Effect of Manufacturing Conditions on Structural and Handling Properties of Braided Polyamide Suture
Suture performances include handling characteristics and knot mechanical properties. These performances depend mainly on frictional, flexural, and compressive forces. The interaction between these forces developed inside the suture knot governs the displacement mode and the deformability of the suture yarn inside the knot. In the present work, we studied the effect of manufacturing conditions on structural properties and handling characteristics. Obtained results show that manufacturing parameters have significant impact on slipperiness, flexibility, and compressibility. Consequently, suture performances widely depend on manufacturing parameters. We show that after a hot stretch step, suture structure becomes more uniform and compact. Furthermore, after this treatment, lateral deformation, friction force, and bending rigidity are reduced and knot performances are improved.
Impact of hot-stretching treatment on physical and mechanical properties of braided polyamide suture
Suture is the most used implant in the human body, but it is not yet perfect. Braided polyamide sutures have to undergo several manufacturing steps, including hot-stretching. The main objective of this work was to analyze physical structural changes of polyamide fibers after the hot-stretching step and to highlight mechanical property changes related to this treatment. The obtained results showed that hot-stretching of polyamide braided suture allows one to obtain uniform and compact suture. In this paper, modification of mechanical properties due to hot-stretching has been correlated to macromolecular properties, such as crystallinity, crystal size and macromolecular chain orientation. Hot-stretching braided suture at a temperature higher than 200℃ and the medium value of drawing ratio resulted in the best braided suture properties. Below 180℃, polyamide braided suture undergoes thermal shrinkage during hot-stretching, leading to an increase in breaking extension. Hot-stretching suture ameliorated fabricated braided suture crystallinity reached 33%, with the creation of numerous crystals with smaller size. Using an overlaid contours plot, we have determined optimal values for significant manufacturing parameters in order to manufacture polyamide braided suture that has high ultimate tensile strength, low extension at break, low rigidity and high crystallinity.
Biomechanical characteristics of 10 arthroscopic knots.
PURPOSE
To determine the optimal arthroscopic slip knot through comparison of ease of placement, loop security, knot security, and amount of suture material needed.


METHODS
Ten commonly used arthroscopic knots (Dines knot, Duncan loop, Field knot, Giant knot, Lieurance Modified Roeder knot, Nicky's knot, SMC knot, Snyder knot, Tennessee slider, Weston knot) were tested. Ten knots were tied with No. 2 Ethibond (Ethicon, Somerville, NJ) for each testing mode trial. Each knot was tested with the Instron materials testing machine (Instron, Norwood, MA) for (1) forward and backward sliding characteristics; (2) loop security prior to securing with half-hitches (by assessing load); (3) resistance to sliding; (4) knot security after securing with 3 alternating half-hitches on alternating posts (by assessing ultimate load); (5) resistance to sliding; (6) distance to failure; and (7) knot weight, to evaluate for amount of suture material needed. Analysis of variance (P < .05) was used to compare different knots, and the knot with superior characteristics in most categories was selected as the best knot.


RESULTS
The Dines knot performed best, exhibiting superior biomechanical characteristics in 6 of 7 measured categories. The only category in which the Dines knot did not perform superiorly was forward sliding, indicating that the Dines knot can be rated as intermediate in ease of placement.


CONCLUSIONS
Once in place, the Dines knot provides superior loop security and knot security, with use of less suture material.


CLINICAL SIGNIFICANCE
This study comprehensively analyzed 10 commonly used arthroscopic knots and identified the one that exhibited the best characteristics.