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Meniscal tears
Background
Overview
Definition
Meniscal tears are injuries to the meniscus, C-shaped fibrocartilaginous structures acting as cushions between the femoral condyles and tibial plateau. Meniscal tears can be partial or complete and can be caused by trauma (from non-contact sports) or degeneration (such as osteoarthritis).
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Pathophysiology
The pathophysiology of meniscal tears involves disruption of the meniscal tissue, resulting from acute trauma or degeneration. Traumatically torn menisci possess a higher degree of degeneration than intact menisci, suggesting that patients with a traumatic meniscal tear may already have had a certain degree of meniscal degeneration. On a molecular level, traumatic meniscus tears exhibit a higher inflammatory/catabolic response as evidenced by higher levels of chemokine and matrix metalloproteinase expression than degenerative tears.
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Risk factors
Risk factors for meniscal tears include advanced age, sports participation (especially pivoting sports such as basketball, soccer, and football), certain occupations associated with kneeling and squatting, and higher BMI. Traumatic meniscal tears are often associated with concomitant ACL injuries. Knee osteoarthritis is the most important risk factors for degenerative meniscal tears.
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Disease course
The clinical course of meniscal tears often involves symptoms such as knee pain, swelling, and mechanical symptoms such as locking, popping, catching, or buckling. Physical examination often reveals posterior knee pain with deep flexion, knee effusion, joint line tenderness, limited ROM, and signs of trauma. Specific diagnostic tests include McMurray test, Thessaly test, Apley grind test, bounce home test, anterior drawer test, and medial-lateral grind test.
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Prognosis and risk of recurrence
The prognosis of meniscal tears depends on factors such as tear location, size, and chronicity. While many tears can be managed conservatively, larger, unstable tears may require surgical intervention for optimal outcomes. The failure rate of meniscal repair at 5 years is reported to be 22.3-24.3%. Meniscal tears managed conservatively and total meniscectomy are associated with an increased risk of developing arthritic changes on imaging.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of meniscal tears are prepared by our editorial team based on guidelines from the American Academy of Orthopaedic Surgeons (AAOS 2024,2023,2022), the American College of Radiology (ACR 2020,2018), the American Academy of Family Physicians (AAFP 2018), the American Physical Therapy Association (APTA 2018), and the British Medical Journal (BMJ 2017).
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Diagnostic investigations
Physical examination: as per AAOS 2024 guidelines, perform a physical examination, including assessment for joint line tenderness, the McMurray test, and the Thesally test, for the diagnosis of acute meniscal tears.
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Diagnostic imaging
Nonpharmacologic interventions
Therapeutic procedures
Surgical interventions
Indications for surgery: as per AAOS 2024 guidelines, consider performing surgical intervention within 6 months of injury in patients with an acute meniscal tear failed conservative treatment.
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Technical considerations for surgery
Specific circumstances
Patients with concomitant ACL injury: as per AAOS 2022 guidelines, consider offering a meniscal-preserving strategy to optimize joint health and function in patients with ACL tear and meniscal tear.
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Patients with knee osteoarthritis
Patients with chronic knee pain