1、Arthroscopic knot typing a instruction Manual 1 An increasing number of surgeons are performing arthroscopic surgery in the knee to repair meniscal tears and in the shoulder to repair rotator cuff or labral tears Many are also performing capsular shifts to treat instability.Essential to these proced
2、ures is the ability to tie arthroscopic knots to approximate intraarticularIntroduction2 The surgeon must sequentially construct the knot outside the joint and then pass the knot into the joint through small cannulas Tying arthroscopic knots is technically demanding and requires considerable practic
3、e With the popularity of arthroscopic surgery,the number of used arthroscopic knots and the number of surgeons using these knots has increased3Knot Tying Principles The goal of knot tying is to approximate tissue under tension and maintain the tissue in apposition until biologic repair and healing c
4、an occur It is imperative for all surgeons to learn and use knot-tying techniques that minimize the chance of knot failure4 Knot security friction,internal interference,and slack between throws Friction is inherent to the suture material Internal interference the configuration of the knot and increa
5、sed by the length of the contact between the loop limb and the post limb slack between the individual throws in each knot to maximize loop security slippage can lead to failure of tissue appositionKnot Tying Principles5four different processes of knot failure knot slippage and looseningsuture breaka
6、getissue failuresuture anchor pullout from bonethrough suture breakageKnot failure 6Knot Terminology post limb(also commonly known as the axial limb)loop limb(also commonly known as the wrapping limb,working end,running end,or free end)Knots are constructed by tying the loop limb around the post lim
7、b(Fig.1)7FIGURE 1.Loop and post configuration 8Arthroscopic Knot Pushers An arthroscopic knot pusher is a device used to advance the loop down the post limb into the joint to create the knot.Arthrex knot pushers.A.Single-hole,B.Double-hole,C.6th Finger 9FIGURE 3.Mitek knot pushers.A.Single-hole,B.Do
8、uble-hole,C.Slotted 10double-hole knot pushers and double diameter knot double-hole knot pushers and double diameter knot pushers like the Arthrex 6th Finger(Arthrex,Naples,FL).Double-diameter knot pushers provide better loop security compared to standard single-hole knot pushers11Double-hole knot p
9、usherFIGURE 4.Double-hole knot pusher.12How to Use the Double-Diameter Knot Pusher FIGURE 5.A-F.Tying knots with the Arthrex 6th finger 13Suture Properties Two types of sutures are commonly used in tying arthroscopic knots:a permanent,braided,polyester,nonabsorbable suture and an absorbable,monofila
10、ment suture Examples of permanent,braided,polyester,nonabsorbable sutures are Ethibond and Ticron Examples of absorbable,monofilament sutures are PDS II,polydiaxonone and Maxon,polyglyconate 14 Braided polyester has increased pliability,ductility,a higher coefficient of friction and greater strength
11、 than does absorbable monofilament Because the braided suture is more pliable,the volume of the knot is decreased and these knots can be cinched tighter.Knots tied with Ethibond were shown to be stronger when compared to PDS II in several biomechanical studies However,braided polyester may fray with
12、 excessive handling,which may lead to suture rupture15Braided polyester suture may be coated to:improve surgeon handling reduce friction between the suture and surrounding tissue,which can lead the tissue damagedecrease friction between suture limbs,which may lead to frayingHowever,suture coating de
13、creases the coefficient of friction of the knot,which theoretically increases the risk of knot slippage16 Knots tied with absorbable,monofilament sutures are easier to slide down a post and do not fray There is less friction between the suture and surrounding tissue leading to less potential tissue
14、damage when the suture is pulled through the tissue absorbable sutures dissolve and do not leave knots that may cause a persistent inflammatory reaction after tissue healing Absorbable sutures can appose tissue under stress for approximately six weeks with complete absorption occurring in approximat
15、ely six months 17 However,absorbable monofilament sutures are harder to handle than polyester making it more difficult to keep knots tight and secure Also,a absorbable monofilament suture will fail earlier with cyclic loading than polyester suture and may expand by plastic deformation more than 30%o
16、f its length before breaking 18 The size of the suture is also a factor in determining a knots holding capacity and also the tensile strength of the suture itself Clinical failure of all knots and suture types improved by 100%when suture size was increased by 2 gauges USP(U.S.Pharmacopeia.The size s
17、uture most commonly used in arthroscopic surgery is No.1 or No.2.19Knot Types There are a variety of knot include nonsliding knots,sliding knots,and locking knots.Nonsliding knots are knots that do not slide though the tissues being apposed.They include the square knot and knots consisting of a seri
18、es of half hitches like the Revo knot(34)Although the square knot fails at higher loads than do series of half hitches in hand-tied knots(38),the square knot is not commonly used arthroscopically.20 The square knot is a flat knot in which both strands enter and leave the knot parallel to each other(
19、Fig.6).In order to tie a square knot,symmetric tension must be simultaneously applied to each limb,which is difficult to do arthroscopically If asymmetric tension is applied to one of the limbs,the knot converts to two nonidentical half hitches Thus,most arthroscopic surgeons prefer using a series o
20、f half hitches21FIGURE 6.Square knot configuration.22 Sliding knots,like the Duncan loop(27),are useful in opposing tissue under tension.While tying a sliding knot,the post strand is held under tension while the loop strand is tied around it.Because the post strand is not incorporated into the struc
21、ture of the knot,the knot,once tied,can easily move down the post resulting in a sliding knot instead of a flat knot such as the square knot.Once the sliding knots are seated,they are often locked with a series of half hitches.Some sliding knots preferentially slide in only one direction23A locking
22、knot is a modification of a sliding knot A simple sliding knot can loosen before a series of half hitches are thrown to“lock”the sliding knot in placelocking knots(also known as flip knots)have been developed to maintain initial loop security that does not loosen when tension is removedThe post stra
23、nd“flips,”converting the loop strand into the new post strand and locking the knot into place.An example of a locking knot is the SMC knot.locking knots do not need to be supplemented with a series of half hitchesThe authors of this manual have found locking knots without reinforcing half hitches to
24、 be inferior in tensile strength to knots reinforced with three reversed half hitches on alternating posts(unpublished data)24Locking and sliding knots can be advanced into the joint just by pulling on the post.This can cause tension at the repair site,which can damage the tissue being apposed.Tensi
25、on at the repair site can be minimized by pushing the knot ahead with the knot pusher while simultaneously pulling on the post limb.With locking and sliding knots,it is important that the loop limb is at least twice as long as the post limb.If it is not,when pulling the post limb to advance the knot
26、 through the cannula and into the joint,the shortened loop limb may be pulled into the cannula making it impossible to secure the knot.When using a sliding or locking knot configuration,it is important to ensure that the suture slides easily through the tissue being opposed.If the suture does not sl
27、ide easily,the surgeon should consider using a nonsliding knot.25Knot Pushing and Pulling Knot configurations can be either pushed or pulled into the joint.he arthroscopic knot-tying device is positioned on the loop limb and is advanced past the half hitch thus pulling the loop over the post limb in
28、to the joint(Fig.7A).The arthroscopic knot-tying device is positioned on the post limb behind the knot thus pushing the loop over the post limb into the joint(Fig.7B).26FIGURE 7.A.Knot pulling,B.Knot pushing.27Tying Half Hitches Using the one hand knot-tying technique,half hitches can be tied either
29、 underhand or overhand The following instructions define an underhand loop and an overhand loop28FIGURE 8.A-E.Underhand half hitch.2930Configuration of Half Hitches Half hitches can be thrown in the same direction(two successive overhand hitches)or can be thrown in opposite directions(an overhand hi
30、tch followed by an underhand hitch)Half hitches can also be tied on opposite posts.Tera and Aberg(37)developed a nomenclature for describing flat knots.31Post SwitchingFIGURE 13.A.Parallel loop and post limbs.B.Parallel loop and post limbs with a“flat”knot.32FIGURE 14.A.Twisted loop and post limbs.B
31、.When tying a knot with twisted post and loop limbs,the knot does not lie“flat.”C.The final knot configuration will loosen if the knot is tied when the loop and post limbs are twisted.33 Chan and Burkhart described a may increase the speed of the knot-tying process and also help limit twisting of th
32、e suture limbs.One can“flip”a half hitch by releasing tension on the post limb and pulling on the loop limb.When the post is switched,the direction of the half hitch is also reversed.The authors of this technique report that it is easier to flip half hitches using monofilament because it more readil
33、y converts to a flat knot,but it can also be done with braided suture.34 Hold the post in the nondominant hand and the loop in the dominant hand(Fig.15A).Move the original post forward and ahead of the half hitch.Apply parallel traction on the post and loop simultaneously converting the half hitch t
34、o a flat knot(Fig.15B).Apply axial traction to the loop limb converting it into the new post limb and the half hitch is reversed(Fig.15C).35Post Switching Technique FIGURE 15.A-C.Post switching technique 36Arthroscopic Knot-Tying TechniquesIt is important to determine if the suture slides through th
35、e tissue and suture anchor prior to knot tying.If the suture does not readily slide,a sliding or locking knot should not be used and a nonsliding knot should be chosenOnly one pair of sutures should be within the working cannula during arthroscopic knot tying.If more than one pair of sutures are wit
36、hin the working cannula during tying,there is a high likelihood that the sutures will become twisted and knot tying will become quite tedious if not impossible.Additional sutures should be shuttled via a monofilament suture(less tissue abrasion)or by an arthroscopic grasper to an accessory portalTra
37、nsparent cannulas are recommended for arthroscopic knot tying.These cannulas allow the surgeon to see if there is any twisting of the suture strands prior to knot tying37The arthroscopic surgeon should ensure that there is no redundant soft tissue around the tissue being apposed or in the path of th
38、e suture limbs because this will impede knot tying and increase the likelihood of knot failureWhen tying half hitches with a standard single-hole knot pusher,the first throw commonly slips when the knot pusher is removed in preparation for the second throw When the second throw is advanced,there is
39、a chance that the hitches will lock prior to complete apposition of the tissueTo prevent this,the surgeon can throw the first two hitches in the same direction allowing the hitches to slide down the post to appose the tissue Another method of preventing initial loop loosening is to use a double-diam
40、eter knot-pushing device,such as the Arthrex 6th to maintain tension on the initial hitch while throwing the second hitch38Non-Sliding KnotsFIGURE 16.A-F.Square knot.39Revo Knot The Revo knot is a series of multiple half hitches made by alternating the post and direction of the half hitches.There ha
41、ve been several modifications to the Revo knot FIGURE 17.A-H.Original Revo knot.40The Original Revo knot consists of two reversed half hitches on an identical post followed by post switching and two reversed half hitches.Throw an overhand loop around the post(Fig.17A).Pull the loop into the joint wi
42、th the knot pusher on the loop limb(Fig.17B)Withdraw the knot pusher while maintaining tension on the post limb.Throw an underhand loop around the same post(Fig.17C)Pull the loop into the joint and seat the knot with the knot pusher.Once the two hitches are seated,past-point to cinch the knot down(F
43、ig.17D).Switch posts and throw an underhand loop around the new post(Fig.17E).Pull the loop into the joint,seat the knot with the knot pusher,and past-point to cinch the knot down(Fig.17F).Next,throw an overhand loop around the post(Fig.17G).Pull the loop into the joint,seat the knot with the knot p
44、usher,and past-point to cinch the knot down.(Fig.17H)41Snyders Knot 4243Snyders Knot 44Snyders is another variation of the Revo knot Throw an overhand loop around the post(Fig.18A).Pull the loop into the joint with the knot pusher on the loop limb(Fig.18B)Withdraw the knot pusher while maintaining t
45、ension on the post limb.Throw an underhand loop around the same post(Fig.18C)Pull the loop into the joint and seat the knot with the knot pusher.Once the two hitches are seated,past-point to cinch the knot down(Fig.18D).Switch posts and throw an overhand loop around the new post(Fig.18E).Pull the lo
46、op into the joint,seat the knot with the knot pusher,and past-point to cinch the knot down(Fig.18F).Next,throw an underhand loop around the post(Fig.18G).Pull the loop into the joint,seat the knot with the knot pusher,and past-point to cinch the knot down(Fig.18H).Switch posts and throw an overhand
47、loop around the new post(Fig.18I).Pull the loop into the joint,seat the knot with the knot pusher,and past point to cinch the knot down(Fig.18J).45FIGURE 19.A-K.Revo knot.4647The current Revo knot is a modification of the Original Revo knotThrow an underhand loop around the post(Fig.19A).Advance the
48、 loop with the knot pusher on the loop limb until the first half hitch is seated(Fig.19B).Withdraw the knot pusher while maintaining tension on the post limb.Throw another underhand loop around the same post(Fig.19C).Pull the loop into the joint and seat the knot with the knot pusher.Once the two hi
49、tches are seated,past-point to cinch the knot down(Figs.19D,E).Throw an overhand half hitch around the post and advance with the knot pusher(Fig.19F).Further tension by past pointing and apply tension on both limbs while holding the (Fig.19G).Switch posts and throw an underhand loop around the new p
50、ost(Fig.19H).Pull the loop into the joint,seat the knot with the knot pusher,and past point to cinch the knot down(Fig.19I).Switch posts and throw an overhand loop around the new post(Fig.19J).Pull the loop into the joint,seat the knot with the knot pusher,and past point to cinch the knot down(Fig.1
