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Meniscal Injury

  • Author: Sarjoo M Bhagia, MD; Chief Editor: Consuelo T Lorenzo, MD  more...
 
Updated: Feb 11, 2016
 

Background

The physician treating an athlete with a known or suspected meniscal tear needs to understand the structure and function of the meniscus and the factors involved in treating an athlete with nonoperative versus operative treatment.[1] This article presents a program for rehabilitation after meniscal injuries, meniscectomy, and meniscal repair based on current knowledge of knee biomechanics.

Understanding of the importance of the menisci in the biomechanics of the knee has progressed steadily since 1968, when Jackson wrote, "The exact function of that structure (meniscus) is still a matter of some conjecture."[2] At that time, it was common to remove the entire substance if any doubt existed regarding the integrity of the meniscus. Today, it is known that the menisci are not optional or expendable structures; they have an integral role in normal knee joint mechanics. (See images below.)

Magnetic resonance imaging scan showing a normal m Magnetic resonance imaging scan showing a normal meniscus.
Magnetic resonance imaging scan showing a torn med Magnetic resonance imaging scan showing a torn medial meniscus.
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Pathophysiology

Anatomy

The menisci are C-shaped wedges of fibrocartilage located between the tibial plateau and femoral condyles. The menisci contain 70% type I collagen. The larger semilunar medial meniscus is attached more firmly than the loosely fixed, more circular lateral meniscus. The anterior and posterior horns of both menisci are secured to the tibial plateaus. Anteriorly, the transverse ligament connects the 2 menisci; posteriorly, the meniscofemoral ligament helps stabilize the posterior horn of the lateral meniscus to the femoral condyle. The coronary ligaments connect the peripheral meniscal rim loosely to the tibia. Although the lateral collateral ligament (LCL) passes in close proximity, the lateral meniscus has no attachment to this structure.

The joint capsule attaches to the entire periphery of each meniscus but adheres more firmly to the medial meniscus. An interruption in the attachment of the joint capsule to the lateral meniscus, forming the popliteal hiatus, allows the popliteus tendon to pass through to its femoral attachment site. Contraction by the popliteus during knee flexion pulls the lateral meniscus posteriorly, avoiding entrapment within the joint space. The medial meniscus does not have a direct muscular connection. The medial meniscus may shift a few millimeters, while the less stable lateral meniscus may move at least 1 cm.

In 1978, Shrive et al reported that the collagen fibers of the menisci are oriented in a circumferential pattern.[3] When a compressive force is applied in the knee joint, a tensile force is transmitted to the menisci. The femur attempts to spread the menisci anteroposteriorly in extension and mediolaterally in flexion. Shrive et al further studied the effects of a radial cut in the peripheral rim of the menisci during loading. In joints with intact menisci, the force was applied through the menisci and articular cartilage; however, a lesion in the peripheral rim disrupted the normal mechanics of the menisci and allowed it to spread when a load was applied. The load now was distributed directly to the articular cartilage. In light of these findings, it is essential to preserve the peripheral rim during partial meniscectomy to avoid irreversible disruption of the structure's hoop tension capability.

Blood supply

The blood supply to the menisci is limited to their peripheries. The medial and lateral geniculate arteries anastomose into a parameniscal capillary plexus supplying the synovial and capsular tissues of the knee joint. The vascular penetration through this capsular attachment is limited to 10-25% of the peripheral widths of the medial and lateral meniscal rims. In 1990, Renstrom and Johnson reported a 20% decrease in the vascular supply by age 40 years, which may be attributed to weight bearing over time.[4]

The presence of a vascular supply to the menisci is an essential component in the potential for repair. The blood supply must be able to support the inflammatory response normally seen in wound healing. Arnoczky, in 1982, proposed a classification system that categorizes lesions in relation to the meniscal vascular supply.[5]

  • An injury resulting in lesions within the blood-rich periphery is called a red-red tear. Both sides of the tear are in tissue with a functional blood supply, a situation that promotes healing.
  • A tear encompassing the peripheral rim and central portion is called a red-white tear. In this situation, one end of the lesion is in tissue with good blood supply, while the opposite end is in the avascular section.
  • A white-white tear is a lesion located exclusively in the avascular central portion; the prognosis for healing in such a tear is unfavorable.

Repair of lesions in the red zone has yielded good results, according to Stone. Reports describe techniques for manufacturing a vascular access channel from the peripheral vasculature to improve the chance that tissue in the central region will repair itself.

Biomechanics

The menisci follow the motion of the femoral condyle during knee flexion and extension. Shrive et al presented a model of normal meniscal function.[3] During extension, the femoral condyles exert a compressive force displacing the menisci anteroposteriorly. As the knee moves into flexion, the condyles roll backward onto the tibial plateau. The menisci deform mediolaterally, maintaining joint congruity and maximal contact area. As the knee flexes, the femur externally rotates on the tibia, and the medial meniscus is pulled forward. Studies by Shrive, Fukubayashi, Walker, and Kurosawa state that the menisci directly influence the transmission of forces, distribution of load, amount of contact force, and pressure distribution patterns.

Mechanism of injury

Meniscal injuries, particularly sports-related injuries, usually involve damage due to rotational force. A common mechanism of injury is a varus or valgus force directed to a flexed knee. When the foot is planted and the femur is internally rotated, a valgus force applied to a flexed knee may cause a tear of the medial meniscus. A varus force on a flexed knee with the femur externally rotated may lead to a lateral meniscus lesion. According to Ricklin, the medial meniscus is attached more firmly than the relatively mobile lateral meniscus, and this may result in a greater incidence of medial meniscus injury.[6]

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Epidemiology

Frequency

United States

Although the exact incidence and prevalence of meniscal injury are unknown, it is a fairly common sports-related injury among adults. Although less common than in adults, knee meniscal injuries do occur in individuals who are skeletally immature. Meniscal injuries are rare in children younger than 10 years with morphologically normal menisci.[7]

Mortality/Morbidity

Meniscal injuries usually are associated with pain that results in gait deviation and loss of time from work and/or sport.

Race

A correlation of race and meniscal injuries is not known to exist.

Sex

Meniscal injuries are more common in males, which may be a reflection of males being more involved in aggressive sporting and manual activities that predispose to rotational injuries of the knee.

Age

Meniscal injuries are common in young males who are involved in sporting or manual activities. A second peak of incidence is observed in elderly persons older than 55 years; this incidence is secondary to a degenerate meniscus being susceptible to injuries with minor trauma.[8] Meniscal injuries are rare in children younger than 10 years with morphologically normal menisci.[7]

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Contributor Information and Disclosures
Author

Sarjoo M Bhagia, MD Consulting Staff, OrthoCarolina; Voluntary Teaching Faculty, Carolinas Rehabilitation

Sarjoo M Bhagia, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Physiatric Association of Spine, Sports and Occupational Rehabilitation, Association of Academic Physiatrists, North American Spine Society

Disclosure: Nothing to disclose.

Coauthor(s)

Selina Yingqi Xing, MD, MS Staff Physician, Department of Physical Medicine and Rehabilitation, Temple University

Selina Yingqi Xing, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Physiatric Association of Spine, Sports and Occupational Rehabilitation, American Medical Association

Disclosure: Nothing to disclose.

Michael Weinik, DO Associate Chairman, Associate Professor, Physical Medicine and Rehabilitation, Temple University Hospital

Michael Weinik, DO is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Michael T Andary, MD, MS Professor, Residency Program Director, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine

Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, Association of Academic Physiatrists

Disclosure: Received honoraria from Allergan for speaking and teaching.

Chief Editor

Consuelo T Lorenzo, MD Medical Director, Senior Products, Central North Region, Humana, Inc

Consuelo T Lorenzo, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation

Disclosure: Nothing to disclose.

Additional Contributors

Robert E Windsor, MD, FAAPMR, FAAEM, FAAPM President and Director, Georgia Pain Physicians, PC; Clinical Associate Professor, Department of Physical Medicine and Rehabilitation, Emory University School of Medicine

Robert E Windsor, MD, FAAPMR, FAAEM, FAAPM is a member of the following medical societies: American Academy of Pain Medicine, American Academy of Physical Medicine and Rehabilitation, American College of Sports Medicine, American Medical Association, International Association for the Study of Pain, Texas Medical Association

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors wish to thank Kavita Gupta, DO, MEng, Department of Orthopedics, Center of Physical Medicine and Rehabilitation, University of Dentistry and Medicine of New Jersey, for her previous contributions to this article.

References
  1. Mordecai SC, Al-Hadithy N, Ware HE, Gupte CM. Treatment of meniscal tears: An evidence based approach. World J Orthop. 2014 Jul 18. 5 (3):233-41. [Medline]. [Full Text].

  2. Jackson JP. Degenerative changes in the knee after meniscectomy. Br Med J. 1968 Jun 1. 2(5604):525-7. [Medline]. [Full Text].

  3. Shrive NG, O'Connor JJ, Goodfellow JW. Load-bearing in the knee joint. Clin Orthop Relat Res. 1978 Mar-Apr. 279-87. [Medline].

  4. Renstrom P, Johnson RJ. Anatomy and biomechanics of the menisci. Clin Sports Med. 1990 Jul. 9(3):523-38. [Medline].

  5. Arnoczky SP, Warren RF. Microvasculature of the human meniscus. Am J Sports Med. 1982 Mar-Apr. 10(2):90-5. [Medline].

  6. Yeh PC, Starkey C, Lombardo S, Vitti G, Kharrazi FD. Epidemiology of Isolated Meniscal Injury and Its Effect on Performance in Athletes From the National Basketball Association. Am J Sports Med. 2011 Nov 30. [Medline].

  7. Iobst CA, Stanitski CL. Acute knee injuries. Clin Sports Med. 2000 Oct. 19(4):621-35, vi. [Medline].

  8. Goldstein J, Zuckerman JD. Selected orthopedic problems in the elderly. Rheum Dis Clin North Am. 2000 Aug. 26(3):593-616. [Medline].

  9. Stanitski CL, Harvell JC, Fu F. Observations on acute knee hemarthrosis in children and adolescents. J Pediatr Orthop. 1993 Jul-Aug. 13(4):506-10. [Medline].

  10. Yoo JC, Ahn JH, Lee SH, et al. Increasing incidence of medial meniscal tears in nonoperatively treated anterior cruciate ligament insufficiency patients documented by serial magnetic resonance imaging studies. Am J Sports Med. 2009 Apr 9. [Medline].

  11. Konan S, Rayan F, Haddad FS. Do physical diagnostic tests accurately detect meniscal tears?. Knee Surg Sports Traumatol Arthrosc. 2009 Apr 28. [Medline].

  12. Rinonapoli G, Carraro A, Delcogliano A. The clinical diagnosis of meniscal tear is not easy. Reliability of two clinical meniscal tests and magnetic resonance imaging. Int J Immunopathol Pharmacol. 2011 Jan-Mar. 24(1 Suppl 2):39-44. [Medline].

  13. Rytter S, Kirkeskov Jensen L, Bonde JP, et al. Occupational kneeling and meniscal tears: a magnetic resonance imaging study in floor layers. J Rheumatol. 2009 May 1. [Medline].

  14. Wareluk P, Szopinski KT. Value of modern sonography in the assessment of meniscal lesions. Eur J Radiol. 2011 Oct 5. [Medline].

  15. Vance K, Meredick R, Schweitzer ME, et al. Magnetic resonance imaging of the postoperative meniscus. Arthroscopy. 2009 May. 25(5):522-30. [Medline].

  16. El Ghazaly SA, Rahman AA, Yusry AH, Fathalla MM. Arthroscopic partial meniscectomy is superior to physical rehabilitation in the management of symptomatic unstable meniscal tears. Int Orthop. 2015 Apr. 39 (4):769-75. [Medline].

  17. Stensrud S, Risberg MA, Roos EM. Effect of exercise therapy compared with arthroscopic surgery on knee muscle strength and functional performance in middle-aged patients with degenerative meniscus tears: a 3-mo follow-up of a randomized controlled trial. Am J Phys Med Rehabil. 2015 Jun. 94 (6):460-73. [Medline].

  18. Gauffin H, Tagesson S, Meunier A, et al. Knee arthroscopic surgery is beneficial to middle-aged patients with meniscal symptoms: a prospective, randomised, single-blinded study. Osteoarthritis Cartilage. 2014 Jul 30. [Medline].

  19. Englund M, Guermazi A, Roemer FW, et al. Meniscal tear in knees without surgery and the development of radiographic osteoarthritis among middle-aged and elderly persons: The Multicenter Osteoarthritis Study. Arthritis Rheum. 2009 Mar. 60(3):831-9. [Medline].

  20. Church S, Keating JF. Reconstruction of the anterior cruciate ligament: timing of surgery and the incidence of meniscal tears and degenerative change. J Bone Joint Surg Br. 2005 Dec. 87(12):1639-42.

 
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Magnetic resonance imaging scan showing a normal meniscus.
Magnetic resonance imaging scan showing a torn medial meniscus.
Arthroscopic probing of a posterior horn complex meniscal tear with multiple flaps.
Arthroscopic view of medial meniscus after excision of flap tear.
 
 
 
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