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Meniscus Tears

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(Redirected from Medial Meniscus Tear)

Other Names

  • Medial meniscus tear
  • Lateral meniscus tear
  • Meniscus tear
  • Meniscus repair
  • Bucket handle meniscus tear
  • Meniscus root tear

Background

  • This page refers to injuries to both the Medial Meniscus and Lateral Meniscus
    • Acute tears are covered on this page
    • Chronic overuse or degenerative tears are also covered

History

  • Initially believed to be a functionless, vestigial remains of a leg muscle[1]

Epidemiology

  • Overall, most common injury of the knee
  • Incidence
    • Annual incidence of meniscal injury is about 61 per 100 000 population[2]
    • Likely significantly underestimated
  • Medial affected more commonly than lateral by a ratio of roughly 2:1[3]
  • Meniscus surgery
    • One of the most common orthopedic operations performed
    • 17 per 100,000 in the US up to 154 per 100,000 in South Korea[4]
    • Arthroscopic meniscus repairs in the US doubled between 2005 and 2011.[5]
  • Pediatrics
    • Prevalence unknown, though to be rising with increased sports participation
  • Discoid Meniscus
    • Thought to occur in 3% to 6% of the US population (need citation)
    • True incidence unknown due to some individuals being asymptomatic

Introduction

Pathophysiology of meniscus tears[6]
Meniscal anatomy and relationship to important structures of the knee joint[7]
Schematic drawing of the blood supply of the meniscus demonstrating the different vascular zones (RR is red, RW is red-white, WW is white)[8]
Illustration of the Watanabe classification of discoid meniscus. 1 (complete type), 2 (incomplete type), 3 (Wrisberg type)[9]

General

  • Medial meniscus
    • More common than lateral
    • Posterior horn in degenerative tears
  • Lateral meniscus
    • Commonly seen with ACL injuries

Etiology

  • Acute
    • Usual mechanism of injury is a pivot-shift or rotational injury during athletic activity
    • Most often due to a twisting motion on the partially flexed, weight-bearing knee
    • May also occur as part of more major, combined injuries to the knee
  • Chronic
    • Degenerative process in older individuals

Associated Injuries

Anatomy of the Menisci

  • Medial Meniscus & Lateral Meniscus
    • Crescent-shaped wedges of fibrocartilage oriented circumferentially
    • Positioned between the tibia and the femur in the medial and lateral compartments
  • Function
    • Load transmission
    • Shock absorption
    • Stability
    • Congruence
    • Lubrication
    • Proprioception
  • Discoid Meniscus
    • Congenital variant with abnormal morphology
    • Can create instability of the lateral meniscus
    • Thicker, poor tissue quality and more prone to tears

Risk Factors

Differential Diagnosis

Differential Diagnosis Knee Pain

Clinical Features

History

  • In acute setting, may have description of sudden twisting or turning motion
  • Degenerative or subacute injuries often have no clear mechanism
  • Pain location is usually on the affected side of the joint
  • Often also endorse swelling, clicking, giving way
  • Swelling may wax and wane
  • In bucket handle tears, locking or getting stuck can occur
  • Pain waking patients up from sleeping is common
  • Inability to fully extend the knee

Physical Exam: Physical Exam Knee

  • Effusion may or may not be present, typically seen in acute injuries
  • Gait is often antalgic
  • Joint line tenderness is sensitive but not specific

Special Tests

  • McMurrays Test: Passively flex and extend knee in medial and lateral rotation
  • Apley Grind Test: Prone, affected knee flexed to 90°, medial and lateral rotation with compression
  • Thessaly Test: Standing, knee bent 20-30°, rotate knee medial and laterally
  • Bounce Home Test: Flex knee then passively bring back into extension
  • Joint Line Tenderness: Tenderness along joint line considered most sensitive exam finding (need citation)
    • Squat Test: Perform full squat with legs externally rotated, then repeat with legs internally rotated

Evaluation

Medial meniscus tear seen in coronal and sagittal planes (click to enlarge)[12]
Large horizontal meniscal tear of the posterior horn of the medial meniscus, reaching the tibial surface.[13]

Radiographs

  • Standard Radiographs Knee
  • Acute
    • Often normal
    • Effusion may be seen on lateral view
  • Potential acute findings[14]
    • Squaring of the lateral femoral condyle
    • Cupping of the lateral tibial plateau
    • Widening of the lateral joint space
    • Hypoplastic lateral tibial spine
  • Chronic
    • Joint space narrowing
    • Calcifications may be seen (e.g. CPPD)

MRI

  • General
    • Useful to classify location, direction and type of tear
    • Increased signal within the meniscus
  • Bucket handle tear
    • Flipped meniscus
    • Double PCL or double anterior horn sign
  • Parameniscal Cyst
    • Suggests meniscus tear
  • Discoid Meniscus findings
    • Anterior-posterior diffusely hypertrophic type (slab)
    • Anterior hypertrophy type
    • Posterior hypertrophy type
  • Diagnostic accuracy (need citation)
    • Sensitivity: 93%
    • Specificity: 88%
    • High false positive rate

CT

  • Not typically required
  • May be useful for evaluating associated osseous injuries

Arthroscopy

  • Gold standard[15]
    • Not routinely performed unless unable to obtain an MRI

Classification

Classification of meniscal tear types

Descriptive Classification

  • Location
    • Red zone (outer 1/3, vascularized)
    • Red/white zone (middle 1/3)
    • White zone (inner 1/3, avascular)
  • Position
    • Anterior
    • Middle
    • Posterior third
    • Root
  • Size
    • Small < 5 mm
    • Large > 5 mm
  • Pattern[16]
    • Vertical/longitudinal: common, associated with ACL tear
    • Bucket handle: vertical, fragment may displace into the notch
    • Oblique/flap/parrot beak: may cause mechanical locking symptoms
    • Radial
    • Horizontal: older population, associated with meniscal cyst
    • Complex
    • Root: functionally equivalent to a total meniscectomy
      • Lateral root tears associated with ACL tears
      • Medial root tears associated with chondral injuries

Management

Nonoperative

  • Indications
    • Chronic degenerative changes in elderly patients
    • Patients who are not good surgical candidates
    • Peripheral meniscus tear in red/red zone (peripheral 25-30%)[17]
    • Tears < 5 mm
    • Asymptomatic tears which are thought to be incidental
  • Rest
  • NSAIDS
  • Physical Therapy
  • Corticosteroid Injection

Operative

  • Indications
    • Young, active individuals
    • Centrally located tears
    • Large tears
  • Surgical options
    • Arthroscopic partial meniscectomy (APM)
    • Arthroscopic Meniscus repair
      • Goals: achieve meniscal healing, avoid adverse effects of partial and total meniscectomy
    • Meniscal allograft or transplant
    • Meniscal scaffolds
    • Partial meniscal substitute
      • Designed to re-establish load distribution across the knee joint, providing chondroprotection

Rehab and Return to Play

Rehab Program PDFs

Rehabilitation

  • Early postoperative period
    • Critical to protect compression across repair site to maintain healing
    • Two factors predict compression at the repair site
    • Strength and security of the fixation at the time of surgery
    • Weight bearing status postoperatively
      • Weight bearing status determined by surgeon and patient compliance
  • Weight bearing
    • Critical to help maintain compression across repair site and promote healing
    • Stable: helps reduce and compress vertical longitudinal and bucket-handle tears, may improve healing[18]
    • Unstable: Causes displacement and distraction of radial, root, and complex tears
  • Axial alignemnt
    • Patients with varus deformity at higher risk of atraumatic medial meniscus tears[19]
  • Range of Motion
    • Immobilization following meniscal repair is detrimental to meniscal healing[20]
    • Protected early ROM: important for healing, reduce risk of postop arthrofibrosis
    • Also important to avoid deep flexion which can provide excessive tibiofemoral contact in cadaveric studies
    • Restriction or rate of progression partially depends on stability of tear pattern[21]
    • Early gravity assisted ROM and/or use of continuous passive motion (CPM) device are safe, beneficial in early postop period[22]
    • Progression to loaded deep-flexion activities should be avoided for approximately 3 months until meniscus healing is well underway
  • Blood Flow Restriction Therapy (BFRT)
    • Scant data for meniscus BFRT following meniscus repair, encouraging studies for ACL reconstruction
    • Meta-analysis: rehab using BFRT increased strength, muscle hypertrophy compared to rehabilitation without BFRT[23]

4 Phase Rehabilitation Protocol

  • Proposed by Sherman et al[24]
  • Phase 1 (immediate postoperative)
    • Frequency: Begin 10-14 days postop, 2-3 days/week
    • Goals: healing, reduce pain and swelling, restore extension, restore quadriceps
  • Phase 2 (intermediate phase)
    • Frequency: 1-3 days/week
    • Goals: restore ROM, restore normal weight bearing kinematics, normal balance, normal gait, return to light work or duty, return to recreational sports
  • Phase 3 (minimal protection phase)
    • Frequency: 1-3 days/week
    • Goals: restore stability during single limb activities, restore proprioception, normal running gait, return to work and heavy labor, return to competitive cycling, recreational sports
  • Phase 4 (return to activity, high impact)
    • Frequency: 1-2 days/week
    • Goals: Progress through running and agility program, normal double- and single-leg landing control, return to recreational contact sports, return to competitive or elite sports

Tear Specific Rehab

  • Lind et al tear specific rehab[25]
    • Randomized 60 patients with peripheral, vertical unstable lesions to accelerated or conservative post-operative plan
    • Accelerated: 2 weeks of 0°-90° ROM without a brace, touch weight bearing followed by unrestricted weight bearing and ROM
    • They returned to running at 8 weeks, contact sports at 4 months
    • Compared to conservative group, no differences in functional or subjective outcomes at 1 or 2 years
  • Kocabey et al tear specific rehab[26]
    • 55 patients undergoing T-fix repair stratified by tear size
    • Tear <3 cm, longitudinal: full weight bearing postop, ROM was restricted to 0°-90° for 3 weeks and 0°-125° from 3 to 6 weeks
    • Tear >3 cm, longitudinal: immobilized in a knee brace for 3 weeks, allowed weight bearing, ROM advance from 0°-90° (3-6 weeks), 0°-125° (4-8 weeks)
    • Complex, radial tears: Non-weight bearing and no flexion >90° for 6 weeks
    • Return to sport: longitudinal tears at 3 months, complex and radial tears at 4-5 months
    • Outcomes: 96% (meniscus only), 100% (meniscus + ACL recon) showed excellent outcomes

Return to Play/Work

  • General
    • There are no well-established guidelines in the meniscal repair literature guiding return to play[27]
    • Most recommendations are from ACL literature
    • Progression from individual to noncontact to contact drills, team practice, full game play
  • Time to return to play
    • Highly variable based on patient- and sport-specific factors
    • Stable tears may be able to return to sport as early as 3-4 months
    • Complex tears in high risk sports may require 6-8 months
  • Functional evaluation from Sherman et al[24]
    • Subjective
      • Single assessment numeric evaluation (SANE) score
      • Baseline visual analog scale (VAS)
      • ACL Return to Sport after Injury Scale Questionnaire
    • Objective
      • Range of motion full compared to other side
      • No effusion
      • Less than 1 cm difference in quadriceps circumference
      • Biodex strength testing
      • Single leg step down on 20 cm step for 3 reps
      • Y balance test
      • Kinetic drop jump test
      • Single leg hop

Prognosis and Complications

Prognosis

  • Historically, in 1970s, meniscectomy was the gold standard
    • Associated with increased risk of joint space narrowing, degenerative joint disease and osteoarthritis
    • Modern management is centered around preservation, repair, and reconstruction of the meniscus
  • Factors which help determine management
    • Age (old vs young)
    • Activity level
    • Comorbidities
    • Degree of symptoms
    • Physical exam
    • Likelihood meniscus is cause of pain
    • Type and location of tear
  • Arthroscopic partial meniscectomy (APM)
    • Sihvonen et al: No better than sham arthroscopy[28]
  • Arthroscopic meniscus repair
    • Lee et al: 90.6% success rate for repair at 2.3 years, 71.4% at 6.6 years[29]
    • Nepple et al systematic review: at 5 years, failure rates ranged from 22.3% to 24.3%[30]
  • Meniscus Repair[24]
    • Among 6 studies looking at return to sport among isolated meniscus repair
    • Time to return ranged from 4.3 months to 6.7 months
    • 81 to 100% were able to return to sport
  • Meniscal allografting
    • Bin et al: 10-year follow-up survival was roughly 89.2%[31]

Complications

  • Chronic Pain
  • Knee Osteoarthritis
    • In part, driven by altered knee kinematics and increased peak contract stresses[32]
  • Inability to return to sport
  • Re-injury

See Also

Internal

External

References

  1. ↑ Sutton B: Ligaments: their nature and morphology . Bristol Med Chir J (1883). 1897, 15:344.
  2. ↑ Chambers HG, Chambers RC: The natural history of meniscus tears . J Pediatr Orthop. 2019, 39:53-5.
  3. ↑ Campbell SE, Sanders TG, Morrison WB. MR imaging of meniscal cysts: incidence, location, and clinical significance. Am J Roentgenol 2001;177(2):409-413.
  4. ↑ Park JW: Higher meniscus surgery incidence in Korea compared to Japan or the USA . J Korean Med Sci. 2019, 34:233.
  5. ↑ Abrams GD, Frank RM, Gupta AK, et al. Trends in meniscus repair and meniscectomy in the United States, 2005-2011. Am J Sports Med 2013;41(10):2333–9.
  6. ↑ Duong, Vicky, et al. "Evaluation and treatment of knee pain: a review." Jama 330.16 (2023): 1568-1580.
  7. ↑ Torres, Stephen J., Jason E. Hsu, and Robert L. Mauck. "Meniscal anatomy." Meniscal Injuries: Management and Surgical Techniques (2014): 1-7.
  8. ↑ van Schie, Peter, et al. "Intra-operative assessment of the vascularisation of a cross section of the meniscus using near-infrared fluorescence imaging." Knee Surgery, Sports Traumatology, Arthroscopy (2021): 1-10.
  9. ↑ Hirschmann, M. T., and N. F. Friederich. "Classification: discoid meniscus, traumatic lesions." The Meniscus (2010): 241-246.
  10. ↑ Jarraya M, Roemer FW, Englund M, et al.: Meniscus morphology: does tear type matter? A narrative review with focus on relevance for osteoarthritis research. Semin Arthritis Rheum. 2017, 46:552-61.
  11. ↑ Englund M, Guermazi A, Lohmander SL: The role of the meniscus in knee osteoarthritis: a cause or consequence?. Radiol Clin North Am. 2009, 47:703-12.
  12. ↑ Image courtesy of radiologymasterclass.co.uk, "MRI Knee - Coronal and Sagittal PDFS - Meniscus tear"
  13. ↑ Case courtesy of Frank Gaillard, Radiopaedia.org, rID: 6361
  14. ↑ Kocher, Mininder S., Catherine A. Logan, and Dennis E. Kramer. "Discoid lateral meniscus in children: diagnosis, management, and outcomes." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 25.11 (2017): 736-743.
  15. ↑ Esparragoza-Montero R, Rodriguez-Diaz J, Lanier- Dominguez J, et al. Evaluation of meniscal morphology and relation between the diagnostic findings of magnetic resonance imaging and arthroscopy in lesions of the knee. Invest Clin 2009;50(1): 35-44.
  16. ↑ https://www.orthobullets.com/knee-and-sports/3005/meniscal-injury
  17. ↑ Giuliani JR, Burns TC, Svoboda SJ, Cameron KL, Owens BD: Treatment of meniscal injuries in young athletes. J Knee Surg. 2011, 24:93-100.
  18. ↑ Barber FA. Accelerated rehabilitation for meniscus repairs. Arthroscopy 1994; 10(2):206–10.
  19. ↑ Habata T, Ishimura M, Ohgushi H, et al. Axial alignment of the lower limb in patients with isolated meniscal tear. J Orthop Sci 1998;3(2):85–9.
  20. ↑ de Albornoz PM, Forriol F. The meniscal healing process. Muscles Ligaments Tendons J 2012;2(1):10–8.
  21. ↑ Marchetti DC, Phelps BM, Dahl KD, et al. A contact pressure analysis comparing an all-inside and inside-out surgical repair technique for bucket-handle medial meniscus tears. Arthroscopy 2017;33(10):1840–8.
  22. ↑ Howard JS, Mattacola CG, Romine SE, et al. Continuous passive motion, early weight bearing, and active motion following knee articular cartilage repair: evidence for clinical practice. Cartilage 2010;1(4):276–86.
  23. ↑ Loenneke JP, Wilson JM, Marin PJ, et al. Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol 2012;112(5):1849–59.
  24. ↑ 24.0 24.1 24.2 Sherman, Seth L., et al. "Meniscus injuries: a review of rehabilitation and return to play." Clinics in sports medicine 39.1 (2020): 165-183.
  25. ↑ Lind M, Nielsen T, Fauno P, et al. Free rehabilitation is safe after isolated meniscus repair: a prospective randomized trial comparing free with restricted rehabilitation regimens. Am J Sports Med 2013;41(12):2753–8.
  26. ↑ Kocabey Y, Nyland J, Isbell WM, et al. Patient outcomes following T-Fix meniscal repair and a modifiable, progressive rehabilitation program, a retrospective study. Arch Orthop Trauma Surg 2004;124(9):592–6.
  27. ↑ Willinger L, Herbst E, Diermeier T, et al. High short-term return to sports rate despite an ongoing healing process after acute meniscus repair in young athletes. Knee Surg Sports Traumatol Arthrosc 2019;27(1):215–22.
  28. ↑ Sihvonen R, Paavola M, Malmivaara A, et al.: Arthroscopic partial meniscectomy versus placebo surgery for a degenerative meniscus tear: a 2-year follow-up of the randomised controlled trial. Ann Rheum Dis. 2018, 77:188-95.
  29. ↑ Lee GP, Diduch DR: Deteriorating outcomes after meniscal repair using the Meniscus Arrow in knees undergoing concurrent anterior cruciate ligament reconstruction: increased failure rate with long-term follow-up. Am J Sports Med. 2005, 33:1138-41.
  30. ↑ Nepple JJ, Dunn WR, Wright RW: Meniscal repair outcomes at greater than five years: a systematic literature review and meta-analysis. J Bone Joint Surg Am. 2012, 19:2222-7.
  31. ↑ Bin SI, Nha KW, Cheong JY, Shin YS: Midterm and long-term results of medial versus lateral meniscal allograft transplantation: a meta-analysis. Am J Sports Med. 2018, 46:1243-50.
  32. ↑ Kim JG, Lee YS, Bae TS, et al. Tibiofemoral contact mechanics following posterior root of medial meniscus tear, repair, meniscectomy, and allograft transplantation. Knee Surg Sports Traumatol Arthrosc 2013;21(9):2121–5.
Created by:
John Kiel on 7 July 2019 05:43:58
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Last edited:
10 January 2026 15:01:21
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