Biomechanical Testing of Suture-Based Meniscal Repair Devices Containing Ultrahigh-Molecular-Weight Polyethylene Suture: Update 2011

Biomechanical Testing of Suture-Based Meniscal Repair Devices Containing Ultrahigh-Molecular-Weight Polyethylene Suture: Update 2011 F. Alan Barber, M.D., Morley A. Herbert, Ph.D., Eric D. Bava, M.D., and Otis R. Drew, M.D.

Purpose: To evaluate the biomechanical characteristics of recently introduced ultrahigh-molecularweight polyethylene suture– based, self-adjusting meniscal repair devices. Methods: Updating a prior study published in 2009, we made vertical longitudinal cuts 3 mm from the periphery in fresh-frozen adult human menisci to simulate a bucket-handle meniscus tear. Each tear was then repaired by a single repair technique in 10 meniscus specimens. Group 1 menisci were repaired with a vertical mattress suture of No. 2-0 Ethibond (Ethicon, Somerville, NJ). Group 2 menisci were repaired with a vertical mattress suture of No. 2-0 OrthoCord (DePuy Mitek, Raynham, MA). Group 3 menisci were repaired with a single OmniSpan device with No. 2-0 OrthoCord suture (DePuy Mitek). Group 4 menisci were repaired with a single Meniscal Cinch device with No. 2-0 FiberWire suture (Arthrex, Naples, FL). Group 5 menisci were repaired with a single MaxFire device inserted with the MarXmen gun (Biomet Sports Medicine, Warsaw, IN). Group 6 menisci were repaired with a Sequent device with No. 0 Hi-Fi suture (ConMed Linvatec, Largo, FL) in a “V” suture configuration. Group 7 menisci were repaired with a single FasT-Fix 360 device (Smith & Nephew Endoscopy, Andover, MA). By use of a mechanical testing machine, all samples were preloaded at 5 N and cycled 200 times between 5 and 50 N. Those specimens that survived were destructively tested at 5 mm/min. Endpoints included maximum load, displacement, stiffness, and failure mode. Results: Mean failure loads were as follows: Ethibond suture, 73 N; OrthoCord suture, 88 N; OmniSpan, 88 N; Cinch, 71 N; MarXmen/MaxFire, 54 N; Sequent, 66 N; and FasT-Fix 360, 60 N. Ethibond was stronger than MarXmen/MaxFire. The mean displacement after 100 cycles was as follows: Ethibond, 2.58 mm; OrthoCord, 2.75 mm; OmniSpan, 2.51 mm; Cinch, 2.65 mm; MarXmen/MaxFire, 3.67 mm; Sequent, 3.35 mm; and FasT-Fix 360, 1.13 mm. The MarXmen/MaxFire showed greater 100-cycle displacement than Ethibond and FasT-Fix 360. No difference in stiffness existed for these devices, and failure mode varied without specific trends. Conclusions: The biomechanical properties of meniscal repairs using the OmniSpan, Cinch, Sequent, and FasT-Fix 360 devices are equivalent to suture repair techniques. However, the MarXmen/MaxFire meniscal repair device showed significantly lower failure loads and survived less cyclic loading in the human cadaveric meniscus than other tested repairs. Clinical Relevance: Most commercially available devices for all-inside meniscal repair using ultrahigh-molecular-weight polyethylene suture provide fixation comparable to the classic vertical mattress suture repair technique in human cadaveric meniscus.

From the Plano Orthopedic Sports Medicine and Spine Center (F.A.B., E.D.B., O.R.D.), Plano, Texas; and Advanced Surgical Institutes, Medical City Dallas Hospital (M.A.H.), Dallas, Texas, U.S.A. The authors report the following potential conflict of interest or source of funding in relation to this article: The meniscus repair devices tested were provided at no cost by the various companies making them. In addition, a $500 fee to underwrite the costs of the Instron machine was paid. Received April 26, 2011; accepted November 17, 2011. Address correspondence to F. Alan Barber, M.D., Plano Orthopedic Sports Medicine and Spine Center, 5228 W Plano Pkwy, Plano, TX 75093, U.S.A. © 2012 by the Arthroscopy Association of North America 0749-8063/11263/$36.00 doi:10.1016/j.arthro.2011.11.020

Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 28, No 6 (June), 2012: pp 827-834

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eniscus repair can be accomplished by a variety of surgical techniques. The inside-out suture repair using a braided polyester suture has become a well-established and accepted technique for the treatment of reparable meniscal tears.1-6 However, technical difficulty exists with suture repairs of posterior horn meniscal tears, and the strength of No. 2-0 braided polyester suture makes it subject to breaking. Newer meniscal repair devices now allow for repair of the meniscus by all-inside techniques. The initial generation of all-inside rigid fixation devices (i.e., tacks, staples, and screws) has been shown to provide lower load-to-failure strength and carry the risk of chondral abrasion because a portion of these devices remain exposed on the meniscal surface.7-10 The development of all-inside meniscal repair devices with “self-adjusting” sutures provided greater strength and safety, but the braided polyester suture material was still subject to breaking.7,10,11 The current generation of self-adjusting suture devices made with ultrahigh-molecular-weight polyethylene (UHMWPE) material may provide a stronger allarthroscopic technique that is less likely to break, avoids the need for additional incisions about the knee, decreases the potential for injury to the neurovascular structures about the knee,12-18 and avoids many of the complications linked to the prior meniscal repair techniques.7-10 Previous testing of these self-adjusting UHMWPE suture devices in a porcine meniscus model has shown promising biomechanical data.19 However, it is unclear how these devices perform in human meniscus tissue. In addition, prior studies using a single destructive pull for testing do not replicate the clinical condition as well as cyclic loading followed by destructive testing. The purpose of this study was to evaluate the biomechanical characteristics of recently introduced UHMWPE suture– based, selfadjusting meniscal repair devices in a human cadaveric model. The hypothesis of this study was that the different UHMWPE suture– containing devices would show better structural properties when subjected to cyclic loading in the human meniscus model.

vertical longitudinal cut 3 mm from the periphery of each meniscus was created with a knife. This cut was created after the meniscus was completely removed from the tibia. The cut was not initially extended into the anterior and posterior meniscal horns to allow better control of the test meniscus during repair device insertion. A single suture or repair device was placed in each meniscus to approximate the 2 meniscal edges. All meniscal repair sutures or devices were placed in the posterior horn, and both medial and lateral menisci from the same knee were used with each device. Once the repair construct was placed and the repair complete, we divided the 2 remaining tissue bridges, completely separating the meniscus into 2 segments connected only by the single repair. Testing was conducted on a 3345 Instron mechanical testing machine (Instron, Canton, MA) and cyclically loaded at a displacement rate of 5 mm/min19-21 with a distraction stress always parallel to the axis of the repair device being tested (Fig 1). Each segment of the repaired meniscus was held with 2 metal clamps that were in turn attached to the mechanical testing

METHODS We used 70 fresh-frozen adult human menisci (from 35 knees) provided by the Musculoskeletal Transplant Foundation (Edison, NJ) for research purposes. The meniscus specimens used in this bench test were all free meniscus specimens suitable for use as meniscal allografts. All menisci were intact and unblemished. A

FIGURE 1. Testing was conducted on a mechanical testing machine with each meniscal segment held with 2 metal clamps. © F. Alan Barber.

MENISCAL REPAIR DEVICES

FIGURE 2. A single vertical suture of No. 2-0 Ethibond was placed 3 mm inside the meniscal cut and hand tied on the capsular side of the meniscus to approximate the 2 meniscal fragments. © F. Alan Barber.

machine. This allowed the consistent application of force to the repair system without the plastic deformation associated with suture or tape materials. After an initial preload to take the slack out of the system, a cyclic loading force between 5 and 50 N was applied at 1 Hz for 200 cycles. Those specimens that survived the cycling were destructively tested (loaded to failure) at a rate of 5 mm/min.19-21 Load and displacement were sampled continuously at 10 Hz. The displacement was measured by the travel of the actuator of the materials testing machine. This loading rate simulates the stresses on the meniscus during early postoperative rehabilitation exercises and activities of daily living, such as slow-speed walking, stair climbing or descending, and squatting. This testing protocol was consistent with previously published testing protocols.7,10,19,20,22 A total of 10 samples for each repair device tested were used. The sampling rate for force and position data was 50 per second. This was downloaded into a spreadsheet and analyzed with statistical software. Endpoints for this testing were as follows: 1. Maximum load to failure with destructive testing after 200 cycles 2. Cyclic displacement at both 100 cycles and 200 cycles 3. Stiffness, determined from the maximal endpoints of the linear region of the load-displacement plot 4. Mode of failure, determined by visual inspection of the failure result

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The repair devices tested included the following: In group 1 a single vertical suture of No. 2-0 Ethibond (Ethicon, Somerville, NJ) was placed 3 mm inside the meniscal cut, extending from the superior surface to the inferior surface of the meniscus, and tied by hand with 6 square knots on the capsular side of the meniscus, approximating the 2 fragments of meniscus (inside-out vertical stitch). This served as the “classic” control device repair to provide comparison to the historical record (Fig 2). In group 2 a single vertical suture of No. 2-0 OrthoCord (DePuy Mitek, Raynham, MA) (55% polydioxanone and 45% UHMWPE) was placed 3 mm inside the meniscal cut, extending from the superior surface to the inferior surface of the meniscus, and tied by hand with 6 square knots on the capsular side of the meniscus, approximating the 2 fragments of meniscus (high-strength suture inside-out vertical stitch control). In group 3 a repair using the OmniSpan device (DePuy Mitek) (Fig 3) was placed in a vertical mattress configuration on the superior surface of the meniscus, 3 mm inside the meniscal cut and angled to orient 1 arm toward the superior peripheral capsule and the second toward the inferior meniscal capsule. The OmniSpan has a strand of No. 2-0 OrthoCord that is doubled between 2 poly ether ether ketone (PEEK) anchors, inserted by a gun with a curved needle. The sliding locking knot is located on the outside of the first PEEK anchor inserted and creates a repair with 2 sutures crossing between the 2 anchors without a knot on the meniscal surface.

FIGURE 3. The OmniSpan has a strand of No. 2-0 OrthoCord that is doubled between 2 PEEK anchors. The sliding locking knot is located on the outside of the first PEEK anchor and creates a repair with 2 sutures crossing between the 2 anchors without a knot on the meniscal surface. © F. Alan Barber.

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FIGURE 4. The Meniscal Cinch has 2 PEEK anchors connected by No. 0 FiberWire with a pre-tied sliding locking knot. © F. Alan Barber.

In group 4 a repair using the Meniscal Cinch (Arthrex, Naples, FL) (Fig 4) was placed in a vertical mattress configuration by use of a dual-needle insertion gun on the superior surface of the meniscus, 3 mm inside the meniscal cut and angled to orient 1 arm toward the superior peripheral capsule and the second toward the inferior meniscal capsule. This anchor has 2 PEEK anchors connected by No. 0 FiberWire (braided polyester and UHMWPE) (Arthrex) with a pre-tied sliding locking knot. In group 5 a repair using the MarXmen gun to insert the MaxFire repair device (Biomet Sports Medicine, Warsaw, IN) (Fig 5) was placed 3 mm inside the meniscal cut, creating a vertical repair. The MaxFire

FIGURE 5. The MaxFire device (inserted by the MarXmen gun) is made from MaxBraid suture with 2 soft anchors consisting of polyethylene sleeves that bunch up to create anchors for stitch security. © F. Alan Barber.

FIGURE 6. The Sequent meniscal repair device has up to 7 PEEK anchors connected with No. 0 Hi-Fi suture and allows a continuous stitching technique. The stitch is secured at each PEEK anchor by making 2 full clockwise rotations of the insertion device and tensioning the suture to lock it into the PEEK anchor’s slots. © F. Alan Barber.

device is made from MaxBraid suture (Biomet Sports Medicine) with 2 anchors consisting of polyethylene sleeves. After deploying, these sleeves bunch up to create anchors for stitch security. A pre-tied sliding locking knot is part of the repair. In group 6 a repair using the Linvatec Sequent meniscal repair device (ConMed Linvatec, Largo, FL) (Fig 6) was inserted, by use of the associated insertion device, starting at the periphery of the cut and then moving 3 mm inside the meniscal cut and back to the periphery again to create a “V”-shaped vertical repair. This repair device allows for a continuous stitching technique and comes with up to 7 PEEK anchors. Three of these anchors were used to create this Vshaped repair. These anchors are connected by No. 0 Hi-Fi (UHMWPE) suture (ConMed Linvatec), and the knots are created at each subsequent anchor by making 2 full clockwise rotations of the insertion device and tensioning the suture to lock it into the slots of the PEEK anchor. In group 7 a repair using the FasT-Fix 360 device (Smith & Nephew Endoscopy, Andover, MA) (Fig 7) was placed by use of a curved-needle insertion device in a vertical mattress configuration on the superior surface of the meniscus, 3 mm inside the meniscal cut and angled to orient 1 arm toward the superior peripheral capsule and the second toward the inferior meniscal capsule. This anchor also has 2 reconfigured PEEK anchors connected by No. 2-0 UltraBraid (UHMWPE) (Smith & Nephew Endoscopy) with a sliding locking knot. In contrast, the prior version of this device (Ultra FasT-Fix) contained a larger No. 0 UHMWPE suture. In addition, the PEEK anchors of this version are arrow shaped.

MENISCAL REPAIR DEVICES TABLE 2.

831 Failure Loads of Devices Completing 200 Cycles Force (N)

Device

n

Mean

SD

Minimum

Maximum

Ethibond OrthoCord OmniSpan Cinch MarXmen/MaxFire Sequent FasT-Fix 360

7 8 6 7 1 6 3

80.7 100.5 112.2 85.3 105.2 74.2 81.2

6.13 17.23 39.31 17.81 — 16.60 11.5

74 72.2 93.2 61.1 105.2 53.8 67.9

90.5 123.8 178.4 108.5 105.2 99.8 87.9

NOTE. The MarXmen/MaxFire completed fewer cycles than the other devices except for FasT-Fix 360 (P ⬍ .05).

FIGURE 7. The FasT-Fix 360 device has 2 arrow-shaped PEEK anchors connected by No. 2-0 UltraBraid with a sliding locking knot. © F. Alan Barber.

Statistical Analysis A general linear model was used to perform an analysis of variance for the data. If the data indicated statistical significance, Duncan multiple range tests were performed. Statistical significance was placed at P ⬍ .05. RESULTS Mean load-to-failure data of the tested all-inside meniscal repairs (devices and sutures) are shown in Table 1. When compared with the Ethibond suture repair, the OrthoCord suture, OmniSpan, Cinch, Sequent, and FasT-Fix 360 repairs did not exhibit a TABLE 1.

statistically significant difference. However, the Ethibond suture repair was superior to MarXmen/MaxFire with regard to load to failure (P ⫽ .03). Because not all devices tested completed all 200 cycles, the mean number of cycles completed varied for the different devices: Ethibond suture, 140 cycles; OrthoCord suture, 160 cycles; OmniSpan, 121 cycles; Cinch, 140 cycles; MarXmen/MaxFire, 37 cycles; Sequent, 110 cycles, and FasT-Fix 360, 66 cycles. The MarXmen/MaxFire device completed statistically fewer cycles than the other devices except for FasT-Fix 360 (P ⬍ .05). Considering only those tests that completed the full 200 cycles of testing, we generated load-to-failure data (Table 2). The MarXmen/MaxFire data should not be compared with the other devices because only 1 sample completed the cyclic loading. The amount of cyclic displacement at 100 cycles and 200 cycles was the second endpoint studied (Table 3).

TABLE 3.

Cyclic Displacement After 100 Cycles and 200 Cycles

Load-to-Failure Data

Cyclic Displacement (mm)

Force (N) Device

n

Mean

SD

Minimum

Maximum

Ethibond OrthoCord OmniSpan Cinch MarXmen/MaxFire Sequent FasT-Fix 360

10 10 10 10 10 10 10

73.3 87.7 87.6 70.9 54.3 66.3 60.5

13.08 31.06 54.71 27.53 20.47 19.87 15.8

53.0 32.8 8.61 32.7 30.8 40.3 41.0

90.5 123.8 178.43 108.5 105.2 99.8 87.9

NOTE. The mean failure load of the Ethibond suture repair was superior to that of the MarXmen/MaxFire repair (P ⫽ .03).

Device

100 Cycles

200 Cycles

Ethibond OrthoCord OmniSpan Cinch MarXmen/MaxFire Sequent FasT-Fix 360

2.58 2.75 2.51 2.65 3.67 3.35 1.13

3.12 3.36 3.09 3.15 4.35 3.62 1.42

NOTE. The MarXmen/MaxFire device showed more displacement at 100 cycles than the Ethibond suture and FasT-Fix 360 (P ⬍ .05). The FasT-Fix 360 device showed less displacement at 200 cycles than the other repairs (P ⬍ .05).

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Stiffness

Device

Stiffness (N/mm)*

Ethibond OrthoCord OmniSpan Cinch MarXmen/MaxFire Sequent FasT-Fix 360

26.5 27.0 27.45 28.6 27.0 31.7 34.7

*P ⫽ .58.

The MarXmen/MaxFire device showed statistically more displacement at 100 cycles than Ethibond suture and FasT-Fix 360 (P ⬍ .05). The increase in displacement was less between 100 cycles and 200 cycles than for the first 100 cycles. The FasT-Fix 360 device showed statistically less displacement at 200 cycles than the other repairs (P ⬍ .05). The third endpoint studied was stiffness. There was no statistical difference among the repair devices for stiffness (Table 4). The mode of failure during the cyclic testing was recorded. The specific modes of failure are listed in Table 5. DISCUSSION The development of all-inside meniscal repair devices with UHMWPE suture is a significant advance in the repair of meniscus tears. UHMWPE suture is significantly stronger than braided polyester suture.19,25 The mechanical properties of these self-adjusting UHMWPE suture repair devices were reported in a porcine meniscus model.19 The porcine meniscus model has been observed to show results similar to that of a young adult human meniscus with more consistent mechanical properties than those found in an older human cadaveric meniscus.2 Our hypothesis was not supported by these data. The different UHMWPE suture– containing devices did not show better structural properties with cyclic loading in the human meniscus model than previously reported. Several factors contributed to this. A comparison of this human cadaveric study to the porcine model data illustrates the inconsistency of the human cadaveric model. The strength and consistency of the young porcine tissue resulted in the suture (usually UHMWPE) breaking in 82% of the tests,19 whereas in this study only 41% of the tests resulted in suture breaking. In contrast, the loads at failure are very similar when the porcine model data are compared

with the human cadaveric model data. The bovine meniscus model also shows better consistency than the human model; however, its greater density results in higher failure loads than in the human model.26 Performing the current study in human cadaveric meniscus allows for this comparison to the historical data for other biologic materials. The human cadaveric meniscus tissue was often the weakest point of the repair, as evidenced by the numerous specimens that failed by the suture cutting through the meniscus, the clamps pulling through the meniscus, or even the device anchors pulling through the meniscus. A comparison of the performance of the human meniscus in this test to that of porcine and bovine tests supports the conclusion that the human meniscus is not the best model for comparison testing of these devices. The younger porcine model is more consistent and provides a more reliable testing environment. The testing mechanism in this study was cyclic distraction followed by destructive loading. During the postoperative rehabilitation and healing phase, a meniscal repair is subjected to compression and shear loads but probably less distraction.27-29 In addition, these loads can be under 10 N.29 Previous studies have shown that distraction loads are not significant across the repair site.27,28,30 Whereas 1 biomechanical study reported significantly higher shear failure loads than distraction failure loads for a suture-based device, in that study the reverse was true for braided polyester suture repairs.31 No statistical difference between distraction and shear failure loads was shown for an earlier-generation rigid meniscal fixation device.31 Other studies comparing distraction load testing and shear load testing have failed to show any significant difference between shear and distraction test modes for the meniscal repair devices tested.32,33 It is thereTABLE 5.

Failure Modes for Devices Tested

Device

Device Pulled Out

Suture Broke

Suture Pull Through

Clamp Failure

Ethibond OrthoCord OmniSpan Cinch MarXmen/MaxFire Sequent FasT-Fix 360

— 1 1 6 4 4 1

10 3 5 4 6 — 1

— 4 2 — — 6 8

— 2 2 — — — —

NOTE. The Ethibond sutures consistently broke away from the knot. On the basis of prior studies,23,24 slippage seldom occurs with Ethibond. OrthoCord pulled out of the meniscus with the suture and knot intact. This is an example of why the human meniscus has some limitations as a study model.

MENISCAL REPAIR DEVICES fore reasonable to conclude at this point, in the absence of a better model, that it is valid to test meniscal repair device performance by destructive distraction after cyclic loading. Early designs using rigid meniscal repair devices did not provide repair strength comparable to that of a single braided polyester suture.7,9,10,25 These early designs were typically rigid devices, which often left part of the device on the meniscal surface and were associated with reports of articular cartilage damage and device migration.34-36 Testing comparing these earlier designs with suture-based devices showed, in addition to statistically lower failure loads, device breakage and migration as part of the failure mode.32 Our study shows that the OmniSpan, Cinch, Sequent, and FasT-Fix 360 meniscal repair devices, all of which use UHMWPE-containing suture, provide repair strengths that are comparable to an inside-out repair performed with a braided polyester suture (Ethibond) or a UHMWPE-containing suture (OrthoCord). However, the MarXmen/MaxFire meniscal repair showed significantly lower mean failure loads, completed fewer load cycles, and had significantly greater displacement during the first 100 cycles of loading when compared with the inside-out repair using braided polyester suture. This lower failure strength and increased failure occurrence during cyclic loading of the MarXmen/ MaxFire device have been previously observed.37 One possible reason for these results may be the device design. All of the other device designs (OmniSpan, Cinch, Sequent, and FasT-Fix 360) incorporate rigid PEEK capsular anchors. In contrast, the MaxFire is an all-suture device that does not use a rigid capsular anchor, which may affect its biomechanical properties in the human cadaveric meniscus. Even though the current data do not necessarily show an ultimate strength benefit with the UHMWPE suture– containing devices, there are clear benefits with these devices that are responsible for their overwhelming clinical popularity. These self-adjusting suture devices allow an all-inside technique and are arguably easier to use than inside-out sutures. Secondary incisions associated with the inside-out technique are not required, and perhaps most importantly, the No. 2-0 braided polyester inside-out sutures were subject to frequent breaking during handling and knot tying whereas the UHMWPE sutures of comparable size are not. Various modes of failure were found for the selfadjusting repair devices, whereas Ethibond failed exclusively by suture breaking. Because of the distribution of failure modes and the limited number of

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specimens tested, no conclusion can be drawn from these data. The human cadaveric meniscus tissue used performed with greater variability than porcine meniscus used previously. Consequently, no device had all of its specimens survive 200 cycles. One weakness of this study is that the test protocol does not exactly re-create the mechanism by which a meniscal repair fails. The repairs were subjected to distractive forces, not compressive axially applied rotational loads or shear forces, during testing. Testing was carried out at room temperature and not in an isotonic aqueous environment. This was a time 0 test, which also decreases any impact of hydrolysis on the material over time. Precisely how much force is required to hold a repaired meniscus together during loaded knee flexion and extension is currently not established, and the data generated are only 1 aspect of repair device performance, which may not directly correlate with clinical healing. Consequently, any of these repair devices may be clinically appropriate. The values generated in this study cannot provide a direct application to performance in the clinical model, and there are no data generated on the potential for clinical healing or the potential for complications. The number of samples tested was limited by the availability of human menisci. Consequently, the finding that no difference existed for some comparisons does not mean that a difference did not exist (␤ error). Finally, a comparison of these data to the historical biologic alternatives suggests that a human cadaveric meniscus may not be the best biologic model for this testing. CONCLUSIONS The biomechanical properties of meniscal repairs using the OmniSpan, Cinch, Sequent, and FasT-Fix 360 devices are equivalent to suture repair techniques. However, the MarXmen/MaxFire meniscal repair device showed significantly lower failure loads and survived less cyclic loading in the human cadaveric meniscus than other tested repairs. Acknowledgment: The authors appreciate the assistance of Jennifer Heldreth in this research.

REFERENCES 1. Morgan CD. The “all-inside” meniscus repair. Arthroscopy 1991;7:120-125. 2. Post WR, Akers SR, Kish V. Load to failure of common meniscal repair techniques: Effects of suture technique and suture material. Arthroscopy 1997;13:731-736.

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3. Rimmer MG, Nawana NS, Keene GC, Pearcy MJ. Failure strengths of different meniscal suturing techniques. Arthroscopy 1995;11:146-150. 4. Maruyama M. The all-inside meniscal suture technique using new instruments. Arthroscopy 1996;12:256-258. 5. Feng H, Hong L, Geng XS, Zhang H, Wang XS, Jiang XY. Second-look arthroscopic evaluation of bucket-handle meniscus tear repairs with anterior cruciate ligament reconstruction: 67 consecutive cases. Arthroscopy 2008;24:1358-1366. 6. Espejo-Baena A, Figueroa-Mata A, Serrano-Fernandez J, et al. All-inside suture technique using anterior portals in posterior horn tears of lateral meniscus. Arthroscopy 2008;24:369.e1369.e4. Available online at www.arthroscopyjournal.org. 7. Barber FA, Herbert MA. Meniscal repair devices. Arthroscopy 2000;16:613-618. 8. Naqui SZ, Thiryayi WA, Hopgood P, Ryan WG. A biomechanical comparison of the Mitek RapidLoc, Mitek Meniscal repair system, Clearfix screws and vertical PDS and Ti-Cron sutures. Knee 2006;13:151-157. 9. Becker R, Starke C, Heymann M, et al. Biomechanical properties under cyclic loading of seven meniscus repair techniques. Clin Orthop Relat Res 2002:236-245. 10. Barber FA, Herbert MA, Richards DP. Load to failure testing of new meniscal repair devices. Arthroscopy 2004;20:45-50. 11. Zantop T, Eggers AK, Weimann A, Hassenpflug J, Petersen W. 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. Am J Sports Med 2004;32:863-869. 12. Albrecht-Olsen P, Lind T, Kristensen G, Falkenberg B. Failure strength of a new meniscus arrow repair technique: Biomechanical comparison with horizontal suture. Arthroscopy 1997; 13:183-187. 13. Barber FA, Coons DA. Midterm results of meniscal repair using the BioStinger meniscal repair device. Arthroscopy 2006;22:400-405. 14. Barber FA, Coons DA, Ruiz-Suarez M. Meniscal repair with the RapidLoc meniscal repair device. Arthroscopy 2006;22: 962-966. 15. Haas AL, Schepsis AA, Hornstein J, Edgar CM. Meniscal repair using the FasT-Fix all-inside meniscal repair device. Arthroscopy 2005;21:167-175. 16. Siebold R, Dehler C, Boes L, Ellermann A. Arthroscopic all-inside repair using the Meniscus Arrow: Long-term clinical follow-up of 113 patients. Arthroscopy 2007;23:394-399. 17. Barber FA, Schroeder FA, Oro FB, Beavis RC. FasT-Fix meniscal repair: Mid-term results. Arthroscopy 2008;24:13421348. 18. Kalliakmanis A, Zourntos S, Bousgas D, Nikolaou P. Comparison of arthroscopic meniscal repair results using 3 different meniscal repair devices in anterior cruciate ligament reconstruction patients. Arthroscopy 2008;24:810-816. 19. Barber FA, Herbert MA, Schroeder FA, Aziz-Jacobo J, Sutker MJ. Biomechanical testing of new meniscal repair techniques containing ultra high-molecular weight polyethylene suture. Arthroscopy 2009;25:959-967. 20. Chang HC, Nyland J, Caborn DN, Burden R. Biomechanical evaluation of meniscal repair systems: A comparison of the Meniscal Viper Repair System, the vertical mattress FasT-Fix

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