Injuries

April 2012

FocusInjuries

Meniscal tear

Presentation, diagnosis and management

Volume 41, No.4, April 2012 Pages 182-187

Tim Shiraev

Suzanne E Anderson

Nigel Hope

Background

Medial and lateral knee joint menisci serve to transfer load and absorb shock, aid joint stability and provide lubrication. The meniscus is the most commonly injured structure in the knee joint. Imaging techniques such as magnetic resonance imaging may be warranted but are no substitute for thorough clinical history and examination.

Objective/s

This article outlines the aetiology, presentation, diagnosis (both clinical and radiographic) and management of these important injuries.

Discussion

Magnetic resonance imaging can confirm clinical concern for meniscal tear, review intra- and extra-articular anatomical structures and exclude alternative diagnoses. Meniscal tears can be assessed arthroscopically for stability and vascularity. Even partial meniscectomy may lead to osteoarthritis. On the basis of the findings, treatment can be considered in terms of four Rs: Rest and Rehabilitate the patient (with physiotherapy), and if the patient is not improving on Review, Refer to an orthopaedic surgeon. New experimental surgical techniques seek to replace damaged tissue. These include meniscal allograft transplantation, biosynthetic scaffolds, growth factor and gene therapy, or a combination of these.

Injury of the knee joint meniscus is one of the most prevalent injuries in the human body. Its investigation and treatment includes surgical techniques that are among the most commonly performed orthopaedic procedures worldwide. The past few decades have seen striking advances in our understanding of meniscal structure, function and the treatment of meniscal injuries. Attitudes toward total meniscectomy have undergone reversal in the past 30 years, and even today, practices are rapidly changing. Early, clinical examination, appropriate investigation and treatment of meniscal injuries may prevent later degenerative disease and inappropriate surgical treatment that can predispose to later degenerative change. This article outlines the aetiology, presentation, diagnosis (both clinical and radiographic) and management of these important injuries.

The menisci of the knee have several important roles:

  • shock absorption and distributing load throughout the joint
  • increasing stability
  • providing nutrition for articular cartilage
  • limiting extreme flexion and extension
  • controlling the movements of the knee joint.1,2

The medial meniscus is 'C' shaped whereas the lateral is a shorter incomplete circle with closer spaced 'horns'. The medial meniscus is more frequently torn, partly because of this different shape but also because of its attachment to the medial collateral ligament, whereas the lateral is pulled out of the way of compression between femur and tibia by politeus. Superior and inferior branches of the medial and lateral geniculate arteries supply the peripheral third of the menisci via the perimeniscal capillary plexus.3,4

Epidemiology, aetiology and pathophysiology

Meniscal tears occur due to a shear force between the femur and tibia. In younger patients, this is typically a twisting force on a weightloaded flexed knee. These are often 'bucket-handle tears', in which there is a vertical or oblique tear in the posterior horn running toward the anterior horn,5 forming a loose section which remains attached anteriorly and posteriorly.1 In older patients, tears are generally due to degeneration associated with ageing and tend to be horizontal tears. The difference in tear type between these populations is explained by the three-dimensional fibrous structure of the meniscus: horizontal delamination occurs in degenerative injuries, while the fibrous structure is ruptured in a vertical fashion in younger patients. Meniscal tear incidence may be as high as six per 1000 population6 with a 2.5 to 4 times male predominance. Age of injury peaks at 20–29 years.7 Partial meniscectomy (removal of the torn section) is one of the most commonly performed orthopaedic surgical procedures.8

History and examination

Meniscal tears often occur in young patients who have suffered a twisting injury to the knee. Tears present as severe pain, swelling, and possibly catching, clicking, difficulty on deep knee bending and locking of the knee in partial flexion.

The typical meniscal pain profile comprises well localised joint-line pain (with medial pain generally being indicative of a medial tear and vice-versa). Meniscal pain occurs during torsional, weight bearing knee movements (classically pivoting on the knee while walking) as a sharp stab lasting several seconds, often followed by a dull ache for several hours. Pain may wake the patient from sleep as the tender medial aspect of the knee strikes the other side as the patient rolls over in bed. There is no resting pain.

Locking presents in two ways. Most commonly it is impossible to fully extend the knee; more accurately described as stiffness (termed 'pseudo locking') due either to a small effusion (requiring increased force to bend the tense joint capsule) or to pain inhibition as the femoral condyle compresses the torn meniscus. True locking is less common, and suggests a bucket-handle tear, with the torn fragment preventing full extension. There is a history of sudden inability to fully extend the knee, with a rotational flexion/extension 'trick' required to regain full extension. Weakness, grinding, instability or giving way rarely result from meniscal pathology.

On examination, there may be joint effusion, joint line tenderness, and the joint is held in a flexed position.1 in late presentations, there may be significant quadriceps wasting. McMurray (Figure 1) and Apley tests (Figure 2) are often positive, although these are specific but not sensitive – specificity being 57–98% and 80–99%, and sensitivity being 10–66% and 16–58% respectively.2,9 The most useful clinical test for meniscal injury is the Thessaly test, which is demonstrated in Figure 3. Although rarely taught and poorly utilised, recent validation demonstrated a sensitivity of 90%, and specificity of 98% in detecting meniscal injury.10

Diagnosis

If clinically suspicious of meniscal injury, a trial of conservative measures may be considered or confirmation with magnetic resonance imaging (MRI). Unfortunately, general practitioners cannot currently order Medicare funded MRI, although this may change with The Royal Australian College of General Practitioners recent submission to the Australian Government Department of Health and Ageing. 11 Plain radiography is only useful to exclude differentials and computed tomography (CT) is markedly inferior to MRI for meniscal imaging.12 Magnetic resonance imaging is the gold standard, first choice for investigation of suspected meniscal tears.2,13–16

Sagittal peripheral meniscal images demonstrate the normal anatomical 'bow-tie configuration' (the central meniscal body with the anterior and posterior horns as well circumscribed triangles. On MRI, meniscal tears are evident as a linear signal intensity that extends through the meniscal substance to a free edge17 (Figure 4). Tears are typically vertical in young patients and horizontal in the elderly (Figure 5). Magnetic resonance imaging can also be effectively used to estimate the vascular zone classification (see Treatment) of tears.18 This is useful for the orthopaedic surgeon to predict meniscal repairability, assisting informed discussion with patients and scheduling appropriate operating theatre time.18 It is essential to remember that just because a tear can be seen on MRI, this does not mandate surgery.

Indications for specialist referral

The absolute indication for specialist referral is the locked knee – loss of joint function necessitates surgical intervention. Referral is also indicated if the diagnosis is uncertain for review and to access MRI. In older patients, referral is appropriate if conservative management fails to improve symptoms. As the risk of osteoarthritis is increased if meniscal structures are not optimally functional,7 it may also be appropriate to refer all young patients for opinion if symptoms do not rapidly improve.

Figure 1. McMurray test: The patient lies supine on 
the bed with the hip and knee both flexed. With the 
foot as close to the hip as possible, the clinician 
holds the knee joint (with fingers along the joint 
line) with one hand, and the other hand rotates the 
tibia internally and externally while extending and 
flexing the knee. If the test is positive (suggesting 
a meniscal tear), the patient will feel pain and the 
clinician will feel and/or hear meniscal movement 
when the meniscus is compressed between the 
tibia and femur
32

Figure 1. McMurray test: The patient lies supine on the bed with the hip and knee both flexed. With the foot as close to the hip as possible, the clinician holds the knee joint (with fingers along the joint line) with one hand, and the other hand rotates the tibia internally and externally while extending and flexing the knee. If the test is positive (suggesting a meniscal tear), the patient will feel pain and the clinician will feel and/or hear meniscal movement when the meniscus is compressed between the tibia and femur 32

Figure 2. Apley test (grinding) test: The patient lies 
prone, with their knee flexed to 90 degrees and their 
hip extended. The clinician applies axial pressure to 
the foot and rotates the tibia internally and externally. Pain and/or clicking on compression suggest 
a meniscal lesion
1,32

Figure 2. Apley test (grinding) test: The patient lies prone, with their knee flexed to 90 degrees and their hip extended. The clinician applies axial pressure to the foot and rotates the tibia internally and externally. Pain and/or clicking on compression suggest a meniscal lesion 1,32

Figure 3. Thessaly test: The clinician holds the 
patient's outstretched hands for support, while the 
patient stands flat-footed with their knee flexed to 
20 degrees and rotates their body and knee three 
times, internally and externally. The test is positive if 
symptoms are reproduced on rotation
10

Figure 3. Thessaly test: The clinician holds the patient's outstretched hands for support, while the patient stands flat-footed with their knee flexed to 20 degrees and rotates their body and knee three times, internally and externally. The test is positive if symptoms are reproduced on rotation 10

Treatment

Nonoperative treatments are an important part of the management of all patients, regardless of whether surgery is being considered. Immediate conservative measures include the RICE regimen:

  • Rest (with weight bearing as tolerated or with crutches)
  • Ice
  • Compression bandaging
  • Elevation of the affected limb to minimise acute swelling and inflammation.

Longer term measures include activity modification, nonsteroidal antiinflammatory drugs (NSAIDs) and physiotherapy.4,19–21 Nonsteroidal anti-inflammatory drugs are often recommended for 8–12 weeks,20 although paracetamol can be considered if NSAIDs are contraindicated or poorly tolerated.22 Where available, intensive physiotherapy is very useful and should include range of motion, proprioceptive work and muscle strengthening exercises. Physiotherapy at two visits per week for at least 8 weeks is recommended.20 There is little evidence for strapping of meniscal injuries and this is not currently recommended.

Nonoperative treatments are often successful in patients with certain types of tear – patients who have no loss of joint function, suffer minimal pain or swelling and are willing to reduce their activities – temporarily or in the long term. A recent study demonstrated 46% of patients with degenerative meniscal tears elected not to have surgery after 4 weeks of nonoperative treatment, and their functional improvement matched patients in the operative group.21 Another study of degenerative tears demonstrated that supervised exercise caused the same reduction in knee pain and the same increase in function and satisfaction as partial meniscectomy plus exercise.23 As degenerative tears are more common in elderly patients, this group is more likely to respond to conservative treatment. The degenerative aetiology and reduced vascularisation secondary to ageing also means that meniscal tears in the elderly population are less likely to be amenable to surgical management;7 only about 6% of patients over 40 years of age have operable lesions.24 To prevent re-injury of the meniscus, activity modification is important – for example, ceasing sports such as soccer or netball. Patients are often aware of movements that aggravate mensical pain, but should also be educated to avoid twisting on a weight bearing, flexed knee.

Surgical treatment is usually reserved for younger patients with a vertical longitudinal tear within the vascularised outer third of the meniscus. This is termed the 'red-red zone' (denoting area of vascularity).2,4 repair of the 'red-white zone' (watershed area between vascular and avascular meniscus) is controversial25 with many different surgical techniques.26 tears in the 'white-white zone' (avascular zone) are rarely repaired – rather the damaged segment is resected (meniscectomy). Damaged avascular meniscus must be removed.27 However, meniscectomy causes long term osteoarthritis,28 so is only performed when the patient suffers joint locking or mensical pain that is refractory to conservative management. For patients requiring meniscectomy, meniscal autograft has been utilised with good outcomes,29–31 but is only performed in specialist centres. Research is currently investigating the possibility of implantation of collagen, allogenic and xenogenic cells, embryonic and adult stem cells, or scaffolds derived from polymers, hydrogels, tissues and extracellular matrix,7 and action of biological stimuli (eg. growth factors) on meniscus tissue is being investigated.2 These are currently only being trialled in younger patients7 and the routine use of most of these technologies is some time away.

Figure 4. Proton weighted sagittal image demonstrates 
an example of a posterior horn medial meniscal horizontal tear (white arrow). The anterior horn of the medial meniscus demonstrates half of the normal anatomic 
'bow-tie configuration'. Note: the cartilage deficit more 
anteriorly on the medial femoral condyle and altered 
subchondral cortical bone interface

Figure 4. Proton weighted sagittal image demonstrates an example of a posterior horn medial meniscal horizontal tear (white arrow). The anterior horn of the medial meniscus demonstrates half of the normal anatomic 'bow-tie configuration'. Note: the cartilage deficit more anteriorly on the medial femoral condyle and altered subchondral cortical bone interface

Figure 5. Coronal proton weighted MRI of horizontal 
tear of lateral meniscus (white arrow) with complicating ganglion (black arrow) at the lateral margin of the 
meniscus

Figure 5. Coronal proton weighted MRI of horizontal tear of lateral meniscus (white arrow) with complicating ganglion (black arrow) at the lateral margin of the meniscus

Key points

  • Meniscal injury is common, and the medial meniscus is more frequently injured.
  • Younger and elderly patients typically sustain different types of tears.
  • Optimal diagnosis and management is essential to prevent long term sequelae.
  • The Thessaly test is the most sensitive and specific clinical test to diagnose meniscal injury.
  • Magnetic resonance imaging is first line for investigating potential meniscal lesions, but should not replace thorough clinical history and examination.
  • Conservative management is important in all patients with acute rest, intensive rehabilitation with physiotherapy and modification of activity. Referral to an orthopaedic surgeon is important if the diagnosis is uncertain or there is minimal improvement at clinical review.

Conflict of interest: none declared.

References

  1. Solomon L, Warwick D, Nayagam S. Apley's Concise System of Orthopaedics and Fractures. 3rd edn. Great Britain: Hodder Arnold, 2005.
  2. Jarit G, Bosco J. Meniscal repair and reconstruction. Bull NYU Hosp Jt Dis 2010;68:84–90.
  3. Arnoczky SP, Warren RF, Spivak JM. Meniscal repair using an exogenous fibrin clot. An experimental study in dogs. J Bone Joint Surg Am 1988;70:1209–17.
  4. Scuderi G, Tria A. The knee: a comprehensive review. Singapore: World scientific, 2010.
  5. Helms CA, Laorr A, Cannon WD, Jr. The absent bow tie sign in bucket-handle tears of the menisci in the knee. AJR Am J Roentgenol 1998;170:57–61.
  6. Metcalf MH, Barrett GR. Prospective evaluation of 1485 meniscal tear patterns in patients with stable knees. Am J Sports Med 2004;32:675–80.
  7. Makris EA, Hadidi P, Athanasiou KA. The knee meniscus: structure-function, pathophysiology, current repair techniques, and prospects for regeneration. Biomaterials 2011;32:7411–31.
  8. Garrett WE Jr, Swiontkowski MF, Weinstein JN, et al. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. J Bone J Surg Am 2006;88:660–7.
  9. Scholten RJ, Deville WL, Opstelten W, Bijl D, van der Plas CG, Bouter LM. The accuracy of physical diagnostic tests for assessing meniscal lesions of the knee: a meta-analysis. J Fam Pract 2001;50:938–44.
  10. Harrison BK, Abell BE, Gibson TW. The Thessaly test for detection of meniscal tears: validation of a new physical examination technique for primary care medicine. Clin J Sport Med 2009;19:9–12.
  11. The Royal Australian College of General Practitioners. Detailed review of funding for diagnostic imaging services. Submission to the Department of Health and Ageing. 2010. Available at www.health.gov.au/internet/ main/publishing.nsf/Content/MBRT-DI-submissions-018/$FILE/018%20 RACGP%20Submission.pdf [Accessed 15 August 2011].
  12. Mui LW, Engelsohn E, Umans H. Comparison of CT and MRI in patients with tibial plateau fracture: can CT findings predict ligament tear or meniscal injury? Skeletal Radiol 2007;36:145–51.
  13. Bernstein J. In brief: meniscal tears. Clin Orthop Related Res 2010;468:1190–2.
  14. Crawford R, Walley G, Bridgman S, Maffulli N. Magnetic resonance imaging versus arthroscopy in the diagnosis of knee pathology, concentrating on meniscal lesions and ACL tears: a systematic review. Br Med Bull 2007;84:5–23.
  15. Liodakis E, Hankemeier S, Jagodzinski M, Meller R, Krettek C, Brand J. The role of preoperative MRI in knee arthroscopy: a retrospective analysis of 2,000 patients. Knee Surg Sports Traumatol Arthrosc 2009;17:1102–6.
  16. Vincken PW, ter Braak AP, van Erkel AR, et al. MR imaging: effectiveness and costs at triage of patients with nonacute knee symptoms. Radiology 2007;242:85–93.
  17. Lufkin R. The MRI manual. 2nd edn. Missouri: Mosby, 1998.
  18. Nourissat G, Beaufils P, Charrois O, et al. Magnetic resonance imaging as a tool to predict reparability of longitudinal full-thickness meniscus lesions. Knee Surg Sports Traumatol Arthrosc 2008;16:482–6.
  19. De Carlo M, Armstrong B. Rehabilitation of the knee following sports injury. Clin Sports Med 2010;29:81–106.
  20. Lim HC, Bae JH, Wang JH, Seok CW, Kim MK. Non-operative treatment of degenerative posterior root tear of the medial meniscus. Knee Surg Sports Traumatol Arthrosc 2010;18:535–9.
  21. Rimington T, Mallik K, Evans D, Mroczek K, Reider B. A prospective study of the nonoperative treatment of degenerative meniscus tears. Orthopedics 2009;32:8.
  22. Bove SE, Flatters SJ, Inglis JJ, Mantyh PW. New advances in musculoskeletal pain. Brain Res Rev 2009;60:187–201.
  23. Herrlin S, Hallander M, Wange P, Weidenhielm L, Werner S. Arthroscopic or conservative treatment of degenerative medial meniscal tears: a prospective randomised trial. Knee Surg Sports Traumatol Arthrosc 2007;15:393–401.
  24. Barrett GR, Field MH, Treacy SH, Ruff CG. Clinical results of meniscus repair in patients 40 years and older. Arthroscopy 1998;14:824–9.
  25. Krych AJ, McIntosh AL, Voll AE, Stuart MJ, Dahm DL. Arthroscopic repair of isolated meniscal tears in patients 18 years and younger. Am J Sports Med 2008;36:1283–9.
  26. Henning C, Lynch M, Clark J. Vascularity for healing of meniscus repairs. Arthroscopy 2010;26:1368–9.
  27. Gillquist J, Hamberg P, Lysholm J. Endoscopic partial and total meniscectomy. A comparative study with a short term follow up. Acta Orthop Scand 1982;53:975–9.
  28. P
  29. apalia R, Del Buono A, Osti L, Denaro V, Maffulli N. Meniscectomy as a risk factor for knee osteoarthritis: a systematic review. Br Med Bull 2011;2011:89–106.
  30. Cole BJ, Dennis MG, Lee SJ, et al. Prospective evaluation of allograft meniscus transplantation: a minimum 2-year follow-up. Am J Sports Med 2006;34:919–27.
  31. Sekiya JK, West RV, Groff YJ, Irrgang JJ, Fu FH, Harner CD. Clinical outcomes following isolated lateral meniscal allograft transplantation. Arthroscopy 2006;22:771–80.
  32. Verdonk PC, Demurie A, Almqvist KF, Veys EM, Verbruggen G, Verdonk R. Transplantation of viable meniscal allograft. Survivorship analysis and clinical outcome of one hundred cases. J Bone Joint Surg Am 2005;87:715–24.
  33. Ercin E, Kaya I, Sungur I, Demirbas E, Ugras AA, Cetinus EM. History, clinical findings, magnetic resonance imaging, and arthroscopic correlation in meniscal lesions. Knee Surg Sports Traumatol Arthrosc 2011 Aug 11. [Epub ahead of print].

Correspondence afp@racgp.org.au

Yes     No

Declaration of competing interests *

Yes No

Additional Author (remove)

Yes No

    

 

 

 

 

Competing Interests: 

Your comment is being submitted, please wait

 

Download citation in RIS format (EndNote, Zotero, RefMan, RefWorks)

Download citation in BIBTEX format (RefMan)

Download citation in REFER format (EndNote, Zotero, RefMan, RefWorks)

For more information see Wikipedia: Comparison of reference management software