Study on the resistance of the supraspinous tendon using simple, matress and mason allen stitches

Abstracts

OBJETIVO: O objetivo do trabalho foi comparar a resistência entre os pontos simples, duplo e Mason-Allen modificado, utilizados para o reparo do manguito rotador, e verificar se há diferença significativa que justifique a utilização do ponto do tipo Mason-Allen modificado ao invés dos pontos simples ou duplo. MÉTODO: Retiramos tendões do músculo supra-espinal de 15 cadáveres humanos frescos (30 ombros), com a média de idade de 45 anos. Os testes foram realizados na máquina universal de ensaio mecânico Kratos® 500/2000 e os resultados submetidos aos testes estatísticos de t-student, análise de variância (ANOVA), comparação múltipla de Bonferroni e calculadas as correlações de Pearson. Os testes foram realizados ao nível de significância de 5%. RESULTADOS: Não houve diferença significativa com relação à idade, ao tamanho das amostras e deslocamento do tendão. A resistência variou com média de 127,50 N com o ponto simples, 163,95 N com o duplo e com o ponto de Mason-Allen modificado esta foi de 198,45 N. CONCLUSÃO: não existe diferença da resistência no tendão quanto à falha na interface sutura - tendão comparando-se o ponto duplo com o Mason-Allen modificado e os pontos simples e duplo, porém há diferença quando comparados os pontos simples e Mason-Allen modificado.

Tendões; Técnicas de Sutura; Resistência à tração

ORIGINAL ARTICLE

Study on the resistance of the supraspinous tendon using simple, matress and Mason Allen stitches

Roberto Yukio Ikemoto; Joel Murachovsky; Luis Gustavo Prata Nascimento; Rogério Serpone Bueno; Luis Henrique Almeida; Eric Strose

Discipline of Diseases of the Locomotive Apparatus of Faculdade de Medicina do ABC

Mailing Address

ABSTRACT

OBJECTIVE: The purpose of this study was to compare the rotator cuff tendon resistance at the interface tendon-suture using three different sorts of stitches (simple, mattress and modified Mason-Allen).

METHODS: To do this, 30 rotator cuffs were totally dissected from 15 specimens, which were 45 years old on average. The tests were done using a Kratos^® 500/2000 machine and the statistical analyses applied were the Student t-test, ANOVA test, Multiple Bonferroni Comparison, and Pearson's correlation coefficients; all the analyses used a significance level of 5%.

RESULTS: No significant difference was observed regarding the age, sample sizes and tendon displacement. The tendon resistance was 127.50 N on average when Simple stitches were used, 163.95 N when Double stitches were used and 198.45 N when the Modified Mason-Allen Knot was used.

CONCLUSION: Although the tendon resistance at the interface tendon-suture was higher using the Modified Mason-Allen stitches than it was when using the Double and Simple Knots, there was no difference in tendon resistance when using the Modified Mason-Allen and Double stitches. On the other hand, we found that tendon resistance was higher when using Modified Mason-Allen stitches as compared to tendon resistance when using Simple stitches.

Keywords: Tendons. Suture techniques. Tensile strength.

INTRODUCTION

The surgical treatment of rotator cuff tendon lesions through the arthroscopic route has been widely broadcast and popularized with the development of new techniques and materials.¹ The refinement of these is the topic of clinical and experimental research by several authors.^2-4

The good clinical results obtained by means of this treatment method, signifying good joint mobility and motor force, depend on the reinsertion of the rotator cuff muscle tendons in their bone bed. For this purpose, it is necessary to achieve stabilization of the stump of the tendon sutured to the bone tissue until its total healing.^3,5,6

Various studies have encountered high rates of re-rupture of the rotator cuff tendons in patients submitted to treatment through the arthroscopic route, citing as causes: loosening of the anchor, which may occur due to poor bone quality or technical error; snapping of the suture threads, both due to their resistance and in passage through the anchor orifice and fault in the tendon-suture interface, which is provided by the resistance of the tendon to the different types and methods of suture stitches.^3,5-7

The repair of rotator cuff muscle tendons through the arthroscopic route is a technique that demands knowledge, skill and training on the part of the surgeon, with a long learning curve, due also to the inherent technical difficulties such as the positioning and the inclination of the anchors, the passage of the threads through the tendon and the suture with the different sorts of knot.¹

Therefore, simple stitches, those in which one of the threads of the anchor passes once through the tendon, have been used with greater frequency, although studies have demonstrated that modified Mason-Allen stitches afford greater traction resistance in tendons. This probably occurs because the latter are technically harder to apply through the arthroscopic route.⁷

The aim of the study is to compare resistance among simple, mattress and modified Mason-Allen stitches, and thus to verify whether there is a significant difference that justifies the use of the modified Mason-Allen type stitch instead of the simple or mattress stitches.

MATERIAL AND METHODS

For the preparation of this study, biomechanical assays were conducted on supraspinous muscle tendons of 15 fresh human cadavers (30 shoulders) taken from the Coroner's Service of Santo André, an annex of Faculdade de Medicina do ABC. All the cadavers were of the male gender, with mean age 45 years and six months (25 to 75 years). (Table 1)

The pieces were removed, measured and stored in 0.9% saline (Figure 1), then sent to the analyses laboratory of SOGEFI (Filter Division do Brazil), where the tests were executed in the Kratos^® 500/2000 series 5197 universal mechanical testing machine with load cell of 490 N and load application of 20 mm/minute. All the analyses were carried out in a period of less than four hours from the removal of the samples up to the performance of the tests. (Figure 2)

We used Durabraid^® 2 suture (braided polyester) passed 1 cm from the free edge of the tendon. In the mattress and modified Mason-Allen stitches we sought to keep the thread passages 1 cm apart. (Figure 3)

We used the same type of suture stitch on both sides (right and left) of the same cadaver. We started with the simple stitches, used the mattress stitches in the second specimen and the modified Mason Allen type stitches in the third, and thus maintained the same sequence in the subsequent pieces.

The muscular part was fixed on the clip of the proximal portion of the apparatus, alongside the load cell, and the thread of the suture stitch was tied to the fixed bar, at the other end of the apparatus.

We quantified the degree of displacement of the tendon starting from the tension of 58.8 N, which corresponds to the moment when the thread and the tendon appeared tense.

We applied the paired statistical student's t-test to evaluate whether there was a statistically significant difference in comparing the measurements of size, displacement and resistance between right and left sides of the same cadaver.

The variance analysis (ANOVA) was used to evaluate whether there was a statistical difference in terms of the tendon resistance at the different types of stitch used and the multiple Bonferroni comparison to demonstrate in which kinds of stitch this difference occurred.

Pearson's correlation was used to evaluate whether the cadavers' age could influence tendon size (in mm²), in its displacement and in the tendon resistance at the suture point, in each one of the types of suture performed.

All the tests were conducted at the significance level of 5%.

RESULTS

The mean size of the samples was 13.5750 mm² ± 1.6917 (11.9427 mm² to 15.2073 mm²).

The mean displacement of the tendon on the right side was 1.74 cm ± 0.41 cm and on the left side 1.95cm ± 0.36 cm, averaging 1.85 cm ± 0.39 cm.

As regards the mean resistance of the tendon, on the right side we obtained the value of 160.65 N ± 46.04 and on the left side 165.95 N ± 44.27, averaging 163.30 N ± 44.46.

The student's t-test demonstrated that there was no statistical difference between right and left sides in relation to size (p=0.510), displacement (p=0.165) and resistance (p=0.451) with p>0.05 (Table 2).

As regards displacement, when we used the modified Mason-Allen stitch and the simple stitch, this was 1.88 cm on average with standard deviation of ± 0.43 cm for the former and of ± 0.49 for the simple stitch. When we used the mattress stitch, the result was 1.78 cm ± 0.26 cm on average.

Analyzing tendon resistance, in using the simple stitch, the mean value was 127.50 N ± 34.55, with the mattress stitch 163.95 N ± 41.18 and with the modified Mason-Allen the mean value was 198.45 N ± 26.13. (Figure 4)

With the assistance of the ANOVA variance analysis, we verified that there was no statistically significant difference in terms of sample size (p=1.000) and tendon displacement (p=0.817) in relation to the stitches used. However, it could be noticed that the modified Mason-Allen stitch differs from the others in terms of resistance. (p=0.001). (Table 3)

We used the multiple Bonferroni comparison for analysis of resistance among the different pairs of stitches in relation to one another and this demonstrated statistically significant difference between the modified Mason-Allen and simple stitches (p<0.001), but did not demonstrate any difference between simple and mattress (p=0.077), or between modified Mason-Allen and mattress (0.102). (Table 4)

In the analysis of Pearson's correlations, we observed that only in the specimens sutured with mattress stitching, the higher the age, the lower the displacement undergone (p=0.047). Age had no influence in the other attempts at correlations (p>0.005) (Table 5).

DISCUSSION

Due to the high rate of rotator cuff re-rupture, particularly in cases of extensive lesions, as reported by some authors,^2,4,7-9 there is growing interest in the development of new techniques for improvement of the results of the treatments of these lesions.^4,10

The ideal repair of the rotator cuff lesion should have considerable initial resistance force, not allowing mobility and contact failure between tendon and bone. This serves to maintain mechanical stability until its complete healing, restoring the muscle-tendon-bone unit and favoring recovery of the muscular strength of the shoulder.^3,4,11

To analyze the different kinds of stitch proposed, we excluded other repair failure factors related to the tendon-bone unit such as: poor bone quality, technical errors in the insertion of the anchors, loosening of these anchors and faults of the suture thread in the anchor orifice. The tissue was excised from the bone, thus allowing isolated evaluation of the stitch since most faults occur when the suture tractions the tendon.^4,12,13

The suture material and the safety of the knot are also factors that influence repair. We used No. 2 (Durabraid^®) braided polyester, which has been reported to be the most suitable choice in rotator cuff repairs.^14,15

According to our results, there was no statistically significant difference between right and left sides in relation to sample size, displacement and tendon resistance. Analyzing the different kinds of stitch separately in terms of their resistance, we verified that the simple stitch is inferior to the other two. Gerber et al.³ also arrived at the conclusion that the stitch used most often, the simple one, was the weakest in comparison to several other kinds of stitch. He also emphasized that this stitch, although weak, would not strangulate the tendon, allowing coaptation of the tendon to the bone in the absence of tension, proving useful for small rotator cuff lesions.³

The modified Mason-Allen stitch, like in literature, was superior in numerical terms to the simple and mattress stitches,^3,4,7,13 yet when compared separately with the mattress stitch, this difference was not statistically significant, and this significance was only confirmed between the simple and modified Mason-Allen stitches. This stitch, however, has the disadvantage of difficulty of its performance by the arthroscopic route, so the other two stitches are used much more frequently.⁴ Moreover, Schneeberger, et al¹⁰ showed that, arthroscopically, the modified Mason-Allen stitch did not improve the resistance of the rotator cuff tendon lesion repair when used together with anchors due to the fault of the anchor and of the stitch in its orifice. On the other hand, Scheibel and Habermeyer,¹³ in 2003, obtained outstanding results using this kind of stitch, achieving excellent initial fixation strength and adequate mechanical stability, allowing tendon healing.

A limiting factor of this study was the non-performance of the cyclic force test, approximating the stitch tension to the real scenario. However, in other studies similar to this one, no statistically significant difference was observed in relation to displacement and elongation of the sample when this method was applied.⁴

Another fact to be emphasized is the need for greater casuistry, as the numerical values, in relation to resistance among the different stitches, exhibited a small difference, meaning that the only statistically significant connection was between the simple stitch and the modified Mason-Allen.

CONCLUSION

In absolute numbers the mean resistance with the Mason-Allen stitch is higher than the mattress stitch which, in turn, is higher than the simple stitch. Nevertheless, there is no difference of resistance in the tendon in terms of fault in the suture-tendons interface comparing the double stitch with the modified Mason-Allen suture and the simple stitch with the mattress suture, yet there is a difference when the simple and modified Mason-Allen stitches are compared.

REFERENCES

• 1. Yamaguchi K, Levine WN, Marra G, Galas LM, Klepps S, Flatow E. Transitioning to arthroscopic rotator cuff repair: the pros and cons. J Bone Joint Surg Am. 2003;85:144-55.
• 2. Burkhart SS, Danaceau SM, Pearce CE Jr. Arthroscopic rotator cuff repair. Analysis of results by tear size and by repair technique - margin convergence versus direct tendon - to- bone repair. Arthroscopy. 2001;17:905-12.
• 3. Gerber C, Schneeberger A, Beck M, Schlegel U. Mechanical strength of repairs of the rotator cuff. J Bone Joint Surg Br. 1994;76: 371-9.
• 4. Ma CB, MacGillivray JD, Clabeaux J, Lee S, Otis JC. Biomechanical evaluation of arthroscopic rotator cuff stitches. J Bone Joint Surg Am. 2004;86:1211-6.
• 5. Boileau P, Brassart N, Watkinson D, Carles M, Hatzidakis AM, Sumant GK. Arthroscopic repair of full-thickness tears of the supraspinatus: does the tendon really heal? J Bone Joint Surg Am. 2005;87:1229-39.
• 6. Warner JP, Gerber C. ¨Treatment of massive rotator cuff tears: posterior-superior and anterior-superior¨. In: Iannotti JP. The rotator cuff. Current concepts and complex problems. Illinois: American Academy of Orthopaedic Surgeons; 1998. p. 59-94.
• 7. Gerber C, Schneeberger AG, Perren SM, Nyffeler RW. Experimental rotator cuff repair: a preliminary study. J Bone Joint Surg Am. 1999;81:1281-90.
• 8. Ellman H, Hanker G, Bayer M. Repair of the rotator cuff. End-result study of factors influencing reconstruction. J Bone Joint Surg Am. 1986;68:1136-44.
• 9. Ianotti JP, Bernot MP, Kuhlman JR, Kelley MJ, Willians GR. Postoperative assessment of shoulder of shoulder function: a prospective study of full-thickness rotator cuff tears. J Shoulder Elbow Surg. 1996;5:449-57.
• 10. Schneeberger AG, Roll AV, Kalberer F, Jacob HAC, Gerber C. Mechanical strength of arthroscopic rotator cuff repair techniques. J Bone Joint Surg Am. 2002;84:2152-60.
• 11. Harryman DT 2nd, Mack LA, Wang KY, Jackins SE, Richardson ML, Matsen FA 3rd. I. Repairs of the rotator cuff: Correlation of functional results with integrity of the cuff. J Bone Joint Surg Am. 1991;73:982-9.
• 12. Cummins CA, Murrel GA. Mode of failure for rotator cuff repair with suture anchors identified at revision surgery. J Shoulder Elbow Surg. 2003;12:128-33.
• 13. Scheibel MT, Habermeyer P. A modified Mason-Allen technique for rotator cuff repair using suture anchors. Arthroscopy. 2003;19:330-3.
• 14. Demirhan M, Atalar AC, Kilicoglu O. Primary fixation strength of rotator cuff repair techniques: a comparative study. Arthroscopy. 2003;19:572-6.
• 15. Burkhart SS, Wirth MA, Simonich M, Salem D, Lanctot D, Athanasiou K. Knot security in simple sliding knots and its relationship to rotator cuff repair: how secure must the knot be? Arthroscopy 2000;16:202-7.

Publication Dates

• Publication in this collection
  23 Apr 2010
• Date of issue
  2010

History

• Accepted
  22 Oct 2009
• Received
  27 Jan 2009