Skip to main content

Placement of sutures for inside-out meniscal repair: both sutures through meniscal tissue reduces displacement on cyclical loading

Abstract

Purpose

The inside-out meniscal repair is widely performed to preserve the function of meniscus. In this technique, the outer suture is passed through the capsule as well as the outer meniscus, while the inner suture is inserted into the meniscus. The aim of this study was to biomechanically compare the suture stability between meniscus-meniscus and meniscus-capsule suture methods for the longitudinal meniscal tear with inside-out technique.

Methods

Twenty-seven porcine knees were dissected to maintain the femur-medial capsule/meniscus-tibia complex, and the inner meniscus was cut off along the meniscus circumferential fiber with 3 mm width of the peripheral meniscus preserved. After one needle with a 2-0 polyester suture was inserted into the inner portion of the meniscus, the other needle was inserted through 1) the peripheral meniscus (Group A), 2) capsule just above the meniscus (Group B), and 3) capsule at 10 mm apart from the meniscus-capsule junction (Group C) in the inside-out manner. Then, the suture was manually tied on the capsule. The suture gap at the repair site during 300 times of cyclic loading and the ultimate failure load in the load-to-failure test were measured. The statistical significance of the data between two groups in each combination was considered by Bonferroni correction, following a one-way analysis of variance.

Results

In the cyclic loading test, the suture gap was 0.68 ± 0.26 mm in Group A, 1.08 ± 0.36 mm in Group B, and 1.94 ± 0.57 mm in Group C with a significant difference. In the load-to-failure test, the ultimate failure load was 59.1 ± 13.6 N in Group A, 60.0 ± 7.9 N in Group B, and 57.4 ± 4.7 N in Group C, and there was no significant difference.

Conclusion

The stitching region in the inside-out technique for longitudinal meniscal tear affected the stability of the tear site, and stitching the mid-substance region of the meniscus provides good stability in response to cyclic tensile loading. In addition, the stitching region did not affect the ultimate failure load.

Clinical relevance

In the inside-out meniscal repair, the outer suture should be inserted into the remaining peripheral meniscus or the capsule near the meniscus.

Introduction

The meniscus plays important roles such as shock absorption, joint stabilization, load transmission, and lubrication in the knee joint [2, 13, 19, 21, 26]. Due to its mechanical demand, the meniscus is frequently torn in athletic activities, and the frequency of meniscal injury is over 30% in total acute knee injury [22]. For treatment of the meniscal injury, the meniscectomy had been generally chosen [7, 14], however, the meniscectomy has found to result in the articular cartilage degeneration and osteoarthritis [16, 18]. Thus, the meniscal repair is proactively chosen for meniscal treatment to preserve the biomechanical function of meniscus [3,4,5,6, 10,11,12, 25].

Longitudinal meniscal tear in the red zone (blood supplied zone) is the best for meniscal repair, while the inside-out technique is commonly applied to meniscus repair [9].. As the longitudinal meniscal tears are observed not only at the mid-substance but also at the peripheral meniscus-synovium junction, one thread inserts into the meniscus inside of the tear and the other thread passes through the meniscus outside of the tear or the capsule, depending on the meniscus width outside of the tear. In case of meniscal repair including capsule, as the strength of the meniscus is quite different from the strength of capsule, the capsule can be damaged easily by suture material compared to the meniscus. However, the effect of the difference between stitching regions (meniscus-meniscus vs meniscus-capsule) on post-surgical stability is unclear, though the secure and strong suture method in meniscal repair is required to achieve satisfactory outcomes.

Previous studies evaluated the suture methods of the meniscus repair [1, 2, 20, 23]. Aık et al. compared the suture strength using bovine knees in meniscal repair among 5 suture techniques; horizontal mattress, vertical mattress, knot-end, vertical, and vertical loop, and described that the largest ultimate failure load occurred in the vertical mattress suture technique. However, as this report applied the tensile test to the meniscus without synovial capsule, ligaments and bones [1], the condition was different from the physiological state. Iuchi et al. firstly clarified the suture strength in meniscal repair for the physiological meniscus attached to the synovial capsules and bones [15]. Therefore, the aim of the present study was to biomechanically compare the suture stability between meniscus-meniscus and meniscus-capsule suture techniques for the longitudinal meniscal tear in the physiological condition. Our hypotheses were 1) the gap of suture site in the meniscus-capsular suture technique was larger than that in the meniscus-meniscus technique during the cyclic loading test and 2) the failure load did not differ between those techniques.

Method

Specimen preparation

Twenty-seven porcine knee joints were used in the present study. The porcine were approximately 100 kg in weight with a mean age of 6 months. As all knee samples were obtained from the food industry and no animals were killed or sacrificed for this study, the study protocol was reviewed and determined not to require oversight by the institutional review board in our institutes. Specimens were stored in − 20 °C freezer and thawed with 4 °C temperature for 24 h prior to the test. All soft tissues around the knee joint were carefully dissected down while the medial meniscus and the medial joint capsule including medial collateral ligament were preserved. The inner portion of medial meniscus was sharply cut off along the meniscal longitudinal fiber with the scalpel while 3-mm width of the peripheral portion was preserved. Both ends of the excised meniscus were stitched by Krackow stitch using No.5 polyester sutures (Ethibond; EXCEL, ETHICON, Johnson & Johnson, USA) (Fig. 1).

Fig. 1
figure1

Specimen setup for the test. Femur and tibia were fixed to the bottom of the apparatus using custom-made jigs, while sutures on both ends of the meniscus were tied over the upper jig of the apparatus connected to the load cell

Meniscal repair

2-0 polyester sutures with two straight needles on both sides of a thread (Stryker Japan, Tokyo) were used for meniscal repair. Single stich was applied with this 2-0 polyester suture at the center of the excised meniscus on femoral side in the inside-out technique (Fig. 2). The specimens were divided into the following 3 groups (n = 9 to each group) based on the stitching technique. One needle was inserted at 3 mm apart from the outer site of the excised meniscus and was passed through the peripheral meniscus in all groups. The other needle was inserted through 1) the peripheral meniscus (Group A), 2) capsule just above the meniscus (Group B), and 3) capsule at 10 mm apart from the meniscus-capsule junction (Group C), respectively (Fig. 3). Then, the suture was manually tied on the capsule with four square knots at 30 degree of knee flexion. All knot tying were performed by one orthopaedic surgeon with more than 20-year experience (T.M).

Fig. 2
figure2

Suture placing for the longitudinal meniscus tear. A single stich was applied at the center of the excised meniscus on femoral side in the inside-out manner

Fig. 3
figure3

Stitching techniques. One needle was inserted into the meniscal body in all groups, while the other needle was inserted through 1) the peripheral meniscus (Group A: red dot), 2) capsule just above the meniscus (Group B: blue dot), and 3) capsule at 10 mm apart from the meniscus-capsule junction (Group C: green dot)

Biomechanical tests

Biomechanical tests were performed using material testing apparatus (AUTOGRAPH AG-IS, SHIMADZU, Kyoto, Japan). Femur and tibia were fixed to the bottom of the apparatus using custom-made jigs and No. 5 sutures on both ends of the excised meniscus were tied over the upper jig of the apparatus connected to the load cell. Then, the pre-conditioning was performed by applied 20 N of tensile load for 5 min. In the cyclic loading test, the cyclic load between 5 to 20 N with 20 mm/min velocity was applied 300 times followed the previous reports [8]. To assess the suture gap of the stitched site, suture insertion points were marked as a dot by surgical marker prior to the test, and both dots were recorded by a video camera (HDR-CX370V; SONY, Tokyo, Japan) during the test. Then, the motion of the dots during the test was tracked using a motion tracking system (Motion analyzer VW-9000, KEYENCE, Japan) based on the recorded movie. The gap between both dots was calculated before and after the test with a 5 N tensile force application state. After the cyclic loading test, the load-to-failure test was performed with 5 mm/min velocity referred to previous reports [15, 28], and recorded ultimate failure load and failure mode. All biomechanical tests were randomly performed among three groups.

Statistical analysis

The study compared data among groups using a 1-way analysis of variance (ANOVA). Then, the statistical significance of the data between two groups in each combination was considered by Bonferroni correction, and it was set at p < 0.0167.

Result

In the cyclic loading test, the suture gap was 0.68 ± 0.26 mm in Group A, 1.08 ± 0.36 mm in Group B, and 1.94 ± 0.57 mm in Group C respectively (Fig. 4). There was a significant difference between two groups in multiple comparisons. P-values in Group A vs B, Group A vs C and Group B vs C were 0.01, 0.001 and 0.002, respectively.

Fig. 4
figure4

The gap at the suture site after 300 times of cyclic loading. There was a significant difference among three groups. * p < .0015

In the load-to-failure test, the ultimate failure load was 59.1 ± 13.6 N in Group A, 60.0 ± 7.9 N in Group B, and 57.4 ± 4.7 N in Group C, respectively (Fig. 5). There was no significant difference between two groups in any combinations. P-values in Group A vs B, Group B vs C and Group A vs C were 0.8, 0.8 and 0.2, respectively. All specimens failed at the knot in ultimate failure load test.

Fig. 5
figure5

Ultimate failure load. There was no significant difference among three groups

Discussion

The key finding of the present study was that the meniscus-capsule stitching method in the inside-out meniscal repair affects the suture gap of the repaired site during cyclic loading while there was no significant difference in the load-to-failure test.

The suture gap of the repaired site in Group B and C was significantly larger than that in Group A during cyclic loading. The cause of the suture gap widening was possible to be the damage of the tissue and the stitching structure. The meniscus is generally reinforced by collagen fiber [24], which is mainly oriented in a circular manner in the main region of the meniscus. Those fibers transmit the radial force to the circular manner and to the anterior and posterior horn ligament. In the present study, as the main fiber direction was perpendicular to the loading direction [24], the structure of the meniscus may have enough strength to the suture and its tensile loaded direction. On the other hand, although the joint capsule is also consisted by collagen fiber, its orientation is not homogeneous, and the strength to the loading direction was much smaller than the mid-substance of the meniscus [27]. Therefore, the capsule might be easier to be damaged by the suture material than the meniscus during the cyclic loading, and, in fact, a small tear occurred at the suture insertion point after the test.

There was no statistical difference in the ultimate failure load between each group, and all subjects in all groups showed knot failure. The previous reports also indicated that the failure mode in the load to failure test was mainly the knot failure [1, 2, 20, 23]. Then, the suture can be damaged in tying a knot the knot tying procedure for the meniscus repair may made a weak point in the stitching. Yokoi et al. indicated that the flat and wide shape suture material showed a higher ultimate failure load compared to conventional and hollow sutures [28]. Therefore, the suture material should be considered to keep the post-surgical stability of the stitched site. Moreover, in the clinical practice, multiple sutures are used for meniscal repair based on the size of the tear. Previously, Iuchi et al. reported that the multiple sutures generated much higher strength compared to the single suture in the meniscal repair [15]. Thus, meniscal repair with number of sutures can get enough strength in the surgical setup, though one suture was weaker than the meniscus tissue.

There were some limitations in this study. First, the porcine specimens were used for the test as a replacement for the human specimens. However, several previous studies reported that the porcine meniscus had comparable properties to those of human meniscus [8, 17], and the present testing setup was acceptable to determine the post-surgical stability of the stitched site in the meniscus repair. Second, the testing setup was only set in time zero, and the consequence of the stitched region in meniscus repair after surgery was not clarified. Third, the loading direction was not physiological, as range of motion exercise and weight bearing training are commonly performed in the post-operative rehabilitation program. However, the severe environment such as directly pulling the suture site could be important to detect the essential effect of suture technique. In future works, the physiological loading will apply to determine the magnitude of the suture gap. Finally, the point at which the needle came out from the capsule was not precisely assessed, although the insertion site of needle was evaluated. The needle direction after inserting to meniscus is also a key and should be controlled, as the needle direction can also affect the amount of capsule sutured behind the meniscus. However, the needle inserted to the mid-substance of the meniscus was direct-visually passed into the peripheral meniscus and was pushed to proximal. Thus, the effect of the amount of capsule behind the meniscus on suture gap could be minimized in the present study.

Conclusion

The stitching region in the inside-out technique for longitudinal meniscal tear affected the stability of the tear site, and stitching the mid-substance region of the meniscus provides a good stability in response to cyclic tensile loading. In addition, the stitching region did not affect the ultimate failure load.

References

  1. 1.

    Aşık M, Şener N, Akpınar S, Durmaz S, Göksan A (1997) Strength of different meniscus suturing techniques. Knee Surg Sports Traumatol Arthrosc 5(2):80–83

    Article  Google Scholar 

  2. 2.

    Barber FA, Stone RG (1985) Meniscal repair. An arthroscopic technique. J Bone Joint Surg Br 67(1):39–41

    CAS  Article  Google Scholar 

  3. 3.

    Barber FA, Herbert MA, Schroeder FA, Aziz-Jacobo J, Sutler MJ (2009) Biomechanical testing of new meniscal repair techniques containing ultra high-molecular weight polyethylene suture. Arthroscopy 25(9):959–967

    Article  Google Scholar 

  4. 4.

    Cannon WD Jr, Morgan CD (1994) Meniscal repair: arthroscopic repair techniques. Instr Course Lect 43:77–96

    PubMed  Google Scholar 

  5. 5.

    Chang HC, Nyland J, Caborn DN, Burden R (2005) 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. Am J Sports Med 33(12):1846–1852

    Article  Google Scholar 

  6. 6.

    DeHaven KE (1985) Meniscus repair–open vs. arthroscopic. Arthroscopy 1(3):173–174

    CAS  Article  Google Scholar 

  7. 7.

    Englund M, Roos EM, Roos HP, Lohmander LS (2001) Patient-relevant outcomes fourteen years after meniscectomy: influence of type of meniscal tear and size of resection. Rheumatology. 40:631–639

    CAS  Article  Google Scholar 

  8. 8.

    Fantasia F, Potalivo G, Placella G, Fantasia L, Cerulli G (2012) Meniscal sutures: biomechanical study of mulberry and horizontal loop techniques. J Orthop Traumatol 13(1):13–19

    Article  Google Scholar 

  9. 9.

    Henning C (1983) Arthroscopic repair of meniscus tears. Orthopedics 6(9):1130–1132

    CAS  Article  Google Scholar 

  10. 10.

    Henning CE, Clark JR, Lynch MA, Stallbaumer R, Yearout KM, Vequist SW (1998) Arthroscopic meniscus repair with a posterior incision. Instr Course Lect 37:209–221

    Google Scholar 

  11. 11.

    Horibe S, Shino K, Nakata K, Maeda A, Nakamura N, Matsumoto N (1995) Secondlook arthroscopy after meniscal repair. Review of 132 menisci repaired by an arthroscopic inside-out technique. J Bone Joint Surg Br 77(2):245–249

    CAS  Article  Google Scholar 

  12. 12.

    Horibe S, Shino K, Maeda A, Nakamura N, Matsumoto N, Ochi T (1996) Results of isolated meniscal repair evaluated by second-look arthroscopy. Arthroscopy 12:150–155

    CAS  Article  Google Scholar 

  13. 13.

    Hsieh HH, Walker PS (1976) Stabilizing mechanisms of the loaded and unloaded knee joint. J Bone Joint Surg Am 58(1):87–93

    CAS  Article  Google Scholar 

  14. 14.

    Hughston JC (1975) A simple meniscectomy. J Sports Med 3:175–187

    Article  Google Scholar 

  15. 15.

    Iuchi R, Mae T, Shino K, Matsuo T, Yoshikawa H, Nakata K (2017) Biomechanical testing of transcapsular meniscal repair. J Exp Orthop 4(1):2

  16. 16.

    Johnson RJ, Kettelkamp DB, Clark W, Leaverton P (1974) Factors affecting late results after meniscectomy. J Bone Joint Surg Am 56:719–729

    CAS  Article  Google Scholar 

  17. 17.

    Joshi MD, Suh JK, Marui T, Woo SL (1995) Interspecies variation of compressive biomechanical properties of the meniscus. J Biomed Mater Res 29(7):823–828

    CAS  Article  Google Scholar 

  18. 18.

    Krause WR, Pope MH, Johnson RJ, Wilder DG (1976) Mechanical changes in the knee after meniscectomy. J Bone Joint Surg Am 58:599–604

    CAS  Article  Google Scholar 

  19. 19.

    Kurosawa H, Fukubayashi T, Nakajima H (1980) Load-bearing mode of the knee joint: physical behavior of the knee joint with or without menisci. Clin Orthop Relat Res 149:283–290

    Article  Google Scholar 

  20. 20.

    Lee YHD, Nyland J, Burden R, Caborn DNM (2012) Cyclic test comparison of all-inside device and inside-out sutures for radial meniscus lesion repair: an in vitro porcine model study. Arthroscopy 28(12):1873–1881

    Article  Google Scholar 

  21. 21.

    Mac CM (1950) The movements of bones and joints; the synovial fluid and its assistants. J Bone Joint Surg Br 32-B(2):244–252

    Article  Google Scholar 

  22. 22.

    Majewski M, Susanne H, Klaus S (2006) Epidemiology of athletic knee injuries: a 10-year study. Knee 13(3):184–188

    CAS  Article  Google Scholar 

  23. 23.

    Masoudi A, Beamer BS, Harlow ER, Manoukian OS, Walley KC, Hertz B, Haeussler C, Olson JJ, Zurakowski D, Nazarian A, Ramappa AJ, DeAngelis JP (2015) Biomechanical evaluation of an all-inside suture-based device for repairing longitudinal meniscal tears. Arthroscopy 31(3):428–434

    Article  Google Scholar 

  24. 24.

    Petersen W, Tillmann B (1998) Collagenous fibril texture of the human knee joint menisci. Anat Embryol 197:317–324

    CAS  Article  Google Scholar 

  25. 25.

    Tachibana Y, Sakaguchi K, Goto T, Oda H, Yamazaki K, Iida S (2010) Repair integrity evaluated by second-look arthroscopy after arthroscopic meniscal repair with the FasT-Fix during anterior cruciate ligament reconstruction. Am J Sports Med 38(5):965–971

    Article  Google Scholar 

  26. 26.

    Voloshin AS, Wosk J (1983) Shock absorption of meniscectomized and painful knees: a comparative in vivo study. J Biomed Eng 5(2):157–161

    CAS  Article  Google Scholar 

  27. 27.

    Yamashita T, Minaki Y, Ozaktay AC, Cavanaugh JM, King AI (1996) A morphological study of the fibrous capsule of the human lumbar facet joint. Spine 21(5):538–543

    CAS  Article  Google Scholar 

  28. 28.

    Yokoi H, Mae T, Iuchi R, Take Y, Tachibana Y, Shimomura K, Ohori T, Shino K, Yoshikawa H, Nakata K (2017) Novel flat and wide meniscal repair material improves the ultimate load of knot breakage in a porcine trans-capsular meniscal repair model. J Exp Orthop 4(1):41

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by a grant from Japan Society for the Promotion of Science, JSPS KAKENHI 20 K09409.

Informed consent

Animal study.

Funding

Not applicable.

Author information

Affiliations

Authors

Contributions

Substantial contributions to the conception or design of the work: T.M. The acquisition and analysis: S.Y, T.M. Interpretation of data for the work: S.Y, T.M, I.O, T.H, S.K. Drafting the work or revising it critically for important intellectual content: T.M, K.N. Final approval of the version to be published: S.Y, T.M, I.O, T.H, S.K, K.N. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: S.Y, T.M, I.O, T.H, S.K, K.N.

Corresponding author

Correspondence to Tatsuo Mae.

Ethics declarations

Ethics approval

Not applicable. (as all specimens were got from a butcher).

Competing interests

All authors have no conflict of interest.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yamakawa, S., Mae, T., Ogasawara, I. et al. Placement of sutures for inside-out meniscal repair: both sutures through meniscal tissue reduces displacement on cyclical loading. J EXP ORTOP 8, 94 (2021). https://doi.org/10.1186/s40634-021-00417-z

Download citation

Keywords

  • Meniscus
  • Repair
  • Inside-out technique
  • Longitudinal tear
  • Suture