title: [Biomechanical investigation of the tensile strength of tendon sutures - locking sutures increase stability].
abstract: OBJECTIVE
  In this study we examined the tensile strength of core sutures of tendons. In particular, we examined the effect of having 2 or 4 stitch strands in the core suture as well as the effect of additional locking sutures on the tensile strength.
  
  
  METHODS
  60 flexor tendons from the forepaws of freshly slaughtered swines were harvested for biomechanical testing. They were divided into 4 groups (A, B, C and D) of 15 sutures each. Group A: core suture after Zechner with 2 strands; group B: modified core suture with 4 strands; group C: modified core suture with 2 strands and 4 locking sutures; group D: modified core suture with 4 strands and 4 locking sutures. The primary tensile strength of the sutures was measured in Newton using the testing machine with a traction speed of 0.1 mm/s. Simultaneously, the increasing space forming at the suture was filmed against graph paper. Our command variables were force measured in Newton when forming a space of 2 mm as well as the force at which the suture failed. Statistical analysis was carried out with the software SPSS to produce a multivariate analysis with a statistical significance of p<0.05.
  
  
  RESULTS
  Results are presented as averages including the 1st and 3rd quartile (1Q/3Q). Under traction to form a 2 mm space, the force measured with group A was 14.2 N (12.9/15.1 N). In group B the force 22.5 N (20.0/24.7 N) was significantly higher (p<0.05). Group C required a traction force of 28.7 N (23.5/35.8 N) which was significantly higher than for groups A and B. Group D required the significantly highest traction force of 42.0 N (39.5/46.0 N) to produce a 2 mm space. The force required for the suture to fail in group A was 19.9 N (17.9/22.8 N), in group B: 26.2 N (24.5/29.7 N), in group C 32.0 N (27.1/40.1 N) and in Group D 46.5 N (41.5/50.0 N); the differences between the gloups were all statistically significant.
  
  
  CONCLUSIONS
  The primary tensile strength of core sutures after Zechner on flexor tendons from the forepaws of swines was significantly increased by doubling the number of sutures and also by use of 4 additional locking sutures.
authors.affiliation: Berufsgenossenschaftliche Unfallklinik Frankfurt am Main, Unfallchirurgie und Orthopädische Chirurgie, Frankfurt. christian.betz@bgu-frankfurt.de
authors.forename: C
authors.initials: C
authors.lastname: Betz
authors.forename: P
authors.initials: P
authors.lastname: Schleicher
authors.forename: R
authors.initials: R
authors.lastname: Winkel
authors.forename: R
authors.initials: R
authors.lastname: Hoffmann
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D006801:Humans; D008432:Mathematical Computing; D013536:Suture Techniques; D013552:Swine; D013718:Tensile Strength / Q000502:physiology*; D014143:Traction; D014741:Video Recording