The menisci of the human knee arefibrocartilaginous, crescent-shapedstructures that lie on the articularsurface of the tibia (Figure 1). Theyare integral components of knee bio-

mechanics. Injuries to the knee menisci are com-mon, especially among athletes. Short-termsequelae of meniscal injury include knee pain anddeficits in knee range of motion. Long-termsequelae may include degenerative changes in theknee joint with associated pain and stiffness. This

article addresses the anatomy and function of thenormal and injured meniscus, clinical diagnosis ofmeniscal tears, radiographic evaluation, and non-operative as well as surgical treatment options.

MENISCAL ANATOMY AND FUNCTION

The knee menisci are wedge-shaped in crosssection, thicker near the periphery of the jointspace. The menisci are composed largely of type 1collagen fibers arranged primarily in a circumfer-ential orientation (resisting stress along the length

Meniscal Injuries in Active PatientsTheodore T. Manson, MD, MS; Andrew J. Cosgarea, MD

Dr Manson is a resident in the Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, andDr Cosgarea is Associate Professor and Director, Division of Sports Medicine and Shoulder Surgery, Department ofOrthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Md.Conflict of Interest: Drs Manson and Cosgarea report having no financial or advisory relationships with corporate orga-nizations related to this activity.Off-Label Product Discussion: The authors of this article do not include information on off-label use of products.Correspondence to: Andrew J. Cosgarea, MD, Associate Professor and Director, Division of Sports Medicine and ShoulderSurgery, Johns Hopkins University, Department of Orthopaedic Surgery, 10753 Falls Rd, Suite 215, Lutherville, MD 21093.

PURPOSE: Knee injuries are frequent in active individuals. Primary care physicians are oftenconfronted with patients who have sustained tears of the knee menisci. Following a discussionof epidemiology and clinical and radiographic diagnosis of meniscal tears, guidelines forreferral as well as principles of conservative and surgical treatment will be reviewed.

EPIDEMIOLOGY: The overall incidence of meniscal tears that lead to surgery is 60 to 70per 100 000 per year. One third of meniscal tears are associated with sports injuries.

REVIEW SUMMARY: The menisci of the human knee are crescent-shaped structures com-posed of fibrocartilage that lie on the articular surface of the tibia and are integral com-ponents of knee biomechanics. Injuries to the knee menisci are common, especially inathletes. Short-term sequelae of meniscal injury include knee pain as well as deficits inknee range of motion. Long-term sequelae of meniscal injury include degenerativechanges in the knee joint with associated knee pain and stiffness.

Conservative treatments involving nonsteroidal anti-inflammatory drugs (NSAIDs) andphysical therapy are often sufficient for the treatment of meniscal tears. A patient who pre-sents with either mechanical symptoms of catching and locking, or range-of-motiondeficits will often benefit from surgery. Surgical treatment options include partial menis-cectomy or meniscal repair.

TYPE OF AVAILABLE EVIDENCE: Prospective and retrospective cohort studies, case-control series.GRADE OF AVAILABLE EVIDENCE: Fair to Good.CONCLUSION: Meniscal injuries are common and can be diagnosed with a combination

of physical examination and magnetic resonance imaging. Treatment options vary by theage of the patient and extent of torn meniscus, but include physical therapy and NSAIDsfor minimally symptomatic tears and surgery for symptomatic tears or tears that causeabnormalities of joint motion and catching and locking in that range of motion.(Adv Stud Med. 2004;4(10):545-552)

ABSTRACT

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of the meniscus) with some radially oriented fibers(resisting stresses across the cross section of themeniscus).1

The menisci derive their blood supply from a peri-meniscal capillary plexus formed by branches of thesuperior and inferior geniculate arteries. This capillaryplexus penetrates only the outer 10% to 30% of themeniscal tissue.2 The remainder of the inner meniscus isavascular, and its nutritional needs are supplied mainlyby diffusion.3 The clinical significance of this perfusionscheme is that the inner 70% of the meniscus is much

less likely to heal from injury than the periphery and mayneed to be debrided rather than repaired.4

MEDIAL MENISCUS

The medial meniscus is C-shaped and wrapsaround the periphery of the medial joint space. Theanterior horn of the medial meniscus attaches to thetibia anteromedial to the anterior cruciate ligament(ACL) insertion. The posterior horn of the medialmeniscus attaches directly posterior to the ACL inser-tion.5 The medial meniscus also is anchored to the tibiathroughout its periphery to a portion of the joint cap-sule referred to as the coronary ligament. The midpor-tion of the medial meniscus attaches to the deep fibersof the medial collateral ligament. The medial meniscusis widest at its posterior horn and gradually tapers inwidth as it courses anteriorly.

LATERAL MENISCUS

The lateral meniscus is more semicircular in shape,covers a larger area, and is less firmly attached at itsperiphery than the medial meniscus. The anterior andposterior horns of the lateral meniscus attach close toeach other and lateral to the tibial insertion of theACL. The periphery of the lateral meniscus is onlyloosely attached to the joint capsule.6 Two menis-cofemoral ligaments, the ligaments of Humphries andWrisberg, course from the posterior horn of the lateralmeniscus to the medial femoral condyle adjacent theposterior cruciate ligament.

MENISCAL FUNCTION

The knee menisci play a key role in protecting thearticular cartilage from high contact stresses. Themenisci accommodate the shape mismatch betweenthe round femoral condyles and the relatively flat tib-ial articular surface, increasing the contact surface areaof the tibial plateau and thereby decreasing the contactstress at any 1 point. A tear or meniscectomy involving15% to 34% of the meniscus causes an increase in con-tact pressures in the knee joint of up to 350%.7

The viscoelastic menisci also play a role in shockabsorption, with total meniscus removal decreasing theshock absorption capacity of the knee by 20%.8

The conforming natures of the menisci are thoughtto aid in joint proprioception and lubrication as well asto enhance joint stability. In fact, in an ACL-deficientknee, the medial meniscus is the key restraint againstan anterior load applied to the tibia.9,10

MENISCAL INJURY

EPIDEMIOLOGY

The overall incidence of meniscal tears that lead tosurgery is 60 to 70 incidents per 100 000 people peryear.11-13 One third of meniscal tears are associated with

Figure 1. Anatomy of the Tibial Plateau From Above

Reprinted with permission from Warren R, Arnoczky SP, Wickiewicz TL.Anatomy of the knee. In: Nicholas JH, Hershman EB, eds. The Lower Extremityand Spine in Sports Medicine. St. Louis, Mo: CV Mosby; 1986.6

Figure 2. Five Types of Meniscal Tears

Reprinted with permission from Ciccoti MG, Shields CL, El Attrache NS.Meniscectomy. In: Fu FH, Harner CD, Vince KG, eds. Knee Surgery. Baltimore,Md: Lippincott, Williams and Wilkins; 1994.21

Anterior cruciate ligament

Medialcollateralligament

Transverse ligament

Lateralmeniscus

Ligament of WrisbergPosterior cruciate ligament

A. Vertical Longitudinal B. Oblique C. Degenerative

D. Transverse (radial) E. Horizontal

Medialmeniscus

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sports injuries.14 Sports in which cutting and pivotingmoves predominate, such as football, soccer, and bas-ketball, lead to the highest incidence of meniscaltears.14-16 Men are 3 times more likely than women tosustain a meniscus tear, probably due to greater num-bers of the former participating in high-risk activities.13

ACUTE, DEGENERATIVE, CHRONIC TEARS

Meniscal tears can be considered acute when asso-ciated with a specific traumatic event or degenerativewhen associated with recurrent microtrauma. Acutemeniscal tears are more common among youngerpatients and in this population are associated withacute ACL injury 33% of the time.17 In patients withan intact ACL, medial meniscal tears are more com-mon than lateral meniscal tears by a ratio of 5:1.13 Thisis thought to be due to the decreased mobility of themedial meniscus, which is tethered to the joint capsuleperipherally. In industrial workers who squat a greatdeal, the ratio of medial to lateral tears is closer to20:1.18 However, in patients with an acute ACL injury,the lateral meniscus is more likely to be torn due toshifting of the lateral condyle on the lateral plateau,which occurs at the time of injury.19

Chronic tears of the meniscus most commonlyoccur in middle-aged and older patients and are oftennot associated with a specific traumatic event. As thefunction of the meniscus gradually decreases over time,concomitant arthritic changes in the articular cartilageof the knee often accompany this presentation.

TYPES OF MENISCAL TEARS

Meniscal pathology can be described based on thetear pattern, length, depth (either partial thickness orcomplete), and stability (ability of the torn segmentto move relative to the body of the meniscus). Fivetypes of pathologic meniscal tears seen viaarthroscopy are shown in Figure 2. This classificationsystem is different from the grading scale used byradiologists (please see “Radiographic Evaluation”below). In practice, most tears of the menisci areeither oblique or vertical longitudinal.20

Vertical longitudinal tears are more common inyounger patients and can be unstable (the torn innersegment can move with knee motion). A bucket-handle tear is a complete vertical tear, which is bynature unstable and can displace toward the center ofthe joint. This will cause the clinical symptoms ofcatching and locking, as well as deficits in knee exten-sion and flexion. Oblique tears can catch between thefemoral condyle and tibia and cause traction on themeniscocapsular junction, producing pain. Complextears are multiplanar, usually degenerative and chronic,and often associated with arthritic changes in the artic-ular cartilage in the medial and lateral joint spaces.

Horizontal tears are more common in older patientsand more likely to be associated with meniscal cysts,which are often palpable at the joint line. Horizontaltears are also the tears most likely to be asymptomatic.Radial tears begin at the inner edge of the meniscus butcan traverse the entire cross section, disrupting theweight-bearing function of the meniscus. All tears havefree edges that may catch between articulating surfacesand cause propagation of the tear further into the bodyof the meniscus. One goal of meniscal surgery is tolimit tear propagation.

CLINICAL EVALUATION

The clinical evaluation should focus on determin-ing whether the patient has a meniscal tear and, if so,whether this tear is causing mechanical symptoms thatwould necessitate surgery. Unfortunately, no onesymptom or clinical test is diagnostic of a meniscaltear; rather, the diagnosis is made based on a compos-ite of symptoms and clinical examination findings.

Patients should be questioned about traumaticevents, knee swelling, and the presence of mechani-cal symptoms including painful knee joint catchingand locking. A subjective feeling of catching duringknee motion could indicate an unstable torn menis-cal fragment sandwiched between the articular sur-faces at a particular knee position that then reducesback to its original position, relieving the catch. Atorn meniscal fragment that displaces toward thecenter of the joint could cause the knee to lock, orprevent further flexion or extension. Classically,locking occurs with a bucket-handle meniscus tearthat displaces and prevents full extension of the knee.Patients also should be questioned concerning thelocation of the pain, as meniscal pain is typically feltalong the medial or lateral joint line. Patients withmeniscal tears also may experience pain with activi-ties that involve weight bearing in maximum kneeflexion, such as squatting.

Patients with patellofemoral pain, with or withoutarthrosis, may describe symptoms similar to those ofa meniscus tear. A sensation of catching or lockingmay occur in the articulation between the patella andthe distal femur, particularly during activities thatload this articulation, such as deep squats or stairclimbing. Sometimes, patients are able to localize thispain to the patellofemoral joint, but often they con-fuse the symptoms with those arising from thetibiofemoral articulation.

CLINICAL EXAMINATION

The clinical examination should begin with aninspection of the knee for effusion and palpation fortenderness followed by assessments of knee range ofmotion, knee ligament stability, and associated

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patellofemoral disorders. Finally, provocative maneu-vers should be done to evaluate for meniscal tears.

Joint Line Tenderness. In patients with intact ACLsand a meniscal tear, 60% to 80% will have tendernessalong the joint line.21 The tenderness should be local-ized as medial or lateral and correlated with the site ofpain experienced with everyday activities. A meniscalcyst also may be present along the joint line. Meniscalcysts are joint capsule outpouchings filled with a gelati-nous substance resembling synovial fluid. Most oftenseen at the lateral joint line, these cysts decrease in sizewith knee flexion and are highly suggestive of anunderlying meniscal tear.22 They are different fromBaker’s cysts, which are larger and often occur posteri-orly in the popliteal fossa. Joint line tenderness is notalways pathognomic of a meniscal tear; it also may beassociated with chondral lesions of either the femoralor tibial articular surfaces or with knee ligament injury.In the presence of an acute injury, such as an ACL tear,joint line tenderness is much less reliable for predictingthe presence of a meniscal injury.23

Range of Motion. The range of motion of the involvedknee should be carefully assessed and compared to that ofthe contralateral knee. Deficits in knee extension or flex-ion should alert the examiner to possible displacedmeniscal tears prohibiting full range of motion.

Evaluation of the Patellofemoral Joint. The patellashould be examined for smooth tracking throughoutknee flexion without excessive medial or lateral devia-tion from the femoral trochlea. Symptoms of catchingor grinding should be localized to either thepatellofemoral joint or the articulation between thefemur and tibia (menisci) if possible. In addition, thepatient should be examined for pain with patellar load-ing. To perform this test, the examiner presses thepatella against the femoral condyle while asking thepatient to slowly contract the quadriceps. The patientshould be asked whether he or she experiences painduring this maneuver and more specifically whetherthis maneuver reproduces the original pain. A positiveresponse to these questions suggests a patellofemoralrather than meniscal etiology.

Specific Maneuvers to Diagnose Meniscal Tears.Several maneuvers have been developed to test specifi-cally for the presence of a meniscal tear. McMurray’stest, described by Smith24 in a previous issue of thisJournal, involves passively flexing the knee from anextended position while internally rotating the footand then repeating the movement with the foot exter-nally rotated.25,26 During this maneuver, 1 of the exam-iner’s hands palpates the joint line; the other handmanipulates the leg. A positive McMurray test isrevealed by a palpable “thud” that occurs when a frag-ment of meniscus catches between the femur and thetibia at some point during the flexion arc. Classically, a

posterior medial meniscus tear will produce a posi-tive result with the leg externally rotated (heel rotat-ed medially), whereas a posterior lateral meniscustear will produce a positive result with the leg inter-nally rotated (heel rotated laterally). McMurray’s testis specific (0.98) but not sensitive (0.16) for diag-nosing medial meniscus tears.27 It is not as accurateat diagnosing lateral meniscal tears, with a positivepredictive value of only 0.29.27 Even if a thud isabsent when performing the test, pain that repro-duces the patient’s symptoms strongly suggests ameniscal pathology.

Apley’s test, also discussed by Smith, was developedto differentiate between meniscal pathology and othersources of intra-articular derangement. The testinvolves having the patient lie prone with the hipextended and knee flexed 90 degrees. Then the physi-cian presses down on the foot while rotating the leginternally and externally (grind maneuver). Pain withthis compressive, shearing grind maneuver indicates ameniscal tear.28 The test is then repeated with distrac-tion rather than compression applied to the leg,unloading the menisci. Pain with distraction and rota-tion indicates some source of pathology other than atorn meniscus.

IMAGING STUDIES

RADIOGRAPHIC EVALUATION

Patients suspected of having a meniscal tear shouldhave radiographs taken of the involved knee. Thoughradiographs will not show the meniscal tear, they willdelineate alternative and concurrent pathologies, suchas a fracture in a patient with an acute knee injury orarthritic changes in a patient with chronic symptoms.Two views of the knee, usually anteroposterior and lat-eral views, can reveal gross pathology such as medial-or lateral-compartment degenerative arthritis or frac-tures. Standard views obtained by an orthopedic sur-geon include a posterior-anterior (P-A) weight-bearingview in 45 degrees of flexion, lateral views in 30degrees of flexion, and an axial “sunrise” view or aMerchant view of the patella. Arthritic changes in themedial and lateral tibiofemoral compartments are bestevaluated on the P-A weight-bearing 45-degree view,whereas patellofemoral arthritis and malalignmentproblems are best evaluated on the axial patella view.

MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is commonlyused to evaluate a meniscal tear. MRI allows evaluationof soft tissue structures in the knee, including the cruci-ate and collateral ligaments, menisci, and patellar ten-don. Osteochondral lesions, patellofemoral disorders,and intra-articular loose bodies often can be seen withMRI.29-32 Meniscal cysts also are easily detected with

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MRI. Normally, the menisci appear as uniformly darkstructures devoid of high-signal areas.

Tears are seen as high-signal areas within the sub-stance of the meniscus. Radiologists use a grading sys-tem to delineate these signal changes, with grade 0being a normal meniscus; grades I and II, high-signalintrameniscal areas that do not abut a free meniscaledge; and grade III a high-signal area that tracks to theedge of the meniscus. Grade III changes are the onlychanges consistent with a clinically significant meniscaltear and, for this reason, care must be used when inter-preting MRI images and reports. Care must also beused when interpreting signal changes in a patient whohas had previous meniscal surgery, as MRI is oftenunreliable in these cases.

The main disadvantages of MRI are the costs asso-ciated with the test and the large number of incidentalmeniscal findings in asymptomatic patients.28 A studycomparing the sensitivity and specificity of a clinicalexamination with an MRI for diagnosing meniscaltears found them to be similar.15 The study highlighted2 important concepts. First, the clinical examinationfindings were not the result of a specific maneuver butrather a composite of (1) the patient’s history as elicit-ed by an experienced orthopedic surgeon and (2) thefindings of several examinations. Second, the MRIscans had a high negative predictive value for excludinga meniscal tear as the cause of knee pain.15,17, 33,34

It is imperative that findings on MRI be correlatedwith a careful history and physical examination beforeattributing the patient’s knee pain to the specific MRIfinding. Also, before ordering an MRI, thought shouldbe given to whether the results of the MRI will changethe treatment. For instance, a patient with an acutebucket-handle tear of the medial meniscus presentingwith a knee extension deficit would, in general, requiresurgery and may not require an MRI prior to surgery.Patients with known meniscal tears typically do notrequire an updated MRI performed prior to surgery.

NONOPERATIVE TREATMENT

Conservative treatment is indicated for patientswith small, stable tears or asymptomatic tears. Othercandidates for conservative treatment are older patientswith concomitant arthritic changes in the joint and nomechanical symptoms, or patients with medical con-traindications to surgery.

Conservative measures should focus on relievingpain through the use of activity modification; oralanalgesics, such as acetaminophen or nonsteroidal anti-inflammatory drugs; postactivity cold therapy; andcompression.

Physical therapy is an important component ofboth the conservative and surgical treatment of menis-cal tears. Physical therapy should focus on preventing

the functional sequelae of a painful knee, such asquadriceps atrophy and knee stiffness. Physical therapyregimens should be designed to regain full range ofmotion of the knee first, followed by gentle progressiveresistance exercises to strengthen the quadriceps andhamstrings. Rehabilitation programs should avoidopen-chain quadriceps-strengthening exercises, such asisolated knee extension against resistance, as these exer-cises may exert too much stress on the patellofemoraljoint. Instead, closed-chain quadriceps exercises involv-ing cocontraction of the hamstrings and quadricepsshould be emphasized.

Physical therapy modalities, such as electrical stim-ulation of the quadriceps and hamstring muscles, ultra-sound, and cryotherapy, may be employed as adjunctsto a core program that develops knee range of motionand strengthens the surrounding muscles.

REFERRAL TO A SPECIALIST

A question often arises regarding when to refer apatient to an orthopedic surgeon or a primary caresports medicine specialist. Certainly an athlete withan acute injury and a knee effusion should be referredto a specialist without delay. A patient with a sus-pected meniscus lesion and mechanical symptomsand signs also should be referred, as partial meniscec-tomy or meniscal repair may substantially benefitsuch a patient. A patient with a suspected or docu-mented meniscal lesion but no mechanical symptomsmay not need to see a specialist initially. Particularlyin the case of degenerative knee osteoarthritis, anextended course of conservative treatment may beindicated. Failure of conservative treatment and inter-ference with activities of daily living would be indica-tions for referral.

SURGICAL TREATMENT

Prior to the 1980s, total meniscectomy was a pop-ular treatment for patients with meniscal injuries. Kingwas the first to notice the degenerative articular carti-lage changes in the knees of patients who had under-gone total meniscectomy.35,36 Fairbank described thedegenerative changes that one can visualize on radio-graphs following total meniscectomy (and presumablyfollowing meniscal tears): squaring of the femoralcondyle, osteophyte formation, and joint space nar-rowing.37 As these findings came to light, the orthope-dic community began to appreciate the relationshipbetween meniscal function and prevention of articularcartilage damage, and gradually moved from totalmeniscectomy to procedures that preserve as muchmeniscal tissue as possible, such as partial meniscecto-my and meniscal repair.

Current surgical treatment of meniscal tears has 2goals: to relieve pain and to limit further degenerative

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changes in the surrounding articular cartilage.Degenerative changes in the articular cartilage are like-ly to start soon after the meniscal tear occurs. Thechanges are due to the inability of the affected segmentto participate in load transmission and shield theunderlying articular cartilage from increased contactstresses. Pain and mechanical symptoms produced by atorn flap of meniscal tissue intermittently interposedand tethered between the articulating surfaces of theknee often respond to simple debridement of the tornmeniscal tissue. However, the well-known associationbetween total meniscectomy and degenerative changesin the articular cartilage compels the surgeon to pre-serve as much functional meniscus tissue as possible.During surgery, steps also are taken to halt tear propa-gation into normal meniscal tissue.

A patient with joint line tenderness, mechanicalknee symptoms, and positive results on specific exam-inations for a meniscal tear, who is adversely affectedby symptoms and has no other explanation for theknee pain, is a candidate for knee arthroscopy and sur-gical management of the meniscal lesion. At this pointsurgical management most often consists of (1) partialmeniscectomy with removal of only the torn fragmentand contouring of the remaining meniscus to preventtear propagation or (2) meniscal repair involving directsuturing of the torn fragment to the meniscal body.Other techniques of surgical management includereplacement of the entire meniscus with an allograftmeniscal implant or bioengineered meniscal implant.Neither of the latter techniques is in widespread use atthis time except in specialized circumstances.

The decision between performing a meniscal repairvs a partial meniscectomy is made based on the patternof the tear, the distance from the rim, concomitant jointpathology, and the age of the tear. The patient’s age,activity level, involvement in sports, and ability to becompliant with the postoperative rehabilitation scheduleare also taken into account. As will be discussed, menis-

cal repair generally involves a longer postoperative reha-bilitation schedule and may not be considered desirableby high-performance athletes who wish to return to par-ticipating in sports as quickly as is possible.

PARTIAL MENISCECTOMY

Partial meniscectomy is indicated in patients whohave tears in the inner 70% of the meniscus, where thetear fragment is mobile and can cause mechanical symp-toms or might propagate further into the body of themeniscus. The procedure is usually performed on anoutpatient basis using arthroscopic instruments. Surgeryusually takes 15 to 45 minutes and is performed usingregional or general anesthesia. Three to 5 small (5 mm)portal incisions are made in various locations overlyingthe knee joint for the introduction of arthroscopicinstruments. With fluid infused through the joint to dis-tend the joint capsule and allow visualization, an arthro-scopic camera is introduced into 1 portal and asystematic inspection of the entire knee joint is per-formed. Other portals are used for introducing variousprobes, manual cutting instruments, and motorizedshavers. After identifying a meniscal tear that is not acandidate for a repair procedure, a partial meniscectomyis performed under camera visualization. The mobilefragments of torn meniscus are debrided back to a stablerim using the cutting instruments and motorized shaver.The resultant rim is then smoothed to prevent propaga-tion of the tear (Figure 3). The instruments are removedand the arthroscopic portals are usually closed using 1suture per portal. Almost all patients are allowed to bearweight as tolerable immediately after the procedure.Most patients use crutches for 1 to 2 days postsurgery.Patients involved in administrative or similarly seden-tary professions often return to work after 1 week ofrecovery. Laborers typically require 2 to 4 weeks beforereturning to full duties. Athletes generally can return totheir sport 2 to 6 weeks following surgery. Long-termfollow-up of patients with partial meniscectomy hasshown that 88% of patients have an excellent clinicaloutcome at 15 years.38

MENISCAL REPAIR

Meniscal repair is indicated only for certain pat-terns of meniscal tear. The tear pattern most amenableto repair is the vertical longitudinal tear. To obtain thenecessary blood supply for healing, the tear must be inthe outer 30% of the meniscus and should be longerthan 1 cm; shorter tears in the periphery may heal ontheir own.

Several techniques are used to repair meniscal tears.Using small incisions to expose the joint capsule, an“inside-out” repair uses suture needles passed throughthe torn meniscus under arthroscopic vision andretrieved on the outside of the knee.39 Vertical mattress

Figure 3. Partial Meniscectomy

A lateral meniscus tear before (left) and after (right) partial meniscectomy.

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sutures are used to reapproximate the torn surfaces.The suture knots are tied down over the external jointcapsule surface (Figures 4 and 5). This technique ismore useful for tears in the posterior aspects of themedial and lateral menisci.

The “outside-in” technique is more useful for tearsin the anterior aspects of the menisci and involvesspinal needles placed across the meniscal tear from out-side the knee.40 The needles are visualized arthroscopi-cally as they cross the torn surfaces. Sutures are thenpassed through the needles to repair the tear using avertical mattress configuration. “All-inside” techniquesinvolve specially developed instrumentation andbiodegradable meniscal “arrows” that provide fixationacross meniscal tears, much like threaded carpentrytacks.41 Ease of use and the fact that no additional inci-sions are necessary for placement make these devicesattractive. However, the fixation they provide is not assecure as that provided by sutures,42,43 making them lessappropriate for higher-demand tears.

Following repair of a meniscal tear, patients usuallyhave restricted weight bearing on the operative leg for2 weeks and must wear a brace. Administrative work-ers may return to work after 1 week, but laborers maybe on restricted duty for 6 to 12 weeks. Athletes mayusually return to their sport within 12 to 16 weeks.

The long-term results of meniscal repair have beenevaluated in patients with at least 10-year follow-up.Johnson et al found that 76% of patients who receivea meniscal repair have excellent symptomatic results at10 years.44

CONCLUSION

Meniscal injuries are common, especially amongathletes. A careful history and physical examinationfocusing on mechanical signs and symptoms areimportant to distinguishing meniscal pathology fromother knee complaints, such as patellofemoral pain. Atypical patient presenting with an effusion, joint linetenderness, and mechanical signs and symptomsshould be referred to a specialist, such as an orthopedicsurgeon or primary care physician specializing in sportsmedicine. A patient with a meniscal tear who has failedconservative treatment also should be referred to a spe-cialist. MRI has excellent sensitivity for diagnosingmeniscal tears but should not replace a careful historyand physical examination. In addition, MRI has a highnegative predictive value for excluding a meniscal tear;a negative MRI should therefore prompt a search forother causes of knee pain.

Conservative treatment is indicated for stablemeniscal tears in patients with low activity require-ments. Patients failing conservative treatment mayrequire surgical management of their meniscal lesion.Partial meniscectomy is often successful at eliminating

a patient’s short-term pain. Meniscal repair is not onlyeffective for relieving short-term pain but also has theadded benefit of limiting further articular cartilagedamage.

Figure 4. The Inside-Out Meniscal Repair

Reprinted with permission from Cannon WD. Arthroscopic meniscalrepair. In: McGint JB, ed. Operative Arthroscopy. Ed 3. Baltimore,Md: Lippincott, Williams and Wilkins; 2003.

Figure 5. Meniscal Repair

At upper left is a displaced bucket-handle tear of the lateral meniscus in afootball player. Shown in upper right is an inside-out repair of the femoralside of the tear using nonabsorbable sutures. At bottom is the inside-outrepair of the tibial side of the tear.

anterior

posterior

x-sect.

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REFERENCES

1. Beaupre A, Checkroom R, Guidepin R, Garneau R,Gerardin H, Cardou A. Knee menisci: correlation betweenmicrostructure and biomechanics. Clin Orthop.1986;208:72-75.

2. Arnoczky SP, Warren RF. Microvasculature of the humanmeniscus. Am J Sports Med. 1982;10:90-95.

3. Mow VC, Fithian DC, Kelly MA. Fundamentals of articularcartilage and meniscus biomechanics. In: Ewing JW, ed.Articular Cartilage and Knee Joint Function: Basic Scienceand Arthroscopy. New York, NY: Raven Press; 1990.

4. Arnoczky, SP, Warren RF. The microvasculature of the themeniscus and its response to injury: an experimental study inthe dog. Am J Sports Med. 1983;11:131-141.

5. Johnson DL, Swenson TM, Livesay GA, Aizawa H, Fu FH,Harner CD. Insertion site anatomy of the human menisci: gross,arthroscopic, and topographical anatomy as a basis for menis-cal transplantation. Arthroscopy. 1995;11:386-394.

6. Warren R, Arnoczky SP, Wickiewicz TL. Anatomy of theknee. In: Nicholas JH, Hershman EB, eds. The LowerExtremity and Spine in Sports Medicine. St. Louis, Mo: CVMosby; 1986.

7. Seedhom BB, Hargreaves DJ. Transmission of the load in theknee joint with special reference to the role of the menisci:Part II: Experiment results, discussion and conclusion. EngMed. 1979;8:220-228.

8. Voloshin AS, Wosk J. Shock absorption of meniscectomizedand painful knees: a comparative in-vivo study. J BiomedEng. 1983;5:157-161.

9. Allen CR, Wong EK, Livesay GA, Sakane M, Fu FH, Woo SL.Importance of the medial meniscus in the anterior cruciate liga-ment deficient knee. J Orthop Res. 2000;18:109-115.

10. Shoemaker SC, Markolf KL. The role of the meniscus in theanterior-posterior stability of the loaded anterior cruciate-defi-cient knee: effects of partial versus total excision. J Bone JointSurg Am. 1986;68:71-79.

11. Hede A, Jensen DB, Blyme P, Sonne-Holm S. Epidemiologyof meniscal lesions in the knee: 1,215 open operations inCopenhagen 1982-84. Acta Orthop Scand. 1990;61:435-437.

12. Nielsen AB, Yde J. Epidemiology of acute knee injuries: aprospective hospital investigation. J Trauma. 1991;31:1644-1648.

13. Baker BE, Peckham AC, Pupparo F, Sanborn JC. Review ofmeniscal injury and associated sports. Am J Sports Med.1985;13:1-4.

14. Kelly MA, Flock TJ, Kimmel JA, et al. MR imaging of theknee: clarification of its role. Arthroscopy. 1991;7:78-85.

15. Muellner T, Weinstabl R, Schabus R, Vecsei V, Kainberger F.The diagnosis of meniscal tears in athletes: a comparison ofclinical and magnetic resonance imaging investigations.Am J Sports Med. 1997;25:7-12.

16. Saal JA. Common American football injuries. Sports Med.1991;12:132-147.

17. Poehling GG, Ruch DS, Chabon SJ. The landscape ofmeniscal injuries. Clin Sports Med. 1990;9:539-549.

18. Ricklin P, Ruttiman A, Delbuono MS. Meniscus Lesion:Practical Problems of Clinical Diagnosis, Arthrography andTherapy. New York: Grune and Stratton; 1971.

19. Duncan JB, Hunter R, Purnell M, Freeman J. Meniscal injuriesassociated with anterior cruciate ligament tears in alpineskiers. Am J Sports Med. 1995;23:170-172.

20. Metcalf RW, Burks RT, Metcalf MS, McGinty JB.Arthroscopic meniscectomy. In: McGint JB, Caspari RB,Jackson RW, Poehling GG, eds. Operative Arthroscopy.2nd ed. Philadelphia, PA: Lippincott-Raven; 1996.

21. Ciccoti MG, Shields CL, El Attrache NS. Meniscectomy. In:Fu FH, Harner CD, Vince KG, eds. Knee Surgery. Baltimore,Md: Williams and Wilkins; 1994.

22. Lantz B, Singer KM. Meniscal cysts. Clin Sports Med.1990;9:707-725.

23. Shelbourne KD, Martini DJ, McCarroll JR, VanMeter CD.Correlation of joint line tenderness and meniscal lesions inpatients with acute anterior cruciate ligament tears. Am JSports Med. 1995;23:166-169.

24. Smith CC. Evaluating the painful knee: a hands-onapproach to acute ligamentous and meniscal injuries.Adv Stud Med. 2004;4:362-370.

25. McMurray TP. The semilunar cartilages. Br J Surgery.1942;29:407-414.

26. Hoppenfeld S. Physical Examination of the Spine andExtremities. Norwalk, Ct: Appleton-Century-Crofts; 1976.

27. Evans PJ, Bell GD, Frank C. Prospective evaluation of theMcMurray test. Am J Sports Med. 1993;21:604-608.

28. Apley AG. The diagnosis of meniscal injuries. J Bone JointSurg. 1947;29:78-84.

29. Laprade RF, Burnett QM, Veenstra MA, Hodgman CG. Theprevalence of abnormal magnetic resonance imaging find-ings in asymptomatic knees. With correlation of magneticresonance imaging to arthroscopic findings in symptomaticknees. Am J Sports Med. 1994;22:739-745.

30. Mandelbaum BR, Finerman GA, Reicher MA, et al.Magnetic resonance imaging as a tool for evaluation of trau-matic knee injuries. Anatomical and pathoanatomical corre-lations. Am J Sports Med. 1986;14:361-370.

31. Reicher MA, Hartzman S, Duckwiler GR, Bassett LW,Anderson LJ, Gold RH. Meniscal injuries: detection using MRimaging. Radiology. 1986;159:753-757.

32. Soudry M, Lanir A, Angel D, Roffman M, Kaplan N,Mendes MG. Anatomy of the normal knee as seen by mag-netic resonance imaging. J Bone Joint Surg Br. 1986;69:117-120.

33. Fischer SP, Fox JM, Del Pizzo W, Friedman MJ, Snyder SJ,Ferkel RD. Accuracy of diagnosis of magnetic resonanceimaging of the knee: a multicenter analysis of one thousandand fourteen patients. J Bone Joint Surg Am. 1991;73:2-10.

34. Herman LJ, Beltran J. Pitfalls in MR imaging of the knee.Radiology. 1988;167:775-781.

35. King D. The function of the semilunar cartilages. J Bone JointSurg. 1936;18:1069-1076.

36. King D. The healing of the semilunar cartilages. J Bone JointSurg. 1936;18:333-342.

37. Fairbank TJ. Knee joint changes after meniscectomy. J BoneJoint Surg. 1948;30B:664-670.

38. Burks RT, Metcalf MH, Metcalf RW. Fifteen year follow up ofarthroscopic partial meniscectomy. Arthroscopy.1997;13:673-679.

39. Henning CE. Arthroscopic repair of meniscus tears.Orthopedics. 1983;6:1130-1132.

40. Warren RF. Arthroscopic meniscus repair. Arthroscopy.1985;1:170-172.

41. Albrecht-Olsen P, Kristensen G, Tormala P. Meniscus bucket-handle fixation with an absorbable Biofix tack: developmentof a new technique. Knee Surg Sports Traumatol Arthrosc.1993;1:104-106.

42. Dervin GF, Downing KJ, Keene GC, McBride DG. Failurestrengths of suture versus biodegradable arrow for meniscalrepair. An in vitro study. Arthroscopy. 1997;13:296-300.

43. Boenisch UW, Faber KJ, Ciarelli M, Steadman JR, ArnoczkySP. Pull-out strength and stiffness of meniscus repair usingabsorbable arrows versus Ti-cron vertical and horizontal loopsutures. Am J Sports Med. 1999;27:626-631.

44. Johnson MJ, Lucas GL, Dusek JK, Henning CE. Isolatedarthroscopic meniscal repair: a long term outcome study(more than ten years). Am J Sports Med. 1999;27:44-49.