The meniscus plays an important role in the func-tion of the knee. Preservation of the meniscus ispreferred if possible when considering treatmentof a meniscus tear. A thorough understanding ofthe anatomy of the meniscus, the structure, themechanics, and other factors of meniscal healingare critical when evaluating the torn meniscus fora reparative procedure. Many options for menis-cus repair exist for the orthopaedist. Optionssuch as open repair or arthroscopically-assistedinside-out techniques have long-term favorableresults. The all-inside techniques are attractivebecause of the decrease in operative time and easeof the technique. Short-term results are positivefor the all-inside technique; however, good long-term data on these techniques are lacking. Fewwell-designed prospective studies exist on any ofthe meniscus repair techniques. Future direc-tions include the potential use of growth factorsand gene therapy to augment meniscus repair.
When an individual presents to the physicianwith signs and symptoms of a meniscal tear,
certain decisions need to be made regardingthe treatment. Although some disorders of themeniscus can be treated nonoperatively, oth-ers require surgery. A few decades ago, themeniscus generally was thought to be unim-portant to the function of the knee. Tears in themeniscus typically resulted in complete exci-sion of the meniscus. Since then there has beenan increasing awareness of the importance ofthe normal meniscus structure. The long-termconsequences of a meniscectomy or even par-tial meniscectomy have been shown to be po-tentially deleterious to the joint surface.18,19,
25,36,42,62,78 Tears in the vascularized portion ofthe meniscus have been shown to possess thepotential to heal and be amenable to repair.
The concept of repairing the meniscus is notnew. The first report of a meniscus repair was in1885 by Annandale.6 Subsequently, there havebeen numerous studies and articles publishedon the treatment of meniscal tears, particularlysince the advent of arthroscopy in the past 30 years.10,18,19,30,62,73,78,87,91 Techniques haveevolved from open repairs to semiopen repairs toall arthroscopic repairs. Devices for repairing themeniscus also have evolved. The current optionsfor fixing a meniscus are numerous and willcontinue to increase into the new millennium.
Meniscus Structure and FunctionThe menisci are semilunar shaped fibrocarti-lage structures on the medial and lateral sides
Meniscus RepairConsiderations in Treatment and Update of Clinical Results
Eric C. McCarty, MD*; Robert G. Marx, MD, MSc** Kenneth E. DeHaven, MD†
From the *Department of Orthopaedics and Rehabilita-tion, Vanderbilt University Medical Center, Nashville,TN; the **Sports Medicine and Shoulder Service, Hos-pital for Special Surgery, New York, NY; and the †De-partment of Orthopaedics, University of Rochester,School of Medicine and Dentistry, Rochester, NY.Reprint requests to Eric C. McCarty, MD, VanderbiltUniversity Sports Medicine, 2601 Jess Neely Drive,Nashville, TN 37212.DOI: 10.1097/01.blo.0000026963.51742.d0
of the knee. Once thought of as vestigial struc-tures, the menisci now are known to be inte-gral components of knee function. They consistof approximately 75% Type I collagen. Thecollagen fibers lie mostly along the longitudi-nal axis, with oblique and radial fibers to en-hance the structural integrity.7 The viscoelas-tic properties of the menisci allow compressiveloads to be dissipated along circumferentialfibers, thereby reducing the impact forces onthe articular cartilage.7
The blood supply to the menisci is impor-tant to understand. The peripheral 20% to 30%of the medial meniscus and the peripheral 10%to 25% of the lateral meniscus are vascular8,9
(Fig 1). Branches from the superior, inferior,and lateral geniculate arteries supply this vas-cular zone. The avascular zone of the menisci,which includes at least the inner 1⁄3 of eachmeniscus, is nourished by synovial fluid diffu-sion. The middle 1⁄3 zone may have some bloodsupply, yet it likely derives most of its nour-ishment from the synovial fluid. The vasculardistribution has important clinical implica-tions for meniscal repair surgery because heal-ing is enhanced greatly in the vascular regions.
The menisci are not fixed on the tibia butactually have anteroposterior (AP) translationwith knee motion. The lateral meniscus trans-lates as much as 9 to 11 mm in the AP plane,whereas the medial meniscus is less mobile,translating only 2 to 5 mm.52 This relative lackof motion may be important clinically as acontributing factor to the increased incidenceof meniscal tears on the medial side.
The primary function of the meniscus is toevenly distribute load across the knee. Forcesacross the knee may be as high as two to fourtimes body weight during walking and as highas six to eight times body weight during run-ning. When the meniscus is loaded in weight-bearing, the meniscal fibers elongate as theyare pushed to the periphery.7 With the knee inextension, approximately 50% of the load istransmitted to the menisci. This is increased toalmost 90% with the knee at 90� flexion.52
Most of the force is transmitted through theposterior horns with flexion past 90�.
The lateral meniscus has been shown totransmit a greater percentage of the load in thelateral compartment (approximately 70%), com-pared with the medial meniscus (approximately50%).1,88 This suggests that patients who havelateral meniscectomy may be at higher riskfor early subsequent joint degeneration. Medialmeniscectomy decreases the contact surface areaof the femoral condyle by 50% to 70% whiledoubling the stresses on the tibial plateau.12
When meniscal integrity is compromised, ab-normal articular contact stresses result, leadingto increased wear of the articular cartilage andearly degenerative changes. The more meniscaltissue that is excised, the greater the loss of con-tact surface area and the greater the increase inpeak local contact stresses. The clinical impor-tance of this initially was described by Fair-bank36 as he found loss of articular cartilage,flattening of the femoral condyles and osteo-phytes in meniscectomized knees.
The menisci also play a role in knee stabil-ity. They deepen the socket of the tibia to bet-ter conform to the ovoid shape of the femoralcondyles. Isolated medial or lateral meniscec-tomy does not result in significant increases in
Number 402September, 2002 Meniscus Repair 123
Fig 1. A frontal section, 5-mm thick, of the medialknee compartment using the Spalteholz technique,shows vessels from the perimeniscal capillaryplexus (PCP) penetrating the periphery of themedial meniscus (Magnification, �3). F � femur, T � tibia (Reprinted with permission from ArnoczkySP, Warren RF: Microvasculature of the humanmeniscus. Am J Sports Med 10:91, 1982.)
AP translation. However, the menisci act assecondary stabilizers in the anterior cruciateligament deficient knee.54 The posterior hornof the medial meniscus particularly is impor-tant for this function because it acts as a wedgeto resist anterior translation.16,51
Finally, the meniscus has a role in joint lu-brication. During loading of the knee, whenthe meniscus is compressed, synovial fluid isdriven into the articular cartilage. This form oflubrication significantly reduces the coefficientof friction in the knee.82
Healing of the MeniscusThe peripheral meniscal blood supply is key tothe healing of the meniscus. Numerous experi-mental and clinical studies have shown a pe-ripheral blood supply that is capable of produc-ing a healing response similar to that seen inother connective tissues.8,22,25,39,42,94 Initially,healing occurs by the formation of fibrovascu-lar scar tissue. This tissue gradually matures toa fibrocartilage over several months.7,26 Most ofthe studies that have examined meniscal heal-ing have focused on vertical and longitudinaltear types.4,18,19,31,40,46,47,58,59,62,71,77 Radial tearsextending to the synovium also heal in a simi-lar fashion.62 However, these types of healedtears may not perform adequately from a bio-mechanics standpoint. Newman et al62 foundthat despite gross and histologic healing in ra-dial tears, the circumferential collagen fiberswere not restored to their original length and,therefore, the ability to transmit load was notmaintained.
Evaluation and Decision Making inTreatment of a Meniscus TearNumerous factors are involved in the determi-nation of treatment of a meniscal tear. In as-sessing these factors one has to be cognizantof meniscal biomechanics including the role inload transmission and congruity of the knee,as discussed previously. Because of the im-portance of intact functional meniscus tissue,the first goal is to preserve as much of the vi-able tissue as is possible. Therefore, decisionson the type of treatment should reflect this.
Factors of the meniscal tear that must be takeninto consideration include the location, length,tear pattern, and stability of the tear, and anydamage to the integrity of the meniscus body.27
Other factors to consider are the patient’s age,presence of degenerative tissue (mucoid degen-eration), concurrent intraarticular injuries, in-tegrity of the anterior cruciate ligament, andchronicity of the tear.
When assessing the patient with a sus-pected meniscus tear, history and physical ex-amination may assist in making the diagnosisof a tear, but the exact site and potential for re-pairability may not be determined clinically.Double contrast arthrography traditionally hasbeen an excellent method for the evaluation ofthe medial meniscus. However, magnetic res-onance imaging (MRI) has largely replacedarthrography as the imaging modality of choicefor the menisci because the accuracy has beenshown to be greater than 90%.34,57,69 Magneticresonance imaging is not routinely requiredfor the diagnosis of all meniscal tears beforearthroscopic surgery is done. Although mostsurgical decisions should be based on the phys-ical examination and history, the MRI scan pro-vides additional information that may proveimportant regarding the status of the ligamentsand articular cartilage and the location of themeniscus tear.68 Despite the accuracy of MRI todetect a tear, there have not been any studiesthat show that an MRI scan can help predict thereparability of tears. Additionally, false-nega-tive MRI studies often are encountered in mostperipheral tears, which are best for repair. Thecharacteristics of the tear can be assessedarthroscopically using traditional anterior lat-eral and medial portals. A posterior portal oc-casionally is necessary to observe the posteriorhorn of the medial meniscus. A probe is used toassist in the assessment of the tear.
Suitability for RepairThe location of the tear is critical because tearsin the vascular zone of the meniscus are suit-able for repair if the meniscal tissue is of ade-quate quality. Typically, this involves a tear inthe peripheral 1⁄3 of the meniscus. Current tech-
Clinical Orthopaedics124 McCarty et al and Related Research
niques have pushed the limits to allow sometears of the central and middle 1⁄3 zones to berepaired. If vascularity of the meniscus is seenwith observable bleeding in the tear area, a re-pair should be considered. DeHaven27 consid-ers tears in the peripheral 3 mm as vascular,those 5 mm or more from the periphery as avas-cular, and those between 3 and 5 mm as vari-able in vascularity. The area in the posterolat-eral aspect of the lateral meniscus around thepopliteus tendon is a watershed area with rela-tive hypovascularity even in the peripheral1⁄3.8,63 In areas with marginal vascularization,abrasion of the meniscal tissue and/or a fibrinclot may be used to enhance healing of a re-pair.10,73,78,87 van Trommel et al87 documentedsuccessful healing in five patients with radialtears in the hypovascular zone of the lateralmeniscus using a fibrin clot.
The pattern, the length, and the stability ofthe tear all play important roles in decision-making. If the circumferential hoop fibers re-main intact, there is a greater chance for heal-ing than when they are disrupted, such as in acomplete radial tear.62 Radial tears in generalare less amenable to repair, although somecomplete tears do warrant attempts at repair,especially when the alternative is a subtotalmeniscectomy. Short inner radial tears (� 5mm) usually do not heal, but often can be leftalone because they may be asymptomatic.30,91
Bucket handle tears that are complex with ra-dial components, often seen in chronic cases,have more difficulty healing with repair thansimple acute bucket handle tears.19 Radial tearsat the posterior horn heal better than those in themiddle part of the meniscus secondary to thevascularity in this region.19 Fitzgibbons andShelbourne37 reported that posterior horn avul-sions of the lateral meniscus may result in noclinical symptoms when left alone in conjunc-tion with an anterior cruciate ligament recon-struction. Longitudinal (vertical) tears in theperiphery are most amenable to repair.18,19,62
Some authors think that stable tears less than1 cm in length can be left alone.19,93 Stabletears have been defined as those in which thecentral portion cannot be displaced more than
3 mm.91 Longitudinal tears that are stable andin the peripheral 2⁄3 often can be left alone, par-ticularly if they are less than 5 mm in length.30
Partial thickness tears of various types, partic-ularly longitudinal tears, usually can be leftalone if they are less than 5 mm in length.30
Oblique and horizontal tears may have diffi-culty healing.
Repair of the meniscus has been shown to bemore successful when done in conjunction withan anterior cruciate ligament reconstruction(62%–96% healing rate) versus no anterior cru-ciate ligament reconstruction (17%–62%).27,78,89
The reasons for this are likely the stability pro-vided by the anterior cruciate ligament recon-struction and the favorable healing environmentfrom the hemarthrosis incurred during ante-rior cruciate ligament reconstruction.24,56,60,93
As mentioned previously, Fitzgibbons and Shel-bourne37 showed that numerous of lateral menis-cal tears remain asymptomatic when left aloneat the time of anterior cruciate ligament re-construction. In a smaller series, Orfaly et al65
reported similar results.Any significant injury to the meniscus body,
such as a complex tear, numerous cleavage tears,change in the meniscal body contour, or degen-erative tearing may render any repair effortfutile. The problem with such injuries to themeniscus body is the structural integrity of themeniscus is damaged and the vascularity maybe impaired.27 Additionally, degenerative tearsare difficult to hold with meniscal repair mater-ial.49 Older individuals often have a degenera-tive component to their tears. The degenerativeportion should be debrided and repair attempteddepending on the type of tear and age of the in-dividual. In addition to a meniscal tear, articularcartilage degeneration may be present in theolder person. In this type of patient, a meniscalrepair may be ill-advised.19 The chronicity ofthe tear also plays a role in the amount of de-generative change found and the complexity ofthe tear. Some authors have reported betterhealing in acute tears than in chronic tears.24,43
Although this may be true, there has not beenconclusive evidence that a tear more than 2 or 3months old will have impaired healing.
Number 402September, 2002 Meniscus Repair 125
Repair Techniques and Review of theLiteratureTypes of repair include the time honored openrepair and arthroscopic techniques of the inside-out and outside-in suture repairs and the all-inside techniques. Inside-out and outside-in re-pairs involve a mini-incision and securing themeniscus to capsule with suture. The all-insidetechnique entails many options including arthro-scopic suture tying and numerous absorbablefixation devices with such names as arrow, fas-tener, dart, and staple.2,17,21,28,35,46,58
Open Repair
Open repair of meniscus tears has been shownto have successful long-term results.29,31,61,70
The technique consists of making a small in-cision similar to that made in an arthroscopicinside-out meniscus repair. The major differ-ence is the capsule and synovium are incisedin the open repair so that observation of thetear can be made (Fig 2). No prospective stud-ies have been published from results using thistechnique. The open repair has been done suc-cessfully by the senior author (KED) since1976. Long-term results published by De-Haven et al31 showed a survival rate of re-paired menisci of 79% after 10 to 13 years. Inthis retrospective series of 33 open meniscus
repairs, the menisci in stable knees performedbest. Another retrospective series by Muellneret al61 documented a survival rate of repairedmenisci at 91% after a mean followup of al-most 13 years. Of 22 patients, only two hadretears and these occurred in unstable knees.Magnetic resonance imaging also was done onall the patients and was found to be unreliablein assessing the healed nature of the meniscusbecause more than 1⁄2 of the menisci had at leasta Grade III signal alteration. Rockborn andGillquist70 compared results of 31 patientswho had open repair with a matched group ofhealthy subjects. After a 13-year followup,80% of patients had normal knee function fordaily activities. The incidence of low-graderadiologic changes was similar between bothgroups.
Currently, the specific indications for theopen repair technique are a posterior medialmeniscus tear (within 2 mm of the meniscosy-novial junction) encountered in a tight medialcompartment. The visibility of the meniscusfrom an anterior portal is very difficult in theextremely tight knee and the all-inside tech-nique with knot tying can be challenging.
Arthroscopic Inside-Out Repair
The inside-out meniscal repair technique in-volves fixation of a tear by placing suturesfrom inside the knee to a protected area on theoutside of the joint capsule. The sutures aretypically on long needles with either absorbableor nonabsorbable 2–0 sutures placed from an-terior portals under arthroscopic observation.Cannula systems of various types are used toplace the sutures at different angles and loca-tions on the meniscus (Fig 3). The ability toachieve consistent perpendicular suture place-ment through the meniscal tear in the posteriorhorn gives this method an advantage over someof the other techniques. However, this alsocarries some risks. A neurovascular injury ispossible while placing the needle from insidethe joint to outside the joint. A posterior inci-sion is required to place a retractor to protectthe neurovascular structures when using thistechnique.
Clinical Orthopaedics126 McCarty et al and Related Research
Fig 2. Open meniscus repair shows the smallarthrotomy made with repair of the meniscus tothe capsule with sutures. (Reprinted with permis-sion from Miller M: Atlas of meniscal repair. OperTech Orthop 5:70–71, 1995.)
Inside-out repairs have yielded favorable re-sults in numerous published reports. Almost allof the studies have been retrospective.21,40,45,60
The success rates of the studies based primar-ily on clinical results have ranged from 73% to91%.13,15,18,33,47,48,66,77,83 These studies haveexamined only one technique without any com-parison. In a comparison study, Hanks et al40
retrospectively reviewed open repairs versusarthroscopic inside-out repairs. After an aver-age of 4.2 years, there was no statistical differ-ence between the two groups in terms of fail-ure rates (11% open versus 8.8% inside-out).Anterior cruciate ligament deficient knees had ahigher failure rate.
Numerous studies have used more objec-tive means to evaluate the healing of menis-
cus repairs rather than only clinical results.These studies used second-look arthroscopyto evaluate inside-out repairs.4,44,45,50,55,74,76,78,86
Horibe et al45 evaluated 132 meniscal repairs.Seventy-three percent of the menisci had com-plete healing. The other 17% had incompletehealing but only nine patients had symptoms re-lated to the meniscus such as locking, swelling,or pain. Tenuta and Arciero84 evaluated 54meniscal repairs with a second look. Sixty-five percent were healed completely, 16% hadincomplete healing, and 19% did not heal.Repairs with a concomitant anterior cruciateligament reconstruction had an increased heal-ing rate (90%) versus repairs done for an iso-lated tear in an anterior cruciate ligament sta-ble knee (57%). Rosenberg et al74 found 83%(24 of 29) meniscus repairs were healed at thetime of the second look. Four of the five failedrepairs occurred in anterior cruciate ligamentdeficient knees. Kimura et al50 evaluated 46 of137 repairs with repeat arthroscopy and re-ported an 83% healing rate. Asahina et al11
examined 98 knees with repeat arthroscopy:74% had complete healing, 13% had incom-plete healing, and 12% had no evidence ofhealing. Decreased healing rates were observedin menisci repaired in the central 1⁄3 zone andthose that had been locked or could be lockedby probing at the time of repair.
Similar findings of decreased healing in thecentral zone of the meniscus were found byRubman et al.76 They examined only patientswith repairs involving the central avascular re-gion of the meniscus. Ninety-one menisci wereevaluated with repeat arthroscopy and only25% had complete healing and 38% had incom-plete healing.
Other studies have used a combination ofeither second look arthroscopy, arthrograms,or both. Van der Reis and Cannon86 reportedtheir experience of 172 inside-out meniscal re-pairs. Either second look arthroscopy (131 re-pairs) or arthrograms (41 repairs) were done toevaluate healing. Satisfactory anatomic heal-ing (� 50%) was evident in 70% of the repairs.However, when assessed clinically, 88% ofthe repairs had no symptoms and were deemed
Number 402September, 2002 Meniscus Repair 127
Fig 3. Inside-out arthroscopic repair shows su-tures placed via long needles through cannulasystem into the meniscus and retrieved posteriorlythrough a small incision to the capsule. (Reprintedwith permission from Miller M: Atlas of meniscalrepair. Oper Tech Orthop 5:70–71, 1995.)
clinically healed. Scott et al78 prospectivelyexamined 178 repairs with either arthroscopyor arthrography and found 61.8% with evi-dence of healing, 16.9% with incomplete heal-ing, and 21.3% with no healing. Cannon andVittori24 found an overall 82% success rate inhealing. Meniscus repairs done in conjunctionwith anterior cruciate ligament reconstructionhad an even better rate of healing at 93%,whereas isolated repairs in anterior cruciateligament stable knees were only 50% success-ful.24 Miller55 also used either arthroscopy orarthrography to evaluate 47 patients and re-ported a success rate of 91%.
In one of the few prospective studies, Alparand Bilsel4 prospectively followed up patientswith peripheral longitudinal tears of the poste-rior horn. At repeat arthroscopy, 96% (48 of50) of the repairs had healed. All 48 patientswere symptom-free.
Arthroscopic Outside-In Repair
Outside-in meniscal repairs use spinal needlespassed from outside of the joint to inside thejoint under arthroscopic observation (Fig 4).The needles are passed through the meniscusrim and then through the meniscus body frag-ment. Suture material then is passed through thespinal needle. The suture then is retrieved by oneof two methods. One method uses a metal snarethrough another needle retrieving the suture.This suture then is tied outside the joint over thecapsule. Alternatively the suture is retrievedthrough the anterior portal. Knots then are tiedon the end of the suture, which is pulled backinto the joint, and traction of the knot against themeniscus body fragment reduces and holds thefragment. Individual sutures can be passedthrough the inferior or superior surfaces of themeniscus, and adjacent sutures are tied to eachother over the capsule. This method is useful fortears in the anterior or body of the medial or lat-eral meniscus. This technique does not work fortears near the posterior horn. A theoretical ad-vantage of this technique is the avoidance ofplacing the neurovascular structures at risk.
Excellent clinical results in 98.6% of pa-tients were reported by Morgan and Cass-
cells59 in their examination and review of symp-toms of patients who had outside-in meniscalrepair. Their followup from 12 to 28 months of70 patients included only one retear that oc-curred 2 months after the initial procedure. Ina later, more extensive study, Morgan et al60
evaluated 74 outside-in meniscal repairs withsecond look arthroscopy (of 353 outside-inmeniscus repairs). Sixty-five percent of thesewere healed completely, 16% completely failed,and 19% had incomplete healing. Ninety-twopercent (11 of 12) of the failures involved theposterior medial meniscus. Rodeo and Senevi-ratne72 reported on the results at the Hospitalfor Special Surgery involving 90 patients us-ing objective criteria such as MRI, computedtomography (CT) arthrography, or arthroscopyto assess outcome. Eighty-seven percent of thepatients had successful outcomes as defined
Clinical Orthopaedics128 McCarty et al and Related Research
Fig 4. Outside-in arthroscopic repair shows thattwo sutures placed through a spinal needle pen-etrating the meniscus are tied outside of the can-nula and brought back in with secure tying of thesuture through a small subcutaneous incision.(Reprinted with permission from Rodeo S, WarrenRF: Meniscal repair using the outside-to-insidetechnique. Clin Sports Med 15:469–481, 1996.)
by no symptoms and complete or partial ob-jective healing. The failure rate was higher inunstable knees (five of 13) versus stable knees(five of 33) and in those with medial repairs(11 of 72) versus lateral repairs (one of 18). Inanother study from the same institution, vanTrommel et al87 also used objective criteria(MRI, arthrography, or arthroscopy) to assesshealing. After an average of 15 months, com-plete healing occurred in 45% and partial heal-ing in 32% of repairs. Poor healing with theoutside-in technique was observed in patientswith tears into the posterior horn of the medialmeniscus.
Plasschaert et al67 retrospectively reviewedthe healing rate, and reported a 74% survivalat a mean followup of 3.5 years. Similar re-sults were reported by Mariani et al53 with77.3% clinically good results at an averagefollowup of 28 months. Valen and Molster85
reported the least favorable results. They re-ported a cumulative survival rate of 50% at 5-year followup in 51 patients. However, as theauthors noted, their indications for repair wereextensive including attempts at repairing tearsin the white-white zone.
Arthroscopic All-Inside Repair
Arthroscopic all-inside meniscal repair tech-niques recently have become popular becausethey seem to avoid many of the potential com-plications of other meniscal repair techniquesand decrease operative time. This may be themost common meniscus repair technique today,yet it is one of the least documented. The popu-larity of this method has increased as numerousdevices and techniques have been introduced.
In 1991 Morgan58 first described the all-in-side arthroscopic meniscus repair technique.He described a posterior cannula and the use ofa suture passer to pass monofilament ab-sorbable suture through posterior horn menis-cus tears. Arthroscopic knots then were tied tosecure the tissue. The technique is effective,yet technically demanding. Subsequently, var-ious devices have been developed to avoid anyposterior incisions. The T-Fix anchor17,21,35
was introduced in the mid1990s. This was de-
veloped to allow secure fixation of the menis-cus with complete arthroscopic observation.Any posterior incisions were avoided andplacement of the anchor was deemed easy. Thesuture anchor consists of a suture fixed aroundthe waist of a small nonbiodegradable bar,which is introduced across the tear site. A sec-ond anchor is placed near the first anchor. Thetwo sutures then are tied. Arthroscopic knot ty-ing skills are mandatory for this technique.
Results from use of the T-Fix have been fa-vorable. Two short-term prospective studieshave been published on the use of this device.Barrett et al17 followed up 20 patients with 21meniscus repairs for a minimum of 1 year. Allrepairs were done in conjunction with an ante-rior cruciate ligament reconstruction. Four pa-tients (19%) remained symptomatic and wereconsidered to have failed clinical results.Three of these four patients had complex hor-izontal tears in the central 1⁄3 of the meniscus.Escalas et al35 followed up 20 patients for 6months. Ninety percent of the group returnedto their preoperative activity levels or betterwith resolution of symptoms. No complica-tions were observed with the device.
Additional development of all-inside menis-cus repair devices has brought forth bioab-sorbable devices that eliminate any arthro-scopic suture tying. Again, published reportson the clinical success of these devices arelimited.2,46 Two published studies have re-ported the short-term results of the meniscusarrow. The arrow is a bioabsorbable devicewith barbs that are placed across a meniscaltear (Fig 5). Hurel et al46 retrospectively fol-lowed up 25 patients (26 repairs) for an aver-age followup of 16.7 months. These patientshad an all-inside repair using the absorbableBiofix arrow fixation device. Eighty-eight per-cent of the patients had good or excellent re-sults. In two patients, soft tissue irritations ap-peared secondary to the arrow. A prospectiverandomized study by Albrecht-Olsen et al2compared inside-out meniscal repair withmeniscus repair using the arrow. The study in-cluded 68 patients. A second look arthroscopywas done on 65 patients (96%); however, the
Number 402September, 2002 Meniscus Repair 129
followup was only 3 to 4 months. The twogroups were well matched. Postoperative reha-bilitation was identical for the two groups withnonweightbearing for 5 weeks. The operativetime for the patients who received arrows (30.3minutes) was half that of the operative time forpatients who received sutures (59.8 minutes).At the second arthroscopy, 91% of the tears inthe patients who received arrows had com-pletely or partially healed compared with 75%in the patients who received sutures (p � 0.11).Two infections occurred in patients who re-ceived sutures whereas no infections occurredin the patients who received arrows.
Recently, numerous case reports document-ing complications have been reported with useof the arrow device for meniscus repair. Severalreports have described grooves or scuffs in thearticular surface corresponding to the locationof the arrow on the adjacent meniscus.5,75,79
Transient posterior knee pain also has been as-sociated with the arrow implants.92 Breakageand migration of the implant has been de-scribed.23 Other reports have presented cases ofthe arrow causing a subcutaneous foreign bodyand a cystic hematoma.41,64
The pullout strength of the arrow devicehas been studied in vitro. It has been shown tohave approximately equivalent pull-out of onehorizontal suture with 0 Maxon3 and approxi-
mately 50% the pull-out of a vertical suture of2–0 Ethibond.32
Rehabilitation After RepairThere are many views on rehabilitation aftermeniscus repair. Traditionally, an individualwith a meniscal tear has been treated with im-mobilization, no weightbearing, or both.29,31,60,78
DeHaven et al29,31 published good results withthis type of aftercare and currently recom-mend 2 weeks of immobilization with the kneein extension for patients with isolated re-pairs.28 This is followed by limited motion(10�–80�) for 2 additional weeks, followed byunrestricted motion. A patient with a meniscalrepair done in conjunction with an anteriorcruciate ligament reconstruction is allowedimmediate motion. Weightbearing is limitedsignificantly until 6 weeks for patient with iso-lated repairs and patients with repairs done inconjunction with an anterior cruciate ligamentreconstruction. DeHaven et al29,31 think thatthe repair needs to be additionally protectedfrom heavy stresses for at least 6 months aftersurgery. This includes refraining from agilitydrills, full-speed running, and full squats.
Other authors advocate a more acceleratedrehabilitation program.14,15,80 Shelbourne etal,80 Barber,14 and Barber and Click15 reportedgood results with immediate range of motion
Clinical Orthopaedics130 McCarty et al and Related Research
Fig 5A–B. (A) All-inside arthroscopic repair using the arrow technique is shown. (B) All-inside arthro-scopic repair after placement of three arrows is shown. (Reproduced with permission of Bionx Implants,Blue Bell, PA.)
A B
and weightbearing as tolerated after meniscalrepair. These authors think that activity re-strictions are unnecessary after repair of themeniscus. Return to full activity was reportedat an average of 10 weeks in the study ofShelbourne et al80; however, the percentageof patients who achieved full activity was notreported.
Concepts are continuing to evolve regard-ing rehabilitation after meniscal repair. Cur-rently, there is not adequate prospective datasupporting either the traditional conservativemethod of postoperative care after meniscalrepair or accelerated rehabilitation. However,accelerated rehabilitation certainly is attrac-tive, particularly to the athlete who would liketo return to his or her sport early. The methodof fixation and technique and the presence ofanterior cruciate ligament reconstruction andpostoperative rehabilitation must be consid-ered to duplicate the reported results.14,15,80
Clearly, more prospective, especially prospec-tive comparative or randomized studies areneeded to make scientific judgments.
Future Directions in Meniscal RepairTechniques and devices continue to be devel-oped for the repair of the meniscus. Recent re-search in the laboratory is focusing more on thebiology of healing and techniques to stimulateor augment that healing.20,71,81,90 Techniquessuch as trephination of meniscal tissue, rasping,and the use of a fibrin clot have been used toaugment repair of the meniscus.10,73,78,87 In-vestigations have targeted growth factors andgene therapy to enhance healing of the menis-cus.20,71,81,90 Various growth factors have beenshown to stimulate meniscal cell migration andmatrix synthesis. It may be possible that fibrinclot can be used as a carrier vehicle for growthfactors or even cultured fibrochondrocytes. Tis-sue culture may be an avenue to grow the cellsto augment and grow in the meniscal tear de-fect. Techniques of gene therapy have shownthe ability to do in vitro transfer of genes intomeniscus cells and then directly into meniscustissue in vivo.38 With this technology, the pos-sibility exists that genes could be transfected
into meniscus cells, stimulating the productionof various growth factor and matrix compo-nents. These growth factors could direct cellproliferation and cell matrix production in thehealing meniscus.
Cell-based techniques will continue to evolveand likely will provide exciting options for theorthopaedist to consider when confronted withmeniscus tears in the future. Advances in tech-nology might allow bioabsorbable meniscusfixation implants to be impregnated with menis-cal tissue stimulating (growth) factors. Otherpossibilities for meniscal repair might includethe use of collagen bonding with somethingsuch as ultraviolet light or laser.
The treatment of a meniscus tear involvesthe consideration of multiple factors. Compre-hension of the mechanics and anatomy of themeniscus are important in the decision mak-ing. The peripheral 1⁄3 of the meniscus is vas-cularized and most amenable to repair. Addi-tionally, a meniscus repair done in conjunctionwith an anterior cruciate ligament reconstruc-tion has been shown to have an increased rateof healing.5,23,41,64,75,79,92 Favorable long-termresults regarding meniscus repair have beendocumented only in the open or arthroscopicinside-out technique. Outside-in and all-insidetechniques are promising in the short-term re-sults, but lack sufficient long-term results to bewidely subscribed to. Many reports have doc-umented some complications with the use ofsome of the bioabsorbable devices used in theall-inside repair technique.5,23,41,64,75,79,92 Thereremains some controversy regarding rehabilita-tion after meniscus repair. Some authors favor aconservative approach with minimal weight-bearing and minimal motion whereas others ad-vocate a more accelerated program consisting ofearly motion and weightbearing. Good resultshave been documented with both approaches.
Despite a continual advancement of tech-niques during the past 2 decades, there still aremany questions that remain, particularly withnewer techniques and with rehabilitation. Ad-ditional studies done in a prospective random-ized fashion are recommended to elucidatethese questions.
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