Acute or degenerative tear of the medial or lateral meniscus causing joint-line pain, effusion, and mechanical symptoms.
Also known as: meniscus tear, meniscal tear, medial meniscus, lateral meniscus
Overview
Tear of the fibrocartilaginous meniscus of the knee. Acute tears typically result from a twisting injury on a planted foot in younger active patients. Degenerative tears occur in middle-aged and older adults often with minimal or no recalled trauma and coexisting OA.
Epidemiology
One of the most common knee injuries. Acute tears peak in athletes 20-40. Degenerative tears prevalent in adults >40, especially with knee OA.
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Question 1MusculoskeletalMedium
A 24-year-old recreational soccer player presents with right knee pain that began 3 days ago when she planted her foot and twisted while changing direction, feeling a pop. Since then she has had medial-sided pain and a sensation of catching. On exam she has a moderate effusion, tenderness along the medial joint line, and a positive McMurray test; the Lachman test is negative. Weight-bearing radiographs of the knee show no fracture, normal alignment, and no joint-space narrowing. Which of the following is the most appropriate next diagnostic test to confirm the suspected diagnosis?
ACT scan of the knee
BKnee ultrasonography
CMRI scan of the knee
DKnee MR arthrography
EArthroscopy of the knee
Reveal answer & full explanation
Correct answer: C — MRI scan of the knee
ACT scan of the knee
BKnee ultrasonography
CMRI scan of the knee✓
DKnee MR arthrography
EArthroscopy of the knee
Why MRI scan of the knee is correct
The twisting mechanism on a planted foot, medial joint-line tenderness, mechanical catching, and a positive McMurray test point to a meniscal tear.
Normal weight-bearing radiographs have already excluded fracture and significant osteoarthritis but cannot image the fibrocartilaginous meniscus.
MRI is the noninvasive gold standard for confirming a meniscal tear and characterizing its morphology (radial, longitudinal, bucket-handle, root) with high sensitivity and specificity, which is why it is the appropriate next study after plain films.
Why the others are wrong
CT scan of the knee — Excellent for bony detail and occult fractures but has poor soft-tissue contrast; it does not reliably visualize meniscal cartilage and adds radiation without answering the question.
Knee MR arthrography — Intra-articular gadolinium is added to separate recurrent tear from healing granulation tissue in a previously repaired or resected meniscus; in a native knee with a first-time tear it is invasive and adds nothing to conventional MRI.
Knee ultrasonography — Can assess some superficial soft tissues and effusions but is operator-dependent and far less sensitive than MRI for the meniscus, so it is not the confirmatory study of choice.
Arthroscopy of the knee — arthroscopy directly visualizes the meniscus and remains the reference standard against which MRI is judged, but it is invasive and requires anesthesia, and it is generally reserved for treatment once MRI has confirmed and characterized the tear; it is not the next diagnostic test after normal radiographs.
Question 2MusculoskeletalMedium
A 58-year-old man reports 6 weeks of medial right knee pain that began insidiously after gardening. He denies any locking, catching, or giving way, and the knee extends fully. Exam shows medial joint-line tenderness and a small effusion; McMurray reproduces medial joint-line pain. Weight-bearing radiographs show medial joint-space narrowing and small osteophytes. MRI confirms a horizontal degenerative tear of the medial meniscus. Which of the following is the most appropriate initial management?
AArthroscopic repair of the meniscus
BArthroscopic partial meniscectomy
CPhysical therapy and oral NSAIDs
DIntra-articular steroid injection
EOral glucosamine and chondroitin
Reveal answer & full explanation
Correct answer: C — Physical therapy and oral NSAIDs
AArthroscopic repair of the meniscus
BArthroscopic partial meniscectomy
CPhysical therapy and oral NSAIDs✓
DIntra-articular steroid injection
EOral glucosamine and chondroitin
Why Physical therapy and oral NSAIDs is correct
This is a degenerative horizontal meniscal tear in a 58-year-old with coexisting early osteoarthritis (joint-space narrowing, osteophytes) and NO mechanical symptoms (no locking, catching, or block to extension). Guideline-concordant initial management is conservative: physical therapy (quadriceps/core strengthening, range of motion) plus NSAIDs and activity modification. Multiple high-quality trials (MeTeOR, ESCAPE) show arthroscopy is not superior to PT for degenerative tears with OA.
Why the others are wrong
Arthroscopic partial meniscectomy: not superior to physical therapy or sham for degenerative tears with OA, and it can accelerate cartilage loss; it is not first-line here.
Arthroscopic repair of the meniscus: reserved for peripheral, vascular (red-red zone) tears in younger patients; a degenerative horizontal tear in an older adult is not repairable.
Intra-articular steroid injection: a reasonable adjunct for OA-related pain, but it is not the appropriate initial step over physical therapy and NSAIDs.
Oral glucosamine and chondroitin — supplements marketed for cartilage health appeal to a patient with early osteoarthritis, but high-quality trials show no meaningful benefit over placebo and ACR guidelines recommend against them; they do nothing for the meniscal tear and are no substitute for physical therapy and NSAIDs.
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The menisci distribute load and stabilize the knee. A twisting force on the flexed and loaded knee — or repetitive degenerative wear — produces a tear. The peripheral 'red-red' zone (outer 1/3) is vascularized and may heal; the inner 'white-white' zone is avascular and does not heal. Tear morphology (radial, horizontal, longitudinal, complex, bucket-handle, root tear) influences treatment.
Clinical presentation
Symptoms
Acute tear: twisting injury, often with a popping sensation, followed by pain along the joint line
Effusion developing over 12-24 hours (slower than ACL effusion)
Mechanical symptoms: catching, locking, giving way
Degenerative tear: insidious medial joint-line pain, may follow squatting or rising from chair, often with coexisting OA symptoms
Signs / physical exam
Joint-line tenderness (medial > lateral) — best clinical sign
Effusion
Positive McMurray test (joint line pain or click with flexion and rotation)
Positive Thessaly test (pain with internal/external rotation while standing on the affected leg)
Positive Apley grind test (prone, knee flexed 90 degrees, axial compression plus tibial rotation reproduces joint-line pain); pain with deep squatting
Reduced flexion or true mechanical block to extension (consider bucket-handle tear)
Differential diagnosis
ACL tear — Audible pop, immediate large effusion, instability; positive Lachman; often coexists with meniscus tear (especially lateral)
Medial collateral ligament (MCL) sprain — Valgus mechanism; tenderness along medial joint line above and below; pain with valgus stress
Patellofemoral pain syndrome — Anterior knee pain with stairs, prolonged sitting; no joint-line tenderness or mechanical symptoms
Osteoarthritis — Insidious onset, X-ray findings, often coexists with degenerative meniscal tears
Osteochondral lesion — Catching/locking, X-ray or MRI changes
Pes anserine bursitis — Tender ~5 cm distal to the medial joint line at the pes anserine insertion
Loose body — Episodic locking, joint-line pain, MRI/CT diagnostic
Not indicated unless concern for inflammatory or septic etiology
Imaging
Weight-bearing knee X-rays — evaluate for OA, fracture, alignment
MRI — gold standard for confirming meniscal tear and characterizing morphology; high sensitivity and specificity
Arthroscopy — diagnostic and therapeutic in selected cases
Diagnostic algorithm
Feature
Acute meniscus tear
Degenerative meniscus tear
Typical patient
Athlete 20-40
Adult >40 with OA
Mechanism
Twisting on planted foot
Insidious; minor stress
Effusion
Develops over 12-24 h
Variable, often small
Mechanical symptoms
Common (locking, catching)
Less common
Imaging
MRI confirms tear
MRI commonly shows tear; correlate clinically
First-line treatment
PT, NSAIDs, often arthroscopy
PT, NSAIDs; arthroscopy NOT superior
Surgical indication
Locked knee, repairable tear, refractory symptoms
Rare — only if true mechanical symptoms
Acute vs degenerative meniscus tears — different patients, different treatment thresholds.
Treatment
First-line
Activity modification, avoidance of pivoting and deep squatting
RICE (rest, ice, compression, elevation) acutely
NSAIDs — ibuprofen, naproxen, meloxicam — for pain and effusion
Acetaminophen as adjunct
Physical therapy — quadriceps and core strengthening, range of motion
Intra-articular corticosteroid injection — short-term adjunct for pain in degenerative tears with OA; does not replace initial exercise-based physical therapy
Retear after repair (especially in white-white zone)
Locked knee with unrepaired bucket-handle tear
PANCE pearls
Joint-line tenderness is the single most useful exam finding for meniscal tear.
Knee that cannot fully extend after a twisting injury is concerning for a bucket-handle tear — urgent orthopedic referral.
Arthroscopic partial meniscectomy does not outperform physical therapy (MeTeOR in tears with OA; ESCAPE in nonobstructive tears) or sham surgery (FIDELITY) for degenerative meniscus tears; counsel patients accordingly.
Meniscal repair is preferred over meniscectomy whenever the tear is in the vascular zone and the patient is young — preserves cartilage.
AAOS 2021 — AAOS Clinical Practice Guideline on Management of Osteoarthritis of the Knee (Non-Arthroplasty), 3rd ed. (2021)
MeTeOR Trial — Surgery vs Physical Therapy for a Meniscal Tear and Osteoarthritis (Katz et al., NEJM 2013)
ESCAPE Trial — Effect of Early Surgery vs PT on Knee Function in Patients with Nonobstructive Meniscal Tears (van de Graaf et al., JAMA 2018)
FIDELITY Trial — Arthroscopic Partial Meniscectomy versus Sham Surgery for a Degenerative Meniscal Tear (Sihvonen et al., N Engl J Med 2013;369:2515-2524)
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