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Meniscus Tears
From WikiSM
Contents
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
- 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

Meniscal anatomy and relationship to important structures of the knee joint[6]

Schematic drawing of the blood supply of the meniscus demonstrating the different vascular zones (RR is red, RW is red-white, WW is white)[7]

Illustration of the Watanabe classification of discoid meniscus. 1 (complete type), 2 (incomplete type), 3 (Wrisberg type)[8]
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
- Acute
- Osteochondral Defect
- Multiligament Knee Injury
- ACL Injury
- PCL Injury
- MCL Injury
- LCL Injury
- Posterolateral Corner Injury
- Bone contusion, less commonly fracture
- Chronic
- Knee Osteoarthritis
- Up to 75% of patients with knee OA have a meniscal injury[9]
- Knee Osteoarthritis
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
- Male > Female
- Up to 80% of cases reported in men[10]
- Orthopedic
Differential Diagnosis
Differential Diagnosis Knee Pain
- Fractures
- Dislocations & Subluxations
- Patellar Dislocation (and subluxation)
- Knee Dislocation
- Proximal Tibiofibular Joint Dislocation
- Muscle and Tendon Injuries
- Ligament Pathology
- Arthropathies
- Bursopathies
- Patellofemoral Pain Syndrome (PFPS)/ Anterior Knee Pain)
- Neuropathies
- Other
- Bakers Cyst (Popliteal Cyst)
- Patellar Contusion
- Pediatric Considerations
- Patellar Apophysitis (Sinding-Larsen-Johnansson Disease)
- Patellar Pole Avulsion Fracture
- Tibial Tubercle Avulsion Fracture
- Tibial Tuberosity Apophysitis (Osgood Schalatters Disease)
- Proximal Tibial Metaphyseal Fracture
- Proximal Tibial Physeal Injury
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)[11]

Large horizontal meniscal tear of the posterior horn of the medial meniscus, reaching the tibial surface.[12]
Radiographs
- Standard Radiographs Knee
- Acute
- Often normal
- Effusion may be seen on lateral view
- Potential acute findings[13]
- 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[14]
- Not routinely performed unless unable to obtain an MRI
Classification
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[15]
- 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%)[16]
- 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
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[17]
- 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[18]
- Range of Motion
- Immobilization following meniscal repair is detrimental to meniscal healing[19]
- 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[20]
- Early gravity assisted ROM and/or use of continuous passive motion (CPM) device are safe, beneficial in early postop period[21]
- 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[22]
4 Phase Rehabilitation Protocol
- Proposed by Sherman et al[23]
- 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[24]
- 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[25]
- 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[26]
- 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[23]
- 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
- Subjective
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[27]
- Arthroscopic meniscus repair
- Meniscus Repair[23]
- 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%[30]
Complications
- Chronic Pain
- Knee Osteoarthritis
- In part, driven by altered knee kinematics and increased peak contract stresses[31]
- Inability to return to sport
- Re-injury
See Also
Internal
External
- Sports Medicine Review Knee Pain: https://www.sportsmedreview.com/by-joint/knee/
References
- ↑ Sutton B: Ligaments: their nature and morphology . Bristol Med Chir J (1883). 1897, 15:344.
- ↑ Chambers HG, Chambers RC: The natural history of meniscus tears . J Pediatr Orthop. 2019, 39:53-5.
- ↑ Campbell SE, Sanders TG, Morrison WB. MR imaging of meniscal cysts: incidence, location, and clinical significance. Am J Roentgenol 2001;177(2):409-413.
- ↑ Park JW: Higher meniscus surgery incidence in Korea compared to Japan or the USA . J Korean Med Sci. 2019, 34:233.
- ↑ 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.
- ↑ Torres, Stephen J., Jason E. Hsu, and Robert L. Mauck. "Meniscal anatomy." Meniscal Injuries: Management and Surgical Techniques (2014): 1-7.
- ↑ 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.
- ↑ Hirschmann, M. T., and N. F. Friederich. "Classification: discoid meniscus, traumatic lesions." The Meniscus (2010): 241-246.
- ↑ 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.
- ↑ 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.
- ↑ Image courtesy of radiologymasterclass.co.uk, "MRI Knee - Coronal and Sagittal PDFS - Meniscus tear"
- ↑ Case courtesy of Frank Gaillard, Radiopaedia.org, rID: 6361
- ↑ 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.
- ↑ 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.
- ↑ https://www.orthobullets.com/knee-and-sports/3005/meniscal-injury
- ↑ Giuliani JR, Burns TC, Svoboda SJ, Cameron KL, Owens BD: Treatment of meniscal injuries in young athletes. J Knee Surg. 2011, 24:93-100.
- ↑ Barber FA. Accelerated rehabilitation for meniscus repairs. Arthroscopy 1994; 10(2):206–10.
- ↑ 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.
- ↑ de Albornoz PM, Forriol F. The meniscal healing process. Muscles Ligaments Tendons J 2012;2(1):10–8.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 23.0 23.1 23.2 Sherman, Seth L., et al. "Meniscus injuries: a review of rehabilitation and return to play." Clinics in sports medicine 39.1 (2020): 165-183.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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:
22 March 2023 22:37:24
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