{"id":1475,"date":"2024-03-12T16:56:07","date_gmt":"2024-03-12T20:56:07","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/?post_type=chapter&p=1475"},"modified":"2025-10-17T19:31:06","modified_gmt":"2025-10-17T23:31:06","slug":"menisci-tears","status":"web-only","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/pathophysiology\/chapter\/menisci-tears\/","title":{"raw":"Menisci Tears","rendered":"Menisci Tears"},"content":{"raw":"

Meniscus<\/strong><\/h3>\r\nThe knee joint contains two menisci (sing.: meniscus), which are crescent-shaped fibrocartilage structures composed largely of collagen, fibroblasts and chondrocytes.\u00a0 The collagen is arranged in longitudinal, circumferential bundles and also interwoven in radial and oblique directions to withstand force.\u00a0 Meniscus is derived from the Ancient Greek word miniskos meaning \u2018crescent\u2019.\u00a0 Menisci are also found in the wrist, acromioclavicular, sternoclavicular and temporomandibular joints and play key roles in joint stability.\u00a0 Each knee contains a lateral and a medial meniscus, that unlike articular discs, cover only part of the articulating bones, but similarly provide structural support.\u00a0 Mensci reduce friction, support load, absorb shock, guide range of motion, and provide proprioception.\u00a0 Menisci are wedge shaped and composed of \u201cred\u201d and \u201cwhite\u201d cartilage, with the red outer portion being more vascularized than the white portion and therefore more adept at healing.\u00a0 It has been found that vascular perfusion diminishes after the age of 40.\u00a0 Nerve endings within the menisci are thought to play a role in providing sensory feedback and proprioception.\r\n\r\n \r\n\r\n[caption id=\"attachment_1745\" align=\"alignnone\" width=\"300\"]\"Menisci\"<\/a> (a) Schematic representation of the right knee showing the position of the menisci. (b) Schematic representation of the lateral meniscus\u2019 shape[\/caption]\r\n

Meniscus Tears<\/strong><\/h3>\r\nAcute meniscus tears are often due to sport injuries or trauma, whereas chronic or degenerative meniscus tears or damage occur due to prolonged wear-and-tear.\u00a0 Acute tears can occur during sudden twisting or squatting movements.\u00a0 Tears are classified based on their appearance and direction of tear, for example: longitudinal (which may take the shape of a bucket handle), radial, horizontal, oblique flap (or parrot-beak), or root tears.\r\n
<\/div>\r\n\r\n[caption id=\"attachment_1747\" align=\"alignnone\" width=\"300\"]\"Representation<\/a> Representation of all meniscal tear patterns.[\/caption]\r\n

Risk Factors - Meniscus Tears<\/strong><\/h3>\r\nAthletes involved in aggressive sports are most at risk and currently meniscal injuries occur most often in young males during sports (e.g., football, skiing, and volleyball).\u00a0 The second most common cause is due to degenerative damage and is observed most frequently in individuals older than 55 years old.\r\n

Risk Factors - Meniscus Tears<\/strong><\/h3>\r\nAthletes involved in aggressive sports are most at risk and meniscal injuries occur most often in young males during sports.\u00a0 The second most common cause is due to degenerative damage and is observed most frequently in individuals older than 55 years old.\r\n

Pathogenesis - Meniscus Tears<\/strong><\/h3>\r\nAn acute tear will become inflamed and joint effusion will develop within a few hours.\u00a0 Locking of the joint may occur if pieces of the meniscus impede joint movement.\u00a0 Tears to the red (vascularized) zone are better at healing that tears to the white (non-vascularized) zones.\u00a0 The extent of healing depends on the location of the tear, as well as the overall health of the individual and availability of supportive treatments.\r\n

Signs and Symptoms - Meniscus Tears<\/strong><\/h3>\r\nAcute meniscus tears are typically accompanied by joint pain, in addition to loss of joint stability and possibly locking (loss of range motion), and\/or clicking sounds.\u00a0 An individual may limp and exhibit signs of joint tenderness, difficulty squatting and\/or extending knee.\r\n

Diagnostic Tests - Meniscus Tears<\/strong><\/h3>\r\nA physical examination may be followed up by analysis of effusion using arthrocentesis.\u00a0 Fluid is analyzed for blood, bacteria, glucose, protein and cells.\u00a0 Arthrocentesis can also be used to drain excess effusion.\u00a0 Imaging (e.g., x-ray, arthrography, MRI) are used to assess the tear and any other damage as well as rule out fractures and arthritis.\u00a0 Imaging plays an important role in determining treatment options. Arthroscopy can be used during assessment and treatment.\r\n\r\n[caption id=\"attachment_1754\" align=\"alignnone\" width=\"300\"]\""Knee<\/a> \"Knee MR imaging of types of meniscal tears. A: longitudinal tear. The sagittal FS PD-weighted image of a 25-year-old male shows a peripheral longitudinal tear of the LM posterior horn, also known as a Wrisberg tear (white arrow). B-C: horizontal tear. Coronal and sagittal FS PD-weighted image, respectively, of a 30-year-old woman, shows a horizontal tear of the MM body and posterior horn (white arrow), contacting the inferior articular surface (white arrow in C), with extrusion and a displaced fragment extending to the tibial-meniscus recess (yellow arrow). D-E: radial tear. Sagittal and axial FS PD-weighted image, respectively, of a 19-year-old male, shows a vertically oriented cleft (white arrow) involving the LM at the junction of the body and anterior horn and the oblique course of the radial tear (white arrow in E) with respect to the sagittal plane. F: complex tear. Sagittal FS PD-weighted image of an 18-year-old male shows horizontal (white arrow) and vertical (yellow arrow) components of a MM complex tear.\"[\/caption]\r\n

Treatment - Meniscus Tears<\/strong><\/h3>\r\nThe use of PRICE (Protection, Rest, Ice, Compression, and Elevation) can help alleviate swelling and pain.\u00a0 Anti Inflammatory medications (e.g., NSAIDs), analgesics (e.g., Tylenol) and corticosteroid injections may be recommended.\r\n\r\nWhile some meniscal tears heal without intervention, most tears require surgical treatment.\u00a0 Surgery is performed to either prevent the tear from becoming larger, or to remove pieces that may cause locking or increase the risk of developing arthritis.\u00a0 Treatment depends on the location, type of tear, extent of damage, age and activity levels of the individual, and may involve meniscectomy or repair of meniscus.\u00a0 Treatment goals are to restore pain-free movement, enable physical activity, and prevent muscular atrophy.\u00a0 Physical therapy and the use of stretching and strength building exercises play an important role in rehabilitation enhancing the quality of life and return to sport.\r\n\r\nIn addition to prescribed rehabilitative and progressive exercises, therapies such as transcutaneous electrical nerve stimulation (TENS) may be used as well as massage.\r\n\r\n \r\n\r\n[caption id=\"attachment_1753\" align=\"alignnone\" width=\"300\"]\""Surgical<\/a> \"Surgical procedures of arthroscopic meniscoplasty. (A) The patients were placed in a supine position, and the standard anterolateral and anteromedial arthroscopic portals were established. (B) With the assistance of the probe hook, the knee was examined thoroughly to confirm the torn position and shape of the DLM. (C) The torn and hypertrophic parts of DLM were removed by basket forceps. (D) DLM was trimmed into \"C\" shape, and the edge of the meniscus with a width of at least 5 to 6 mm was cautiously retained. DLM = discoid lateral meniscus.\"[\/caption]\r\n

Prevention - Meniscus Tears<\/strong><\/h3>\r\nPrevention strategies include strengthening supporting muscles, as well as wearing supportive shoes designed for the sport or activity that one is participating in.\u00a0 Additionally, a healthy diet and lifestyle, as well as loss of excess weight are recommended. \u00a0 Other preventative strategies include ramping up activity or training levels over time rather than engaging in sudden intense exercise.\u00a0 This can help to offset the risk of tearing a meniscus as well as other inducing microtrauma or stress damage to other tissues.\r\n\r\n \r\n\r\nSummary:\r\n\r\n[caption id=\"attachment_1749\" align=\"alignnone\" width=\"300\"]\"Anatomical<\/a> Anatomical Components of the Knee including: quadriceps muscles, quadriceps tendon, femur, patella, patellar tendon (ligament), tibia, fibula, articular cartilage, lateral condyle, posterior cruciate ligament (PCL), anterior cruciate ligament (ACL), lateral collateral ligament, medial collateral ligament, menisci[\/caption]\r\n