Prevention of knot slippage with the use of cyanoacrylate glue: a mechanical study

Arthroscopic knots: Suture and knot characterisation of modern polyblend suture materials

Objective

The primary aim of this study was to explore the relationship between the biophysical structure and function of modern suture materials. Particularly the suture's ability to withstand the stressors of surgery and how the material properties affect knot stability. The secondary aim was to investigate the effect that different knots have on the suture material itself. This study builds on previous research assessing suture and knot characteristics but in modern Ultra High Molecular Weight Polyethylene (UHMWPE) materials currently in widespread clinical use in arthroscopic surgery.

Methods

Three common UHMWPE sutures and one polyester suture were tested in both a dry and wet state using the Geelong, Nicky's, Surgeon's and Tautline knots. Tensile strength of knots was tested vertically at a 60 mm/min strain rate and 45 mm gauge length. Sutures were tied through a cannula around two 8 mm diameter circular bollards. Testing was conducted in a controlled environment temperature and humidity environment (20 ± 2 °C, 65 ± 2%).

Results

No one knot type was optimal over all suture types. Mean tensile strength in both a dry and wet state and a low coefficient of variation (CV) in tensile strength in a wet state were considered as an indication of suitability. With Ethibond sutures this was the Geelong knot (CV:4.2%). With Orthocord sutures both the Geelong and Tautline knots (CV:4.2% and CV:11.9% respectively). With FiberWire sutures the Nickys and Tautline knots (CV:22.6% and CV:22.5% respectively). With ForceFiber sutures all four knots exhibited similar wet tensile strength with high variability showing that all should perform in a similar way invivo.

Conclusions

This study demonstrates a statistically significant three-way interaction between polyblend suture materials, the knot and the environment. This has implications for knot security using the tested sutures in different environments, as one knot may not behave the same under all conditions.

The effect of cyanoacrylate on knot elongation in three sutures used for prosthetic laryngoplasty in the horse

OBJECTIVE

This study investigated the elongation following cyclic loading on square knots of 5 USP multifilament long-chain ultra-high molecular weight polyethylene core (UHMWPE), 2 mm woven UHMWPE tape, and 5 USP braided polyester, with and without cyanoacrylate glue.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

n = 4.

METHODS

Three conditions (suture without knot, suture with knot, suture with knot + cyanoacrylate) were evaluated for each suture material on a mechanical test stand by measuring the increased length of the construct after cycling from 25 to 50N for 1000 repetitions at 20 mm/second. Knot elongation was determined by subtracting the length of the control suture from the suture with knot or suture with knot + cyanoacrylate. The data were analyzed with a linear regression model with robust estimation of variance. Post-hoc analysis determined the model adjusted differences (square knot vs. cyanoacrylate) as a difference from control. t-tests were conducted to identify the significant findings.

RESULTS

Total elongation of polyester (6.2-7.8 mm) was greater than multifilament UHMWPE (3.4-6.4 mm) and UHMWPE tape (2-3.7 mm) for all conditions. Polyester had the lowest knot elongation (1.6 mm) and the addition of cyanoacrylate decreased knot elongation for polyester by 1 mm.

CONCLUSIONS

Polyester had the most total construct elongation followed by multifilament UHMWPE and UHMWPE tape. Polyester showed the least knot elongation and cyanoacrylate decreased this knot elongation.

CLINICAL SIGNIFICANCE

Total construct and knot elongation should be considered as contributing factors to loss of arytenoid abduction following prosthetic laryngoplasty when using polyester, multifilament UHMWPE, or UHMWPE tape. Addition of cyanoacrylate to polyester knots should be explored to limit elongation.

Advances in carbohydrate-based polymers for the design of suture materials: A review

Suture materials constitute one of the largest biomedical material groups with a huge global market of $ 1.3 billion annually and employment in over 12 million procedures per year. Suture materials have radically evolved over the years, from basic strips of linen to more advanced synthetic polymer sutures. Yet, the journey to the ideal suture material is far from over and we now stand on the brink of a new era of improved suture materials with greater safety and efficacy. This next step in the evolutionary timeline of suture materials, involves the use of natural, carbohydrate polymers that have, until recent years, never before been considered for suture material applications. This review exposes the latest and most important advancements in suture material development while digging deep into how natural, carbohydrate polymers can serve to advance this field.

Compression properties and dissolution of bioactive glass S53P4 and n-butyl-2 cyanoacrylate tissue adhesive-composite

Bioactive glass (BG)-containing fiber-reinforced composite implants, typically screw-retained, have started to be used clinically. In this study, we tested the mechanical strength of composites formed by a potential implant adhesive of n-butyl-2-cyanoacrylate glue and BG S53P4 particles. Water immersion for 3, 10 or 30 days had no adverse effect on the compression strength. When cyanoacrylate glue-BG-composites were subjected to simulated body fluid immersion, the average pH rose to 7.52 (SD 0.066) from the original value of 7.35 after 7 days, and this pH increment was smaller compared to BG particle-group or fibrin glue-BG-composite group. Based on these results n-butyl-2 cyanoacrylate glue, by potentially producing a strong adhesion, might be considered a possible alternative for fixation of BG S53P4 containing composite implants. However, the mechanical and solubility properties of the cyanoacrylate glue may not encourage the use of this tissue adhesive with BG particles.

Causes of Flexor Tendon Repair Failures in Two Common Repair Techniques: A Cadaver Study

BACKGROUND

Flexor tendon repair failures have primarily been attributed to either core suture rupture or core suture pull out. Recent studies have suggested that knot unravelling may also cause failure of a tendon repair. The aim of this study was to investigate the causes of core suture failure in two types of common flexor tendon repairs.

METHODS

Twenty four cadaver tendons were divided into three groups of eight. Each group tested a specific flexor tendon repair. The repairs tested included an Adelaide repair using 4/0 Ethibond (Ethicon), an Adelaide repair using 4/0 Fiberwire (Arthrex) and the Tsai repair with 4/0 Fiberloop (Arthrex). The repaired tendons were pull-tested to failure. The mechanism of failure, maximum tensile strength and 2 mm gap force were recorded.

RESULTS

The predominant mode of failure was by the knot unravelling. This occurred in 50-88% of the tendon repairs. The sequence of failure was initiated with gapping at the repair site followed by failure of the epitendinous suture. Next the core suture knot unravels. Once the knot unravels, the suture thread slips out of the tendon resulting in the repair failure. Failures due to knot slippage occurred at a lower maximum tensile strength in Ethibond and Fiberloop sutures than failure due to core rupture or pull out. However, given the small number of tendons tested, this result was not significant.

CONCLUSIONS

This study has clearly demonstrated one of the main causes of flexor tendon repair failure in two common repair techniques is knot unravelling.