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Common Sports Injuries Meniscus Tears BY NEIL BARRY USI 10098422 By Neil Barry. USI 1009842 • Introduction: based on the mechanism of meniscus tear injuries, common sports these injuries are associated with, and their rehabilitative and medical management options. Anatomy • The Knee Above and Below • The Hip: good structural interity of the knee helps maintain a healthy Q angle at the hip. Poor stability at the kneecan lead toincreased Q angle, causing knee valgus. This can lead to weakness in the abductor group. • The hamstring and quadriceps group can also be affeted by knee dysfunction overtime. • Notably, the vastus medialis oblique (VMO) tends to lose bulk rapidly with decreases in knee Above and Below Meniscus• The word "meniscus" refers to a crescent-shaped structure. The medial meniscus of the knee is a thickened crescentshaped cartilage pad between the two joints formed by the femur (the thigh bone) and the tibia (the shin bone). The meniscus acts as a smooth surface for the joint to move on. • - Head of right tibia seen from above, showing menisci and attachments of ligaments-> Medial Meniscus • The medial meniscus is a C shaped fibrocartilage, the circumference of which is attached firmly to the medial articular facet of the tibia and to tthe joint capsule by the coronary ligaments. Posteriorly, it is also attached to fibers of the semimembrinosus muscle Lateral Meniscus • This is more O shaped • The ligament of Wrisberg and is attached to the is the part of the lateral lateral articular facet on meniscus that projects the superior aspect of the upward, close to the tibia. The lateral meniscus attachment of the posterior also attaches loosely to cruciate ligament. the lateral articular capsule • The transverse ligament and to the popliteal joins the anterior portions tendon. of the lateral and medial mensici. The Meniscus • • • • • • • Anterior and posterior meniscal horns attach to the intercondylar eminence of the tibial plateau. The coronary ligaments provide peripheral attachments between the tibial plateau and the perimeter of both menisci. The medial meniscus is also attached to the medial collateral ligament, which limits its mobility. The lateral meniscus is connected to the femur via the anterior (ligament of Humphrey) and posterior (ligament of Wrisberg) meniscofemoral ligaments, which can tension its posterior horn anteriorly and medially with increasing knee flexion. The transverse ligament provides a connection between the anterior aspects of both menisci. The increased stability provided by the ligamentous attachments prevents the menisci from being extruded out of the joint during compression. The meniscus is typically an avascular structure with the primary blood supply limited to the periphery. Only the peripheral 10% to 25% of the meniscus is vascularized. For that reason, when meniscus is damaged in the central portion it is usually unable to undergo a normal healing process. The most peripheral portion of the meniscus which has a blood supply and is more likely to heal. Meniscal Blood Supply • Blood is supplied to each meniscus by the medial genicular artery. Each meniscus can be divided int three circumferential zones: the red-red zone is the outer, one third and has a good vascular supply; • the red-white zone is the middle one third and has minimal blood supply; • the white-white zone on the Clinical Presentation, Assessment and Diagnosis • Joint line tenderness and effusion, either medially or laterally, however it is of note that because the inner portion of the meniscus is avascular and without nerve supply, an injury to the meniscus can result in no pain or swelling. • Symptoms are frequently worsened by flexing and loading the knee, activities such as squatting and kneeling are poorly tolerated. • Complaints of 'clicking', 'locking' and 'giving way' are common • Joint line tenderness has been reported to be the best common test for meniscal injury. • Arthroscopy and Imaging Meniscal Lesions • The medial meniscus has a much higher incidence of injury than does the lateral because the coronary ligament attaches the medial meniscus peripherally to the tibia and also to the capsular ligament. The lateral meniscus does not attach to the capsular ligament and is more mobile during knee movement. • Because of the attachment to the medial structures, the medial meniscus is prone to disruption from valgus and torsional forces. Special Tests • McMurray's test positive if a pop or a snap at the joint line occurs while flexing and rotating the patient's knee. • Apley's test performed with the patient prone, and with the examiner hyperflexing the knee and rotating the tibial plateau on the condyles. • Steinman's test performed on a supine patient by bringing the knee into flexion and rotating. • Ege's Test is performed with the patient squatting, an audible and palpable click is heard/felt over the area of the meniscus tear. The patient's feet are turned outwards to detect a medial meniscus tear, and turned inwards to detect a lateral meniscus tear. Common Mechanism of Injury in Sports • a valgus force can adduct the knee, often tearing and stretching the medialcollateral ligament; meanwhile its fibers twist the medial meniscus outward. • repeated mild strains reduce the strength of the knee to a favorable one for catilaginous tear through lessoning its noral ligamentous stability. • the most common mechanism is weight bearing with a rotational force while the knee is extended or flexed. • cutting motions made while running can also distort the medial meniscus. Mechanism continued • another way a longitudinal tear can occur is when the knee is forcefully extended from a flexed positionwhile the femur is internally rotated. • during extension the medial meniscus is suddenly pulled back, causing the tear. • The lateral meniscus can sustain an oblique tear, when the knee is forcefully extended while externally rotated. • as a result of the force of this action, the meniscus is pulled out of its normal bed and pinched between the femoral condyles. Evidence Based Guidelines • Symptoms and signs • Dx of these injuries should be made as early as possible, to avoid muscle spasm and swelling obscuring the normal shape of the knee. • A meniscal tear may or may not result in the following: • effusion developing gradually over 48-72 hurs • joint-line pain and loss of motion • intermittent locking and giving way of the knee • pain during a squat Signs cont'd • After meniscal tears the rutured edges harden, and may eventually atrophy. • Portions of the meniscus MAY become detached and wedge between the articulating surfaces of the tibia and femur, thus imposing a locking, catching or giving way of the joint. • Chronic lesions may result in recurrent swelling and atrophy around knee. • The patient may complain of a sense of the knee collapsing, of a popping sensation. • May be an inability to squat or change direction quickly without pain when running. such symtoms may prompt surgical intervention. Treatment Options • Tears in the mid substance of the meniscus often fails to heal because of its inadequate blood supply. • The knee that is locked by a displaced meniscus may require unlocking with the patient under anesthesia so that a detailed examination can be done. • If locking continues, arthroscopic surgery may be required to remove a portion of the meniscus. • Surgery should attempt to save as much of the menisci as possible as it plays a critical role in preventing degenerative joint disease. Rehabilitation • Post surgical management for a partial menisectomy does not require bracing and allows partial to full weight bearing on crutches as quickly as can be tolerated for about 2 weeks, even sooner for the active athletic population in some cases. • A repaired meniscus requires immobilization in a brace for 5-6 weeks. • The patient should be on crutches, progressing from partial to full weigh bearing at 6 weeks. • During immobilization, active ROM exercises btwn 0-90 degrees should be done. • At 6 weeks, full ROM resistive exercises can begin. Rehab should thereafter concentrate on endurance. Prehab for Meniscus Tears • Ensuring the knee joint is both strong and flexible • Address muscle imbalances early • Ensure good functional symmetry of the adductors and abductors • Stretching of the knee musculature • Manage the extensibility of the hamstrings, erector spinae, groin, quadriceps and gastrocnemius. • Injured knees must be properly rehabilitated. References • http://physicaltherapyweb.com/mcmurray-test-orthopedicexamination-knee/ • http://www.pthaven.com/page/show/102042-apleydistraction-and-compression • http://www.physio-pedia.com/Steinman_Test • http://www.physio-pedia.com/Ege's_Test • Prentice, William. Principles of Athletics Training, 11th edit: 591-622. 2003