Meniscal fixation with an absorbable staple. An experimental study in dogs

Animal models used in meniscal repair research from ex vivo to in vivo: A systematic review

This systematic review, registered with Prospero, aims to identify an optimal animal model for meniscus repair research, moving from ex vivo experimentation to in vivo studies. Data sources included PubMed, Medline, all Evidence-Based Medicine Reviews, Web of Science, and Embase searched in March 2023. Studies were screened using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Extracted data including animal model, type of experiment, type of tear, surgical techniques, and measured outcomes, were recorded, reviewed, and analyzed by four independent reviewers. The SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) Rob tool was used for critical appraisal and risk of bias assessment. Out of 11,719 studies, 72 manuscripts were included for data extraction and analysis; 41 ex vivo extra-articular studies, 20 ex vivo intra-articular studies, and only 11 in vivo studies. Six animal models were employed: porcine, bovine, lapine, caprine, canine, and ovine. Longitudinal lesions were the most frequently studied tear pattern and sutures the most common repair technique. Studied outcomes focused mainly on biomechanical assessments and gross observations. This systematic review can guide researchers in their choice of animal model for meniscus repair research; it highlighted the strengths of the porcine, caprine, and bovine models for ex vivo cadaveric studies, while the porcine and caprine models were found to be more suited to in vivo studies due to their similarities with human anatomy. Research teams should familiarize themselves with the advantages and disadvantages of various animal models before initiating protocols to improve standardization in the field.

Articular contact pressures of meniscal repair techniques at various knee flexion angles

Articular cartilage injury can occur after meniscal repair with biodegradable implants. Previous contact pressure analyses of the knee have been based on the tibial side of the meniscus at limited knee flexion angles. We investigated articular contact pressures on the posterior femoral condyle with different knee flexion angles and surgical repair techniques. Medial meniscus tears were repaired in 30 fresh bovine knees. Knees were mounted on a 6-degrees-of-freedom jig and statically loaded to 200 N at 45 degrees, 70 degrees, 90 degrees, and 110 degrees of knee flexion under 3 conditions: intact meniscus, torn meniscus, and meniscus after repair. For each repair, 3 sutures or biodegradable implants were used. A pressure sensor was used to determine the contact area and peak pressure. Peak pressures over each implant position were measured. Peak pressure increased significantly as knee flexion increased in normal, injured, and repaired knees. The change in peak pressure in knees with implant repairs was significantly higher than suture repairs at all knee flexion angles. Articular contact pressure on the posterior femoral condyle increased with knee flexion. Avoidance of deep knee flexion angles postoperatively may limit increases in articular contact pressures and potential chondral injury.

A cyclic testing comparison of FasT-Fix and RapidLoc devices in human cadaveric meniscus

INTRODUCTION

Cyclic testing may provide a more valid depiction of how arthroscopic meniscal repairs will withstand the forces of activities of daily living (ADLs) and therapeutic exercises early post-surgery than single cycle load to failure testing. This study compared the meniscal fixation provided by vertically or horizontally placed FasT-Fix devices to horizontally placed RapidLoc devices under submaximal cyclic test conditions.

MATERIALS AND METHODS

Eighteen human cadaveric menisci were divided into three groups of six specimens. A scalpel was used to create a 2 cm lesion at 3 mm from the outer edge of the posterior third of each specimen. Merselene tape loops were placed around each side of the lesion and the tears were repaired using two vertical FasT-Fix, two horizontal FasT-Fix, or two RapidLoc devices. Cyclic testing (5-50 N at 1 Hz for 500 cycles) was performed on a servo hydraulic device. One-way ANOVA and Scheffe post-hoc tests were used to evaluate group differences (P < 0.05).

RESULTS

The vertical FasT-Fix group had less displacement over the initial ten loading cycles compared to the RapidLoc group (P = 0.004), but did not differ from the horizontal FasT-Fix group (P = 0.07). At 50, 100, 200, 300, 400, and 500 cycles, the vertical FasT-Fix group had less displacement than the horizontal FasT-Fix or RapidLoc groups (P < or = 0.004). At each interval the vertical FasT-Fix group had greater relative stiffness than the other groups (P < or = 0.009).

CONCLUSIONS

The vertical FasT-Fix group had comparatively less displacement (primarily repair site gapping) and greater relative stiffness.

Biomechanical evaluation of meniscal repair systems: a comparison of the Meniscal Viper Repair System, the vertical mattress FasT-Fix Device, and vertical mattress ethibond sutures

BACKGROUND

The biomechanical characteristics of the Meniscal Viper Repair System have not been previously studied.

HYPOTHESIS

Comparable meniscal lesion fixation standards will exist among the Meniscal Viper Repair System, the vertical FasT-Fix device, and vertical mattress sutures.

STUDY DESIGN

Controlled laboratory study.

METHODS

Porcine menisci (3 groups of 7 menisci each) were repaired using different devices. A servohydraulic device cycled each construct between 5 N and 50 N for 500 cycles before load to failure (5 mm/min). Group differences were evaluated with 1-way analysis of variance and Tukey post hoc tests.

RESULTS

During cyclic testing, the vertical mattress suture group (2.3 +/- 0.2 mm) showed less mean displacement than did the vertical FasT-Fix or the Viper system groups (3.9 +/- 0.7 mm and 3.9 +/- 0.5 mm, respectively); the vertical mattress suture group (21.8 +/- 2 N/mm) also displayed superior mean stiffness to the vertical FasT-Fix or the Viper system groups (13.2 +/- 2 N/mm and 13.1 +/- 1.8 N/mm, respectively). During load-to-failure testing, the vertical FasT-Fix group (145.9 +/- 9 N) withstood greater mean loads than did the Viper system group (111.2 +/- 30 N), but it did not differ significantly from loads withstood by the vertical mattress suture group (133.4 +/- 10 N). The Viper system and vertical FasT-Fix groups (14.6 +/- 2 N/mm and 12.1 +/- 1 N/mm, respectively) displayed superior mean stiffness to the vertical mattress suture group (9.8 +/- 0.5 N/mm) during load-to-failure testing.

CLINICAL RELEVANCE

Standard vertical mattress sutures provided superior fixation during cyclic loading compared with the 2 all-inside methods of suture fixation, suggesting a potential for better meniscal lesion healing with vertical mattress sutures when confronted with the stresses associated with early, progressive rehabilitation activities. Stronger sutures and less meniscal segment purchase in tears located 3 to 4 mm from the periphery may contribute to the failure of the Viper repair system.

Meniscal repair using the Polysorb Meniscal Stapler XLS

We present our technique of repair of meniscal tears in 11 patients using a newly designed stapler, the Polysorb Meniscal Stapler XLS (USS Sports Medicine, Norwalk, CT), to increase the effectiveness and ease of repair of tears in the vascular zone while limiting potential complications. The low-profile stapler comes with a reloadable pistol grip device and a disposable straight or 15 degrees upcurved shaft with a single preloaded 10-mm staple. Standard anteromedial and anterolateral portals were used, along with a superomedial portal for inflow. The portal was enlarged slightly to facilitate introduction of the cannula or the stapler directly into the knee. The nose of the stapler was applied to the superior surface of the inner edge of the meniscal tear. The sharp points on the tip of the nose were used to manipulate the inner edge and coapt the tear site. Firm pressure was applied to the meniscal tissue, and the nose of the stapler was embedded in the inner edge of the meniscus no more than 2 to 3 mm from the tear (as measured along the meniscal surface). The handle was pulled slowly as the staple engaged the meniscal tissue. This step was repeated every 3 to 4 mm to ensure ideal tear stabilization.

Cyclic testing of flexible all-inside meniscus suture anchors: biomechanical analysis

BACKGROUND

Flexible meniscus repair devices are designed to combine the benefits of rigid all-inside meniscus anchors with the biomechanical properties of sutures.

HYPOTHESIS

Stiffness and pull-out strength of flexible all-inside suture anchors and conventional sutures under cyclic loading conditions will be comparable.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 50 fresh frozen bovine menisci, artificial meniscus lesions were repaired with different meniscus fixation techniques: horizontal and vertical FasT-Fix, RapidLoc, and horizontal and vertical 2-0 Ethibond sutures. The specimens were cycled 1000 times between 5 and 20 N and then loaded to failure.

RESULTS

All devices survived the cyclic loading protocol. There was no significant difference in the displacement between all repair techniques tested (horizontal FasT-Fix, 6.23 mm; vertical FasT-Fix, 5.34 mm; RapidLoc, 6.84 mm; horizontal 2-0 Ethibond, 6.03 mm; vertical 2-0 Ethibond, 5.61 mm (P > .05). Vertical and horizontal FasT-Fix suture anchors had a significantly higher stiffness and pull-out strength (94.1 N and 80.8 N, respectively) than did horizontal sutures (50.2 N) and RapidLoc devices (30.3 N) (P > .05).

CONCLUSIONS

In this study, flexible all-inside meniscus anchors (FasT-Fix) had higher pull-out strength than did conventional vertical suture techniques. Biomechanical characteristics of the flexible RapidLoc are comparable to those of horizontal sutures.

CLINICAL RELEVANCE

Flexible all-inside meniscus repair devices are an alternative to conventional suture techniques.

A new rigid biodegradable anchor for meniscus refixation: biomechanical evaluation

All-inside repair devices have been developed to overcome the disadvantages of conventional suture techniques (such as vein and nerve damage and increased OR time). The Contour Meniscus Arrow is a second generation of the first biodegradable all-inside implant, the Meniscus Arrow. The aim of this study was to compare the biomechanical properties of the Contour Meniscus Arrow to the first-generation Meniscus Arrow and vertical or horizontal suture techniques. In fresh frozen bovine menisci, initial fixation strength, stiffness and failure mode of four different meniscus refixation techniques (Meniscus Arrow, Contour Meniscus Arrow, vertical and horizontal 2-0 Ethibond suture techniques) were evaluated in a computer-based material-testing machine at a rate of 12.5 mm/s. Vertical meniscus sutures showed the highest initial fixation strength, followed by the horizontal suture technique and the Contour Arrow. The Meniscus Arrow showed inferior pull-out strength. Subjecting the different refixation techniques to cyclic testing decreased the fixation strength in all groups. The modified Meniscus Anchor (Contour Arrow) provides biomechanical properties that are superior (pull-out strength) or similar (stiffness) compared to the first biodegradable all-inside implant, the Meniscus Arrow. The pull-out strength of the Contour Arrow was comparable to the pull-out strength reported for horizontal meniscus sutures in the literature. These biomechanical characteristics of this new implant justify clinical use.

Results of meniscal repair using a bioabsorbable screw

PURPOSE

With most all-inside arthroscopic meniscal repair devices, the surgeon has no need for additional incisions or arthroscopic knot tying, and surgical time is decreased compared with traditional suture repair. Although previous studies have examined the pullout strength of various all-inside devices, clinical data is lacking and has been presented for only a few implants. This study evaluates the clinical results of meniscal repair using a bioabsorbable screw.

TYPE OF STUDY

Retrospective case series.

METHODS

Twenty-five patients underwent 26 all-inside meniscal repairs using this device. Patient interviews were performed as was retrospective evaluation of patient records. Complications and repeat surgeries were noted.

RESULTS

The average age of the patients was 28.8 years (range, 15 to 44). The surgeries included 19 medial meniscus repairs and 7 lateral meniscus repairs; 12 patients underwent concomitant anterior cruciate ligament (ACL) reconstruction. We found 11 isolated meniscal repairs in stable knees and 2 isolated meniscal repairs in ACL-deficient knees. An average of 3.6 screws (range, 1 to 6) were used during the meniscal repairs. Eighteen of 25 patients were contacted at an average of 106 weeks (range, 70 to 189) postoperatively. The mean Tegner score was 5, and the mean modified Lysholm score was 84. Three repeat surgeries were performed for failure of meniscal healing, and one repeat surgery was performed for migration of an implant. An additional patient who underwent medial meniscal repair noted a painless mild prominence on the medial aspect of the knee approximately 8 weeks after surgery. This prominence resolved completely over 6 months and did not require a second surgery.

CONCLUSIONS

The bioabsorbable screw appears to be a safe and effective device for meniscal repair. Rare complications occurred that involved implant migration and transient inflammatory responses. Clinical success appears comparable to reported results with other methods of meniscal repair.

LEVEL OF EVIDENCE

Level IV, case series.

Initial fixation strength of flexible all-inside meniscus suture anchors in comparison to conventional suture technique and rigid anchors: biomechanical evaluation of new meniscus refixation systems

BACKGROUND

The newest generation of meniscus repair devices is designed to combine the benefits of the all-inside technique with the biomechanical properties of sutures.

HYPOTHESIS

New flexible all-inside suture anchors have better fixation strength than rigid anchors, but there is no difference when compared to conventional horizontal and vertical mattress sutures.

STUDY DESIGN

Controlled laboratory study.

METHODS

In fresh-frozen bovine menisci, initial fixation strength, stiffness, and failure mode of different meniscus fixation techniques (FastT-Fix, RapidLoc, Meniscus Arrow, horizontal and vertical 2.0 Ethibond sutures) were evaluated in a computer-based materials testing machine at a rate of 12.5 mm/sec.

RESULTS

The vertical and horizontal FastT-Fix suture anchors were the strongest devices with regard to pullout strength, with no significant difference compared to the vertical 2-0 Ethibond sutures. Horizontal sutures, Meniscus Arrow, and RapidLoc had significantly lower pullout strength. Vertical and horizontal FastT-Fix suture anchors showed significantly higher stiffness than the other devices.

CONCLUSIONS

Biomechanical properties of flexible all-inside meniscus anchors (FastT-Fix) are comparable to conventional vertical suture techniques. Characteristics of the flexible RapidLoc are comparable to rigid anchors (Meniscus Arrow).

CLINICAL RELEVANCE

From the biomechanical point of view, flexible all-inside meniscus refixation devices are an alternative to conventional suture techniques and rigid meniscus anchors.

"All-inside" meniscal repair devices: an experimental study in the goat model

BACKGROUND

Although the use of "all-inside" absorbable meniscal repair devices has become popular, numerous complications have been reported. The authors applied their well-established goat model to evaluate three "all-inside" meniscal repair devices.

METHODS

A "tear" was created in the medial meniscus of both knees in 26 goats. The animals were randomized into four groups, and the meniscus was treated as follows: (A) meniscal repair with Mitek Fastner, (B) meniscal repair with BioStinger, (C) meniscal repair with Mitek Clearfix Screw, and (D) no repair. All animals were sacrificed at 6 months postoperatively, and all specimens were carefully evaluated and results recorded and compared with historical results of meniscal repair with suture in this same animal model.

RESULTS

Meniscal repair results with all three all-inside devices studied were inferior to suture repair. Chondral injury was present in 75% to 100% of repairs with all-inside devices and none of the control specimens.

DISCUSSION

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CONCLUSION

Although new all-inside meniscal repair devices are relatively quick and easy, results may not be as good as with traditional suture techniques. The high rate of chondral injury associated with these devices in the goat model is worrisome for chondral damage in humans, especially in patients with smaller or tighter knees.

Meniscal repair devices: a clinical and biomechanical literature review

PURPOSE

The development of new approaches to arthroscopic meniscal repair has spurred the concomitant publication of studies reviewing their use and biomechanical properties. The purpose of this article is to review both the devices and the literature surrounding their clinical and biomechanical properties.

TYPE OF STUDY

Literature review.

METHODS

Studies were initially gathered using a MEDLINE search, and additional information was found through cross references. We evaluate a series of studies comparing sutures, suture anchors, screws, staples, and a variety of other devices in terms of initial fixation strength, degradation profile, performance under cyclical loading, and clinical success.

RESULTS

In the traditional suture studies, vertical sutures are clearly superior to both horizontal sutures and knot-end techniques in terms of initial fixation strength and performance under cyclical loading. Unfortunately, multidevice studies have been less consistent and less conclusive. the Linvatec Biostinger, Smith & Nephew T-fix, and Bionx Meniscus Arrow have separately been shown to have superior initial fixation strength on par with suture techniques. After cyclical loading, horizontal sutures, vertical sutures, 16-mm Arrows, 13-mm Arrows, and the Smith & Nephew T-fix generally show higher fixation strengths. Only the Bionx Arrow, Linvatec Biostinger, and Clearfix Screw have been shown to retain their initial fixation strengths through four months of hydrolysis time.

CONCLUSIONS

Data suggest that the biomechanical performance of some devices is nearly equivalent to current suture techniques. Ultimately, the combination of a simplified surgical technique, high clinical healing rates (75%-92%), and relatively minor complications makes these devices attractive for properly indicated meniscal tears.

Fixation strength of meniscal repair devices

The aim of this study was to measure and compare the ultimate failure strengths and cyclic fatigue strengths of currently available meniscal suturing devices. No statistically significant difference in failure load was found between a vertical loop suture (mean 46.3 N), a horizontal mattress suture (52.5 N), the T-fix Device (47.5 N), and the 16-mm (39.2 N) and 13-mm (32.8 N) Bionix Arrow. Statistically inferior results were seen with the 10-mm Bionix Arrow (18.8 N), the S.D. Sorb Stapler (4.3 N), and the 12-mm Arthrex Meniscal Dart (10.5 N) (P<0.01). The Mitek Meniscal Repair System (28.1 N) performed intermediate, with significantly better results than the S.D. Sorb Stapler and the 12-mm Arthrex Dart, but significantly worse than the vertical and horizontal sutures, the T-fix and Bionix 16-mm Device (P<0.01). Cyclic fatigue strength was significantly less for the 10-mm Bionix Arrow, the S.D. Sorb Stapler, and the 12-mm Arthrex Meniscal Dart (P<0.01) compared to all other devices. We conclude that the 13- and 16-mm Bionix Arrow and the T-fix Device have comparable ultimate failure strengths and cyclic fatigue strengths to conventional meniscal suturing techniques. The 10-mm Bionix Arrow, S.D. Sorb Stapler, and the 12-mm Arthrex Meniscal Dart, however, have far inferior failure and cyclic fatigue strengths and their clinical application should be questioned.

Comparison of the biomechanics and histology of two soft-tissue fixators composed of bioabsorbable copolymers

The purpose of this study was to assess the dynamic in vitro and in vivo characteristics of two different bioabsorbable copolymer soft-tissue fixation devices and to determine their efficacy in reattaching soft tissue to bone. Suretac fixators (Smith & Nephew/Acufex MicroSurgical Inc., Northwood, MA), made of polyglyconate (2:1 glycolic acid:trimethylene carbonate), and Pop Rivets (Arthrotek, Warsaw, IN), made of LactoSorb (82% poly L-lactic acid, 18% polyglycolic acid), were anchored into synthetic bone, and their pull-out strengths were evaluated. The devices were also evaluated with the use of an in vivo goat model in which the medial collateral ligament (MCL) was elevated from the tibia and directly reattached. In the in vitro biomechanical study, the Suretac fixators had negligible strength remaining by four weeks, whereas the Pop Rivets retained 50% of their strength at 4 weeks, 20% at 8 weeks, and negligible strength at 12 weeks. The in vivo strength of MCL repairs affected by each implant was not statistically different at any of the time points. Histologically, both implants were absorbed by 52 weeks, and there was no appreciable adverse tissue response. In conclusion, both copolymer fixators were found to be biocompatible. The Pop Rivet fixators demonstrated in vivo performance comparable to the Suretac fixators, although the Pop Rivets retained strength longer in vitro. Our results suggest that both devices provide adequate strength of fixation before degrading to allow the healing soft tissues to reach or surpass their native strength.

Failure strengths of suture vs. biodegradable arrow and staple for meniscal repair: an in vitro study

A study was performed to determine the in vitro biomechanical behaviour of two 'all inside' meniscal repair techniques (Meniscal Arrow [Bionx Implants Inc.] and Meniscal Staple [Surgical Dynamics Inc.]) and compare these directly with both a horizontal and vertical suture repair. Using 30 fresh bovine medial menisci, vertical 'bucket handle' tears were created 4 mm from the meniscus periphery. Repairs were subsequently performed, using four techniques, with 15 repairs in each group, a horizontally placed 3-metric Ethibond suture, a vertically placed 3-metric Ethibond suture, a single 13-mm arrow and a single 7-mm staple. A tensile test was performed to determine the force at failure for each technique. The mean force at failure of the horizontal and vertical suture groups was 63.2 and 73.9 N, respectively, 44.3 N for the arrow group and 17.8 N for the staple group. The mean forces at failure were significantly different (P < 0.005). The mean tensile strength of the meniscal staple was significantly lower than that of both suture and arrow groups. The 7-mm staple design may not allow adequate interdigitation between the barbed legs and the semicircular collagen fibres of the meniscus.

Pre-clinical in vivo evaluation of orthopaedic bioabsorbable devices

The presence of bioabsorbable materials in orthopaedics has grown significantly over the past two decades with applications in fracture fixation, bone replacement, cartilage repair, meniscal repair, fixation of ligaments, and drug delivery. Numerous biocompatible, biodegradable polymers are now available for both experimental and clinical use. Not surprisingly, there have been a wealth of studies investigating the biomechanical properties, biocompatibility, degradation characteristics, osteoconductivity, potential toxicity, and histologic effects of various materials. Promising results have been reported in the areas of fracture fixation, ligament repair, and drug delivery. In this article we review the pre-clinical in vivo testing of bioabsorbable devices with particular emphasis on implants used for these applications.

Biofix arrow appearing as a subcutaneous foreign body

SUMMARY

Recent progress in meniscal repair technology has included the development of bioabsorbable implants that can be inserted without a posterior incision. Satisfactory success rates have been reported. Reports of complications have been rare. We present 5 cases of failure of a biodegradable meniscal repair implant, each of which presented as a subcutaneous foreign body.

Principles of development and use of absorbable internal fixation

Absorbable internal fixation implants, by virtue of their temporary in situ residence and variable load sharing with the healing tissues, have the potential to yield a clinical outcome that approaches the native state. Despite the growing availability and acceptance of absorbable fixation, however, many surgeons continue to rely upon metal fixation for their patients, due, in part, to unfamiliarity with the technology. Although many of the principles of metallic internal fixation also apply to absorbable internal fixation, significant differences exist as well. This paper presents basic background in absorbable technology and proposes a set of principles that may help govern the development and use of absorbable fixation devices in clinical practice.

Cyclic testing of meniscal sutures

Suturing the meniscus has become a standard procedure for repairable tears. Studies investigating the outcome of meniscal sutures report a considerable rate of failures. Regarding the indications, which have been extended to the avascular zones, and regarding some accelerated rehabilitation protocols, the need for further in vitro investigations has become obvious. The aim of this study was to compare different meniscal suture types (vertical and horizontal mattress sutures) and materials (absorbable monofilament PDS 2-0, and nonabsorbable braided Ethibond 2-0 [Ethicon, Somerville, NJ]) under standard and cyclic loading conditions. Testing was performed on medial porcine menisci. In group A, specimens were tested to failure at a cross-head speed of 50 mm/minute. In group B, cyclic testing (100 cycles) was performed first within different load intervals (5 to 20 N and 5 to 40 N). Finally, the specimens were loaded until failure. In both groups, the failure loads were recorded and the failure modes were analyzed. In group A, there was no difference between suture type or suture material, with a mean failure load of 60 N. The failure modes were significantly different for vertical (100% suture failure) and horizontal sutures (50% suture failure) (P <.0001). In group B, 13% of the sutures failed under cyclic loading (7 with 40-N load, 1 with 20-N load). The gap of the sutured tear that appeared within the first load cycles was broader in horizontal sutures (P <.001). During the first cycles, the thread cut through the meniscus tissue and disappeared from the surface (partial tissue failure). There was no difference according to suture material. The ultimate failure loads after cyclic loading did not differ from the values of group A. These results show that meniscal sutures may fail under repetitive loading conditions and that a gap appears between the meniscal margins within the first loading cycles irrespective of the suture type and suture material used. The appearance of the gap and suture disappearance on the meniscal surface because of partial tissue failures (which were more pronounced in the horizontal sutures) confirmed the superior resistance of meniscal tissue to vertical sutures.

Treatment of partial meniscal tears identified during anterior cruciate ligament reconstruction with limited synovial abrasion

SUMMARY

This is a retrospective review of the results of 40 patients with 44 partial stable meniscal tears who were treated with parameniscal synovial abrasion at the time of anterior cruciate ligament reconstruction. There were 19 medial meniscal (MM) tears and 25 lateral meniscal (LM) tears. Meniscal tear morphology included 33 single longitudinal tears (18 MM, 15 LM), 10 double longitudinal tears (1 MM, 9 LM), and 1 radial tear (LM). All 44 tears were located in the posterior horn or posterior junction of the meniscus. Rim width was </=3 mm in 29 and >3 mm in 15 tears. In this study, failure was defined as a symptomatic meniscal tear requiring subsequent surgery. The overall failure rate at an average follow-up of 3.3 years was 11% (5 of 44). Four failures occurred in the MM (21% of total MM tears) and 1 failure occurred in the LM (4% of total LM tears). The median time to failure was 12 months with 3 of 5 failures occurring secondary to a significant reinjury. We looked at the effect of 8 factors on overall failure rate. Although statistical validity was not established in this small patient population, we did observe a higher failure rate for stable MM tears. Our study supports the small amount of literature that shows a high clinical success rate with observation of stable LM tears identified at the time of anterior cruciate ligament reconstruction. However, the much higher failure rate of stable MM tears raises concern. This difference is explained by biomechanical and clinical studies showing that the MM develops higher stresses than the LM with loading. Based on this work, we believe that stable longitudinal MM tears have a higher propensity to fail over time by propagation of the tear and are better managed with meniscal repair.