Secure Knot Research Articles

INFLUENCE OF KNOT NUMBER ON HOLDING CAPACITY OF TWO HIGH-STRENGTH SUTURE TAPES: A BIOMECHANICAL ANALYSIS

The number of seven needed knots to provide secure hold of high strength sutures was previously reported. New technologies like tape sutures and sutures with a salt infused silicon core have been developed, potentially reducing the number of needed knots. Study aims: To investigate the influence of (1) throw number and (2) different ambient conditions on knot security in two different high-strength sutures, and (3) to compare their biomechanical competence.Two sutures (SutureTape (FT); n=56 and DynaTape (DT); n=56) were assigned for knot tying. Specimens were exposed to different media during tying, namely air, saline solution, and fat. A monotonic tensile ramp was applied. For each suture and ambient condition, seven specimens with 3 to 7 throws each were tested (n=7), evaluating their slippage and ultimate force to failure. The minimum number of throws preventing suture unraveling was determined in each suture and condition.For each suture type and condition failure occurred via rupturing in all specimens for the following minimum number of throws: FT: dry–6, wet–6, fatty-wet–6; DT: dry–6; wet–4; fatty-wet–5. No significant differences were found comparing ultimate load to rupture of the two groups with minimum number of needed throws in each media. (FT dry-6 vs. DT dry-6; p<0.07); (FT wet-6 vs. DT wet-4; p<0.20); (FT fat-6 vs. DT fat-5; p<0.58). Knot slippage of DT was significantly higher in wet and fatty conditions compared to ST p<0.001 and p<0.004.In fatty-wet conditions DT requires 5 throws to achieve a secure knot. In wet conditions this number can be reduced to 4 throws. FT needs 6 throws to provide a stable knot in all conditions. The biomechanical competence of both sutures in terms of knot slippage and peak force are comparable.

Biomechanical Comparison of Banarji Knot with Various Sliding Locking Knots

Abstract Background: The most essential part of arthroscopic shoulder surgery is tying a secure knot. A knot should be a low profile, nonbulky, and more stable construct. In the present research, we have compared the biomechanical performance of the new sliding locking knot-the Banarji knot, with two different sliding locking knots: The Samsung Medical Centre (SMC) Knot and the Weston Knot. Methods: Two samples of arthroscopic sliding locking knot, Banarji knot with three and five half hitches were taken. They were named Banarji Knots 1 and 2 in the study. The SMC Knot and Weston Knot were taken for comparison with the Banarji Knot. All knots were prepared with high-strength suture material fiber wire (Arthrex, Naples, FL, USA) and were tested in Bose Testing Machine to evaluate the load to failure of knots taken in the research. The statistical significance was determined using a P = 0.05. Results: The maximum load to failure was higher with the Banarji Knot, and it showed significantly better performance when compared with other knots taken in this study. The maximum load to failure in Banarji Knot 1 was 23% and 17% higher than SMC Knot and Weston groups, respectively, and that for Banarji Knot 2 was 29% and 22% higher than SMC and Weston groups, respectively. Conclusion: The Banarji knot is a low-profile, stronger, and stable knot. The biomechanical properties of the Banarji knot were better, and the load to failure was superior to SMC and Weston Knot.

Mulberry Knot Technique for Arthroscopic Meniscus Repair

Background: Meniscus treatment varies on factors such as age of the patient, cause of injury, time since injury, clinical features, site of torn meniscus and financial capacity. The treatment ranges from conservative in form of visco supplements, analgesics and physiotherapy to surgery in form of open or arthroscopic repair or partial menisectomy. We aim to show ten cases of arthroscopic meniscus repair using mulberry knot technique. Material And Methods: Meniscus tear was reduced using probe and long spinal needle. Conventional instruments used were meniscus repair set which includes needle and dart sheath with canula. The repair was done using 2-0 prolene with mulberry knot. Observation And Results: The average follow up period in our study was 3±1.2 months. As per knee society score, we have achieved 80% excellent and 20% good results at 3 months as shown in table 1. We did not encounter any complication in our study as far as intra operative or post operative events are concerned. Discussion: There are different ways and suturing techniques to repair the meniscus. Mulberry knot provides sliding, stable and secured knot formation which is less bulky and more reliable. It has been used frequently to repair rotator cuff in shoulder arthroscopy. It does not cause post operative impingement during movements in rehabilitation process. Conclusion: Mulberry knot technique is unique, stable, secure knot which is done using Prolene 2-0 to be used for meniscus during arthroscopic procedures outside in and inside out repair techniques.

Efficient suturing in herniating adipose with an assistant’s technique of tissue displacement

When suturing surgical defects with exuberant adipose tissue, deep (dermal) sutures often become encased in the adipose tissue, creating an obstruction to approximating the wound edges. In addition, throwing surgeon’s knots can be complicated by binding of the adipose tissue to the suture thread, obstructing a reliably secure knot.1,2 Together, these restrictions slow the efficiency of a repair and may contribute to potential sources of dehiscence.

A new arthroscopic sliding locking knot: Banarji knot

Arthroscopic knot tying is a crucial component for a successful arthroscopic shoulder surgery. Knot tying should not be difficult to master or time consuming to perform. This study describes a new sliding locking knot for arthroscopic shoulder surgery and we named it Banarji knot, in the name of the author. It is a low profile, non-bulky, and double locking knot, which makes it a more secure knot.

What are the skills that represent expert-level laparoscopic suturing? A Delphi Study.

As the field of laparoscopic surgery grows, the need for a valid assessment of laparoscopic surgical skills becomes apparent. The objective of this study was to identify laparoscopic suturing skills reflective of performing at an expert level. A Delphi Study was conducted with expert laparoscopic surgeons. Tasks were considered to meet criteria for consensus after 80% of survey participants answered "strongly agree." Results of the previous round of surveys were shared with participants at the start of the next round. The predefined endpoint for the Delphi was set as maximum of three rounds, reaching 80% consensus on each skill, or if > 50% of initial respondents fail to return for subsequent surveys. After three rounds of surveys completed by 13 advanced laparoscopic surgeons, 8 observed skills met consensus (> 80% selected "strongly agree"): forehand suturing, continuous suturing, avoiding tissue trauma, achieving a technically acceptable final product (tight closure), tying a secure knot at the end of suturing, maintaining/checking for appropriate tightness of running suture, accurate depth perception, and loading the needle in < 3 attempts. Skills that approached consensus (with > 50% ranking them as "strongly agree") included correct penetration of target tissue, ability to create a surgeon's knot, awareness of needle tip position, confined space suturing, following the curve of the needle, smooth movements of instruments, loading the needle correctly, adjusting for tissue thickness, and bimanual dexterity. Using Delphi methodology, we identified the skills that are representative of expert laparoscopic suturing. This information can be used to create an assessment tool for this domain. Validation of such a tool will help advance the surgical field towards true competency-based assessment of expertise.

Endoscopic robotic suturing: The way forward.

Traditionally, suturing is performed in open surgery using a needle holder and forceps. The aim is to achieve accurate approximation of both edges of the wound and to tie a secure knot. With the development of laparoscopic surgery, traditional suturing methods have been adapted to meet the constraints of rigid laparoscopic instruments with limited degrees of freedom. The subsequent introduction of three-dimensional robotic suturing has since made intracorporeal suturing easier to learn, primarily because of its intuitiveness and the additional degree of freedom of the robotic wrists. With the increasing popularity of therapeutic endoscopic procedures for early gastrointestinal cancers, devices allowing for endoscopic suturing have since been developed. Nevertheless, these devices remain challenging to use as they require double-channel endoscopes and do not have the extra degree of freedom of robotic wrists. The introduction of robotics to the field of endoscopic suturing has proven to be promising. This review describes the development and adaptation of basic suturing techniques to various platforms, such as laparoscopic, robotic and endoscopic.

In vitro security of 3 surgical knots placed by novice veterinary students.

To determine the most secure knot when tied by veterinary students in a ligation model. Prospective study. Sixteen first-year veterinary students. Veterinary students were taught 3 knots: surgeon's, Miller's, and strangle. After having demonstrated competence, students tied each knot twice in a vascular ligation model at physiologic pressure. The system was tested for completeness of occlusion and volume of fluid lost over 10 seconds. Time, reattempts, repositioning, correctness, and difficulty score were documented. Students were surveyed before and after training regarding their experience. Students correctly tied 75% of all knots and achieved complete occlusion of the model with 56% of knots. No difference was identified among knot types in correctness, difficulty, complete occlusion, or time to construct the knot. The first surgeon's knot placed by students had more fluid loss than the Miller's knot, but this was not true of the second knot. Incomplete occlusion was common among all knot types, but students generally achieved similar knot security when placing surgeon's, Miller's, and strangle knots on a model. More surgeon's knots failed catastrophically during the first attempt, evidenced by a greater volume of fluid loss. This study does not provide evidence to recommend any of the 3 tested knots as superior to the others to improve the security of ligatures during surgeries performed by students. The prevalence of incomplete occlusion among student knots illustrates the requirement for education regarding knot security and vigilant monitoring of students performing live animal surgeries.

Integral Suture-Handling Techniques for Arthroscopic Sliding Knots

In arthroscopic tissue repair, the final step is achieving adequate tissue approximation with a secure knot. The sliding knot is widely preferred over the nonsliding knot, with numerous publications describing knot configurations. However, in the literature there are few published descriptions of suture-handling techniques, even though they are fundamental to arthroscopic knot tying. We describe integral suture-handling techniques for arthroscopic sliding knots to improve the surgeon's performance in knot tying.

A study of slippage of various knot configurations

Penetrating keratoplasty (PK) still remains the predominant procedure in corneal graft surgery. Complications include wound dehiscence, immune-mediated rejection, and refractive errors.1 A study by Jeganathan et al2 showed that resuturing of corneal wounds after PK may be required for various reasons, including wound dehiscence, loose sutures, and infectious keratitis, which can increase the incidence and severity of complications many fold.2, 3 There is evidence that inflammatory response and adhesion formation surrounding the sutures are most pronounced at the site of the knot.4, 5 Three different knots, 3/1/1, 1/1/1(slip-knot), and 1/1/1/1(modified slip-knot), were compared using 10-0 black monofilament polyamide-6 suture (Ethilon 30 cm with a 6-mm micro-point spatula needle, Johnson & Johnson, New Brunswick, NJ, USA). A special apparatus was designed for the study (Figure 1). The horizontal and vertical sizes of the knots and slippage were measured with a calibrated eyepiece graticule using a Nikon-E51i binocular bright-field microscope (New York, NY, USA). Knot slippage was observed at 5 and 24 h. The study was repeated five times for each knot type. Knot morphology was observed using a scanning electron microscope (Figure 2). Figure 1 Schematic diagram of the knot under study. Figure 2 (a) (Left): Scanning electron microscope image of 3/1/1 knot (100 μm); (b) (middle): scanning electron microscope of knot 1/1/1/1 (100 μm); (c) (right): scanning electron microscope image of 1/1/1 (100 μ ... Using a tension weight of 10 g, the mean slippage of knots measured at 5 and 24 h was least with 3/1/1 and maximum with 1/1/1 (Figure 3a). Using a tension weight of 20 g the mean slippage of knots at 5 h was least with 3/1/1 and maximum with 1/1/1/1, while at 24 h it was equal with 1/1/1 and 1/1/1/1 (Figure 3b). The knot size was measured in vertical and horizontal axes to the suture line. The 3/1/1 knot was found to be the largest (Figure 3c). There was no significant difference seen in the size of 1/1/1 and 1/1/1/1 knot. Figure 3 (a) Knot slippage with 10-g weight (top left: mean slippage at 5 h; top right: mean slippage at 24 h). (b) Knot slippage with 20-g weight (middle left: mean slippage at 5 h; middle right: mean slippage at 24 h). (c) Average ... Paired t test was used for statistical analysis (Data analysis toolpak, SPSS, Chicago, CA, USA) (Table 1). Table 1 Statistical values of paired t tests used to compare knots In conclusion, our study demonstrates that 3/1/1 is the most secure knot with least slippage but was the largest of the three knots. The 1/1/1 knot showed the most slippage. The 1/1/1/1 knot may be a better knot type with benefits of minimum slippage and a smaller knot size, making it easy to bury.

The Effect on Loop Elongation and Stress Relaxation During Longitudinal Loading of FiberWire in Shoulder Arthroscopic Knots

This study examined the viscoelastic properties of 6 common arthroscopic sliding knots (Tennessee slider, Roeder knot, SMC knot, Duncan loop, Weston knot, and Nicky's knot) with 3 reversing half-hitches on alternating posts, tied with No. 2 FiberWire (Arthrex, Naples, FL). Knot configuration was designed to simulate a double-row rotator cuff repair with suture bridges. Constructs were loaded in 20-N increments to 100 N and held for 2 minutes to monitor the viscoelastic behavior in tension. Suture was also tested without tying a knot. Stress relaxation increased with loading but did not differ between knot configurations. Initial elongation was highest during the first loading to 20 N. Relaxation was greater for the Roeder knot at 20 N and for the Roeder and SMC knots at 80 N (P < .05) when compared with the loop with no knot. Elongation was greatest for the Roeder knot throughout all loads. This difference was significant at 60 N compared with the knotless loop. At 100 N, all knots showed greater elongation than the knotless loop (P < .05). Testing of suture, without any knots, accounted for more than 75% of the overall stress relaxation and loop elongation of the suture-knot construct. In our in vitro evaluation of the Tennessee slider, Roeder knot, SMC knot, Duncan loop, Weston knot, and Nicky's knot in a simulated suture bridge construct, knot configuration was not a variable that influenced elongation or stress relaxation. Overall response was primarily due to the suture itself. With the exception of the Roeder knot, relaxation was similar provided that a secure knot was formed at the time of original tying. With the evolution of surgical devices, the reliance on knots is decreasing. The results of this study suggest that using knotless techniques for securing the rotator cuff will not change the stress relaxation characteristics of the suture bridge.

Standardization is superior to traditional methods of teaching open vascular simulation

Standardizing surgical skills teaching has been proposed as a method to rapidly attain technical competence. This study compared acquisition of vascular skills by standardized vs traditional teaching methods. The study randomized 18 first-year surgical residents to a standardized or traditional group. Participants were taught technical aspects of vascular anastomosis using femoral anastomosis simulation (Limbs & Things, Savannah, Ga), supplemented with factual information. One expert instructor taught a standardized anastomosis technique using the same method each time to one group over four sessions, while, similar to current vascular training, four different expert instructors each taught one session to the other (traditional) group. Knowledge and technical skill were assessed at study completion by an independent vascular expert using Objective Structured Assessment of Technical Skill (OSATS) performance metrics. Participants also provided a written evaluation of the study experience. The standardized group had significantly higher mean overall technical (95.7% vs 75.8%; P = .038) and global skill scores (83.4% vs 67%; P = .006). Tissue handling, efficiency of motion, overall technical skill, and flow of operation were rated significantly higher in the standardized group (mean range, 88%-96% vs 67.6%-77.6%; P < .05). The standardized group trended to better cognitive knowledge (mean, 68.8% vs 60.7%; P = .182), creation of a secure knot at the toe of the anastomosis, fashioning an appropriate arteriotomy, better double-ended suture placement at the heel of the anastomosis (100% vs 62.7%; P = .07), and accurate suture placement (70% vs 25%; P = .153). Seventy-two percent of participant evaluations suggested a preference for a standardized approach. This study demonstrates the feasibility of open vascular simulation to assess the effect of differing teaching methods on performance outcome. Findings from this report suggest that for simulation training, standardized may be more effective than traditional methods of teaching. Transferability of simulator-acquired skills to the clinical setting will be required before open simulation can be unequivocally recommended as a major component of resident technical skill training.

A secure Aberdeen knot: in vitro assessment of knot security in plasma and fat

To determine the minimum number of throws/turns to form a secure Aberdeen knot and the maximum ear slippage for these knots using three metric polydioxanone coated in fat or plasma. To compare plasma and novel canine liquefied fat as suture coating mediums for in vitro knot security testing. Throws/turns were incrementally added until a secure knot was found for plasma and fat. Knots were tensioned until failure and remaining ear length measured. A secure knot was defined as ear slippage 3 mm or less in 20 consecutively tested knots. Ear slippages were statistically analysed. Minimum secure configuration was a 3+1 knot in plasma and fat, and its ear slipped a maximum of 2 mm in plasma and 2.5 mm in fat. A secure 4+1 knot had a maximum ear slippage of 0.5 mm, which was significantly less than that of the 3+1 knot (P<0.0001). Fat coating suture significantly decreases in vitro knot security compared with plasma (P=0.0035). The novel fat coating medium should be considered when testing in vitro knot security as it simulates a clinical knot tying environment. A 4+1 Aberdeen knot with a 3 mm ear is recommended to tie a secure Aberdeen knot in any body fluid environment.

Technical Notes and Tips: DIY Surgical Knot-Tying Tool

The ability to tie a safe, secure knot is one the first and most fundamental skills that a surgeon learns. Traditional simulators that are used by trainee surgeons to practise knot tying are based around a fixed hook attached to a surface or attached inside of a cup to simulate knot tying down into the pelvis. It has been suggested that the more junior a trainee surgeon is the more force they apply to the structure being tied. In vivo, this can result in problems like vessel avulsion. This simple DIY technique allows a trainee surgeon to practise knot tying whilst also practising the skill of not applying too much force to the structure being suture ligated, something that can not be practised on a fixed hook simulator. An empty 330-ml drink can is needed. The ring pull is positioned upright as illustrated (Fig. 1). The can is placed on a piece of A4 paper and a circle drawn around the side of the can. The trainee then uses the ring pull to practise tying knots without moving the can outside of the circle or lifting the can from the surface. This provides for a cheap, simple and readily available training tool. Figure 1 Illustration of the technique.

Robotic-assisted laparoscopic cerclage in a pregnant patient

A robotic-assisted laparoscopic technique for transabdominal cerclage placement could offer improvements over the traditional laparoscopic approach. A gravid female with no vaginal portion of the cervix underwent a robotic-assisted laparoscopic cerclage at 12 weeks' gestation and ultimately delivered a healthy infant at term.

Material and knot properties of braided polyester (Ticron®) and bioabsorbable poly-L/D-lactide (PLDLA) 96/4 sutures

The purpose of the present study was to investigate in vitro the biomechanical material and knot properties and histomorphometrical knot properties of 3-0 braided polyester suture (Ticron) and bioabsorbable poly-L/D-lactide (PLDLA) 96/4 suture. In Ticron five throws are needed to form a secure knot, and the 1 = 1 = 1 = 1 = 1 and the 2 = 1 = 1 = 1 configurations are recommended. For PLDLA several granny and square knots formed a secure knot, but the 1 = 1 and 1 = 1 = 1 knots were the best. These PLDLA knots had lower yield force and strain at yield point, but higher stiffness than the recommended Ticron knots. The ultimate force values did not differ, but PLDLA knots had significantly higher strain at ultimate point. In the histomorphometrical analysis of the recommended knots, the PLDLA knots had a significantly smaller knot surface area than the Ticron knots. According to these results, PLDLA suture proved to be suitable for flexor tendon repair.

The Triad Knot: A New Sliding Self-Locking Knot

Tying secure knots is essential in arthroscopic surgery. A new slip knot for arthroscopic shoulder surgery is described. Locking of the knot is accomplished by pulling the post strand. Knot tying is simple and a low-profile, secure knot is produced.

Assessment of knot security in continuous intradermal wound closures

The traditionally used square knot used for commencement and termination of continuous wound closures is bulky, requiring a minimum of four to six throws to form a secure knot with most suture materials and sizes. This study evaluates the security of self-locking knots, which are significantly smaller in volume than the traditionally applied square knot, for the intradermal closure of standardized wounds in porcine skin. Porcine skin samples with standardized wounds were closed in one of five patterns with 3/0 PDS suture. Wounds were harvested and tested to failure on a materials testing machine. Load at failure, ultimate elongation, wound stiffness, and mode of failure was determined for each sample. Wound closures incorporating the chain stitch knot performed as well as closures incorporating the conventional square knot for load to failure, elongation, and stiffness. Partial slippage or complete knot failure of 4/40 (10%) of the square knots used in closures was observed. 0/20 (0%) of the chain stitch knots displayed slippage. The half-blood knot performed similarly to the square and chain stitch knot in load to failure, elongation, and stiffness, however, 16/20 (80%) of these knots displayed slippage or complete knot failure. The chain stitch knot is as secure as the traditionally used square knot when used for termination of a continuous intradermal wound closure. This knot displays characteristics such as smaller knot volume and ease of applications that may make it a superior knot to the square knot in many clinical situations.

In vitro evaluation of fluorocarbon leader line for use as a fabella-tibial suture

SummaryCranial cruciate ligament rupture is a common injury in dogs, for which a variety of surgical techniques have been described. A commonly performed surgical technique is extracapsular stabilization with a lateral fabella-tibial suture (LFS) using large diameter nylon leader line (NLL). Inherent properties of NLL such as memory, low coefficient of friction, and large diameter may compromise knot security. Fluorocarbon (polyvinylidene fluoride; PVDF) has been investigated as a biomaterial for a variety of implants and is available as a high tensile strength fluorocarbon leader line (FCL). For a given tensile strength FCL is one-half the diameter of NLL. This study evaluated the force at failure, elongation, and stiffness of FCL compared to NLL for use as a LFS. The effects of steam and ethylene oxide sterilization on FCL were also evaluated. The results of this study demonstrate similar force at failure and stiffness for FCL when compared to NLL. In addition, the use of FCL may eliminate the elongation under low load observed with NLL. The mechanical properties of FCL loops were not affected by ethylene oxide sterilization. In contrast, steam sterilization caused significant detrimental effects on the mechanical properties of FCL and is not recommended. The reduced diameter and pliable feel of FCL allow for superior handling, formation of a less bulky and potentially more secure knot, and less foreign material in the region of implantation. FCL appears to be a suitable alternative material to NLL for a lateral fabella-tibial suture.

Newly devised anterior portal technique for arthroscopic bankart repair using suture anchors

Many techniques and instrument systems have been developed for performing arthroscopic Bankart repair using a suture anchor. The suture anchor procedure relies on a secure knot, which does not become entangled in the anterior portal. A newly devised anterior portal technique can solve this problem. We have used this technique for arthroscopic Bankart repair using suture anchor. This technique may be useful for any type of suture materials such as SLAP lesion.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 3 (March), 2002: pp 329–331