Snapshot A 25-year-old woman twisted and injured her right knee during a soccer game 4 weeks ago. At that time, there was moderate knee swelling which has since resolved. She reports intermittent medial right knee pain and a sensation of the joint giving way since then. Her symptoms are aggravated by twisting or squatting. On physical exam, there is a mild effusion, medial joint line tenderness, and a positive medial McMurray test. Valgus stress reveals no pain or joint opening. Anterior and posterior drawer test is negative. Introduction Clinical definition a knee injury caused by meniscal tears, categorized into two types acute meniscus tear age-related degeneration of meniscus part of the "terrible triad" anterior cruciate ligament tear medial collateral ligament tear meniscus tear Associated conditions > 30% associated with anterior cruciate ligament injury Epidemiology Demographics male > female < 40 years of age are more likely to have acute tears > 40 years of age are more likely to have degenerative tears medial meniscus tears are more common than lateral meniscus tears due to decreased mobility of the medial meniscus as it attaches to the MCL Location menisci are located between the femoral condyles and tibial plateau Risk factors acute tears sports degenerative tears older age male gender work-related use of knee (kneeling, squatting, and stair climbing) obesity ETIOLOGY Pathogenesis two most common mechanisms non-contact trauma from twisting of the knee or sudden acceleration and directional change, often in the context of sports contact injury with varus or valgus forces on the knee repetitive normal forces from age-related degeneration menisci are less compliant with increasing age Presentation Symptoms persistent joint pain after inciting event (acute tears) insidious onset of knee pain (degenerative tears) locking, popping, or catching of the knee during ambulation pain during ambulation, especially with climbing stairs sensation of joint giving way Physical exam knee effusion and swelling that worsens with activity more common with acute injuries knee pain that worsens with motion, especially with deep knee flexion impaired range of motion focal joint tenderness normal patellar tracking positive Thessaly test standing with the knee flexed to 20 degrees, have the patient twist to externally and internally rotate the leg discomfort or mechanical symptoms is a positive test positive McMurray test for medial meniscus tear flex the knee and palpate medial side of the knee externally rotate the leg and bring the knee into extension palpable pop or click is a positive test for lateral meniscus tear flex the knee and palpate lateral side of the knee internally rotate the leg and bring the knee into extension palpable pop or click is a positive test Imaging Radiograph indications to rule out other bony pathologies findings typically normal may show secondary findings such as joint effusion Magnetic resonance imaging indications to confirm a meniscus tear when the diagnosis is unclear findings hyperintense signal inside the meniscus Studies Making the diagnosis most cases are clinically diagnosed Differential Anterior or posterior cruciate ligament injury distinguishing factor positive drawer sign Osteoarthritis of the knee distinguishing factor no diffusion present joint stiffness is typically present Treatment Management approach meniscal tears can be managed conservatively or with surgery and depends on various patient factors, including the patient’s age, the presence of comorbidities, and extent of the tear Conservative conservative treatment indications degenerative tears asymptomatic tears patients with multiple comorbidities and poor surgical candidates modalities rest and ice use of crutches knee sleeves physical therapy Medical nonsteroidal anti-inflammatory drugs indications pain management Operative arthroscopic repair indications symptomatic tears failure of conservative management surgeries partial meniscectomy meniscal repair Complications Fibrosis Septic arthritis