Mann-Whitney test was used to compare the force causing the initial gap and 2-mm gap between repaired tendons using Bunnell suture and Unhas suture. In those cases, a level of P<0.05 was considered to be significant.
The gap resistance and ultimate strength of repaired tendon are the primary parameters that define the mechanical properties of a surgical repair. Adequate mechanical strength is essential for a repair to resist gapping and failure. Maintaining a certain baseline tension on the core suture during surgery greatly benefits gap resistance.19,33 Peripheral suture could also significantly increase the strength of tendon repairs.19,20,34,35,39,40
Since Tsuge technique requires looped suture or double arm suture which are not always available in every health service centers, Unhas suture simply uses the conventional suture material. Author defined Unhas suture as a simple intratendon sutures, parallel with the tendon collagen fibers, which carries stress of the repair away from the ends of the tendon. The nodes provide approximation of ends of tendon rupture, thus reducing the tendon gap formation so the tendon healing is guaranteed.
In Human, various studies had evaluated the forces to tendon during passive and active mobilization.41–43 Tendon forces up to 9 N were present during passive mobilization of the fingers.19,42,44 In this study, the mean initial gap forces in repaired tendon using Unhas suture was 9.76 N and using Bunnell suture was 9.16 N and the result was higher compared with the forces present during passive mobilization in which Unhas suture and Bunnell suture were assumed to be able to resist the gap formation in passive mobilization under supervision if applied in human tendon repair.
There were limitations to this study. These values are estimated from experiments on rooster tendons and therefore requires further studies which included cadaveric studies and with the intact pulley system to support its use on clinical setting. Cyclic loading was not conducted and linier load to failure may not mimic physiological conditions.23,46,47 In this study, Nylon 4-0 was chosen due to the size of our tendon specimens and its use is supported by multiple researches both in vitro and in vivo.19 Possible of using other specimens, size, thread materials, and number of loops could be applied depends on the study design.
1. Mackenzie D. The history of sutures. Med Hist. 1973;17:58–168.
2. Deepak M, Subraramanian CS, Senthilvelan, et al. A prospectic randomised study on cosmetic outcome between simple suturing and mattress suturing in hernioplasty. Int J Modn Res Revs. 2014;2:418–420.
3. Viinikainen A. Development of a New Flexor Tendon Repair Technique Performed With Bioabsorbsorbable Poly-L/D-Lactide (PLDLA) 96/4 Suture: An Experimental Ex Vivo Study
[Academic Dissertation] Helsinki: University of Helsinki; 2008.
4. Manske PR. History of flexor tendon repair
. Hand Clin. 2005;21:123–127.
5. Strickland JW. Development of flexor tendon surgery: twenty-five years of progress. J Hand Surg Am. 2000;25:214–235.
6. Kotwal PP, Ansari MT. Zone 2 flexor tendon injuries: venturing into the no man’s land. Indian J Orthop. 2012;46:608–615.
7. Rawson S, Cartmell S, Wong J. Suture techniques for tendon repair
: a comparative review. Muscles Ligaments Tendons J. 2013;3:220–228.
8. Adamson JE, Wilson JN. The history of flexor-tendon grafting. J Bone Joint Surg. 1961;43-A:709–716.
9. Verdan CE. Primary repair of flexor tendons. J Bone Joint Surg Am. 1960;42:647–657.
10. Singh R, Rymer B, Theobald P, et al. A review of current concepts in flexor tendon repair
: physiology, biomechanics, surgical technique and rehabilitation. Orthop Rev. 2015;7:101–105.
11. Strickland JW. The scientific basis for advances in flexor tendon surgery. J Hand Ther. 2005;18:94–110.
12. Tang JB. Clinical outcomes associated with flexor tendon repair
. Hand Clin. 2005;21:199–210.
13. Lister GD, Kleinert HE, Kutz JE, et al. Primary flexor tendon repair
followed by immediate controlled mobilization. J Hand Surg. 1977;2:441–451.
14. Strickland JW, Glogovac SV. Digital function following flexor tendon repair
in zone II: a comparison of immobilization and controlled passive motion techniques. J Hand Surg. 1980;5:537–543.
15. Cullen KW, Tolhurst P, Lang D, et al. Flexor tendon repair
in zone 2 followed by controlled active mobilisation. J Hand Surg. 1989;14B:392–395.
16. Small JO, Brennen MD, Colville J. Early active mobilisation following flexor tendon repair
in zone 2. J Hand Surg. 1989;14B:383–391.
17. Bainbridge LC, Robertson C, Gillies D, et al. A Comparison of post-operative mobilization of flexor tendon repairs with“passive flexion-active extension” and “controlled active motion” techniques. J Hand Surg. 1994;19B:517–521.
18. Baktir A, Türk CY, Kabak S, et al. Flexor tendon repair
in zone 2 followed by early active mobilization. J Hand Surg. 1996;21B:624–628.
19. Tang JB, Xie RGTang JB, Amadio PC, Guimberteau JC, Chang J. Biomechanics of core and peripheral tendon repairs. Tendon Surgery of the Hand. Philadelphia: Elsevier Saunders; 2012:2035.
20. Merrell GA, Wolfe SW, Kacena WJ, et al. The effect of increased peripheral suture purchase on the strength of flexor tendon repairs. J Hand Surg Am. 2003;28:464–468.
21. Mishra V, Kuiper JH, Kelly CP. Influence of core suture material and peripheral repair technique on the strength of Kessler flexor tendon repair
. J Hand Surg. 2003;28B:357–362.
22. Shaieb MD, Singer DI. Tensile strengths of various suture techniques. J Hand Surg. 1997;22B:764–767.
23. Barrie KA, Tomak SL, Cholewicki J, et al. The role of multiple strands and locking sutures on gap formation
of flexor tendon repairs during cyclical loading. J Hand Surg. 2000a;25A:714–720.
24. Tanaka T, Amadia PC, Zhao CF, et al. Biomechanical properties of locking versus grasping suture. Summer Bioengineering Conference, Minnesota Orthopaedic Biomechanics Laboratory
; Rochester, Minnesota, 2003;635–636.
25. Viinikainen A, Goransson H, Ryhanen J. Primary flexor tendon repair
techniques. Scand J Surg. 2008;97:333–340.
26. Cannon DLCanale ST, Beaty JH. Flexor and extensor tendon injuries. Campbell’s Operative Orthopaedics, 12th ed. Philadelphia: Elsevier Mosby; 2013:3249.
28. Sebastin SJ, Ho A, Karjalainen T, et al. History and evolution of the kessler repair. J Hand Surg. 2013;38A:552–561.
29. Strick MJ, Filan SL, Hile M, et al. Adhesion formation after flexor tendon repair
: a histologic and biomechanical comparison of 2- and 4-strand repairs in a chicken model. J Hand Surg Am. 2004;29:15–21.
30. Lee H, Hou Z, Liu P, et al. An experimental study comparing active mobilization to passive flexion-active extension-active flexion after flexor tendon repair
in zone 2. J Hand Surg Am. 2013;38:672–676.
31. Hast MW, Zuskow A, Soslowsky LJ. The role of animal models in tendon research. Bone Joint Res. 2014;3:193–202.
32. Zhao C, Amadio PC, Tanaka T, et al. Effect on gap size on gliding resistance after flexor tendon repair
. J Bone Joint Surg Am. 2004;86A:2482–2488.
33. Beredjiklian PK. Biologic aspects of flexor tendon laceration and repair: current concepts review. J Bone Joint Surg Am. 2003;85A:539–550.
34. Uslu M, Isik C, Ozsahin M, et al. Flexor tendon repair
: effect of core suture caliber with increased number of suture strands and peripheral sutures: a sheep model. Orthop Traumatol Surg Res. 2014;100:611–616.
35. Diao E, Hariharan JS, Soejima O, et al. Effect of peripheral suture depth on strength of tendon repairs. J Hand Surg Am. 1996;21:234–239.
36. Boyer MI, Gelberman RH, Burns ME, et al. Intrasynovial flexor tendon repair
. an experimental study comparing low and high levels in vivo during rehabilitation in canines. J Bone Joint Surg Am. 2001;83:891–899.
37. Gelberman RH, Boyer MI, Brodt MD, et al. The effect of gap formation
at the repair site on the strength and excursion of intrasynovial flexor tendons. An experimental study on the early stages of tendon-healing in dogs. J Bone Joint Surg Am. 1999;81:975–982.
38. Ejeskär A, Irstam L. Elongation in profundus tendon repair
: a clinical and radiological study. Scand J Plast Reconstr Surg. 1981;15:61–68.
39. Amadio PC. Friction of the gliding surface: implications for tendon surgery and rehabilitation. J Hand Ther. 2005;18:112–119.
40. Amis AASchuind F, An KN, Cooney WP III, Garcia-Elias M. The mechanical properties of finger flexor tendons and development of stronger tendon suturing techniques. Advances in the Biomechanics of the Hand and Wrist. New York: Springer Science+Business Media; 1994:41–57.
41. Kursa K, Lattanza L, Diao E, et al. In vivo flexor tendon forces increase with finger and wrist flexion during active finger flexion and extension. J Orthop Res. 2006;24:763–769.
42. Schuind F, Garcia-Elias M, Cooney WP III, et al. Flexor tendon forces: in vivo measurements. J Hand Surg Am. 1992;17:291–298.
43. Vanhees M, Thoreson AR, Larson DR, et al. The effect of suture preloading on the force to failure and gap formation
after flexor tendon repair
. J Hand Surg Am. 2013;38:56–61.
44. An KNGuilak F, Butler DL, Goldstein SA, Moonet D. In vivo force and strain of tendon, ligament, and capsule. Functional Tissue Engineering. USA: Springer-Verlag; 2003:96–105.
45. Mitsunaga KA, Szabo RMWright HG. What is the best method of rehabilitation after felxor tendon repair
in zone II: passive mobilization of early active motion? What is the best suture configuration for repair of flexor tendon lacerations? Evidence-Based Orthopaedics: The Best Answers to Clinical Questions, 1st ed. Philadelphia: Saunders Elsevier; 2009:91–103.
46. Choueka J, Heminger H, Mass DP. Cyclical testing of zone ii flexor tendon repairs. J Hand Surg Am. 2000;25:1127–1134.
47. Pruitt DL, Manske PR, Fink B. Cyclic stress analysis of flexor tendon repair
. J Hand Surg Am. 1991;16:701–707.