medial parapatellar cord Osteochondral lesions may present very similarly differentiated with imaging (MRI) Treatment Nonoperative rest, NSAIDS, rehabilitation indications login to view 1 more bullet outcomes login to view 2 more bullets Operative partial meniscectomy indications login to view 2 more bullets outcomes login to view 7 more bullets meniscal repair indications login to view 13 more bullets outcomes login to view 4 more bullets meniscal transplantation indications login to view 2 more bullets contraindications login to view 6 more bullets outcomes login to view 6 more bullets total meniscectomy of historical interest only outcomes login to view 3 more bullets Techniques Rest, NSAIDS, rehabilitation technique PWB, ROM as tolerated Partial Meniscectomy approach standard arthroscopic approach technique minimize resection (DJD proportional to amount removed) do not use thermal (heat probes) postoperative early active range of motion prolonged immobilization (10 weeks) is detrimental to healing in a dog model Meniscal repair approach inside-out technique login to view 8 more bullets all-inside technique (suture devices with plastic or bioabsorbable anchors) login to view 3 more bullets outside-in repair login to view 1 more bullet open repair login to view 1 more bullet technique vertical mattress sutures are strongest because they capture circumferential fibers healing is enhanced by rasping knee flexion beyond 90 degrees should be avoided postoperatively risks saphenous nerve and vein (medial approach) peroneal nerve (lateral approach) popliteal vessels Meniscal Transplantation technique bone to bone healing with plugs at each horn or a bridge between horns peripheral vertical mattress sutures correct sizing of the allograft is essential (commonly based on radiographs, within 5-10% error tolerated) login to view 2 more bullets Complications Saphenous neuropathy (7%) Arthrofibrosis (6%) Sterile effusion (2%) Peroneal neuropathy (1%) Superficial infection (1%) Deep infection (1%)