Arthroscopic Knot Tying: An Instruction Manual

99 Pages·2004·4.624 MB·English

by  Keith M. Baumgarten, Rick W. Wright

Arthroscopic Knot Tying
An Instruction Manual

1st Edition
2005
Lippincott Williams & Wilkins
Philadelphia
530 Walnut Street, Philadelphia, PA 19106 USA
978-0-7817-5903-8
0-7817-5903-X
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© 2005 LIPPINCOTT WILLIAMS & WILKINS
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Library of Congress Cataloging-in-Publication Data
Baumgarten, Keith M.
Arthroscopic knot tying : an instruction manual/Keith M. Baumgarten, Rick W. Wright.
p. ; cm
Includes bibliographical references.
ISBN 0-7817-5903-X (pbk.)
1. Joints—Endoscopic surgery—Handbooks, manuals, etc. 2. Arthroscopy—Handbooks, manuals, etc.3. Suturing—
Handbooks, manuals, etc.
I. Wright, Rick W. II. Title.
[DNLM: 1. Suture Techniques. 2. Arthroscopy—methods. WO 166 B348a 2004]
RD686.B33 2004
617.4′720597—dc22
2004015935
Care has been taken to confirm the accuracy of the information presented and to describe generally accepted
practices. However, the authors, editors, and publisher are not responsible for errors or omissions or for any
consequences from application of the information in this book and make no warranty, expressed or implied, with
respect to the currency, completeness, or accuracy of the contents of the publication. Application of this
information in a particular situation remains the professional responsibility of the practitioner.
The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in
this text are in accordance with current recommendations and practice at the time of publication. However, in
view of ongoing research, changes in government regulations, and the constant flow of information relating to drug
therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in
indications and dosage and for added warnings and precautions. This is particularly important when the
recommended agent is a new or infrequently employed drug.
Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance
for limited use in restricted research settings. It is the responsibility of the health care provider to ascertain the
FDA status of each drug or device planned for use in their clinical practice.
10 9 8 7 6 5 4 3 2 1
Authors
Keith M. Baumgarten M.D.
Chief Resident
Department of Orthopaedic Surgery
Washington University School of Medicine
St. Louis, Missouri
Rick W. Wright M.D.
Assistant Professor
Department of Orthopaedic Surgery
Washington University School of Medicine
St. Louis, Missouri
Preface
The number of arthroscopic operations performed is increasing each year. Indications for arthroscopic
surgery are also expanding. Arthroscopic surgery is favorable to open surgery because large arthrotomies
are avoided, thereby decreasing post-operative pain and allowing for faster rehabilitation. In addition,
arthroscopic surgery has a lower rate of infectious complications than does open surgery.
The ability to tie arthroscopic knots is essential to arthroscopic surgery. Arthroscopic knot tying is
technically demanding and more difficult than manual knot tying. It is imperative that the arthroscopic
surgeon be able to tie secure knots that maintain tissue apposition until biologic healing occurs.
With the heightened popularity of arthroscopic surgery, the number of commonly used arthroscopic knots
and the number of surgeons using these knots has increased. Most arthroscopic surgeons have not been
systematically trained to tie many of the knots that are described in the arthroscopic literature. Rather,
most surgeons use only one or two knots that they learned from their mentors.
This manual is a comprehensive resource for learning arthroscopic knot tying. It is a compilation of all
arthroscopic knots described in the literature. In addition, it reviews several laparoscopic knots that may
be considered for use in arthroscopy. With this manual, we hope to assist the novice arthroscopic surgeon
in learning to tie arthroscopic knots, and we wish to allow the experienced surgeon to expand their
repertoire of arthroscopic knots.
Contents
Preface
Contents
Introduction
Knot Tying Principles
Knot Terminology
Arthroscopic Knot Pushers
Suture Properties
Knot Types
Knot Pushing and Pulling
Tying Half Hitches
Optimal Configuration of Half Hitches
Post Switching
Arthroscopic Knot-Tying Techniques
Non-Sliding Knots
Sliding Knots
Ratchet Knots
Locking Knots
Laparoscopic Knots
Biomechanical Studies
Index
P.1

Introduction
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 procedures is the ability to tie arthroscopic knots to approximate
intraarticular tissues and thereby avoid the need for large arthrotomies. Arthroscopic knot tying is more
difficult than manual knot tying because 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 practice. With the heightened popularity of arthroscopic surgery,
the number of commonly used arthroscopic knots and the number of surgeons using these knots has
increased. It is our intention to provide instruction on how to tie all of the arthroscopic knots that have
been described in the literature.

Knot Tying Principles
The goal of knot tying is to approximate tissue under tension and maintain the tissue in apposition until
biologic repair and healing can occur. It is imperative for all surgeons to learn and use knot-tying
techniques that minimize the chance of knot failure. Knot failure can occur through four different
processes: 1) knot slippage and loosening, 2) suture breakage, 3) tissue failure, and 4) suture anchor
pullout from bone.
Knot security is a term that describes the ability of a knot to resist slippage once tying is completed and a
load is applied (4 ,6 ,7 ). There are three factors that determine knot security: friction, internal
interference, and slack between throws. Friction is inherent to the suture material. For example, braided
suture has a higher coefficient of friction than does monofilament. Internal interference is determined by
the configuration of the knot and increased by the length of the contact between the loop limb and the
post limb. Reversing the direction of half hitches and alternating posts increases the internal interference
of a knot. Lastly, the surgeon should minimize the slack between the individual throws in each knot to
maximize loop security (5 ). This can be done by removing twists in the suture between throws to ensure
the knots lie flat and by past pointing to cinch the suture down tightly to reduce internal knot looseness.
If an individual loop slips during the process of knot tying, the tissue will lose its apposition, which is
necessary to ensure biologic healing and repair. It has been suggested that more than two to three
millimeters of knot slippage can lead to failure of tissue apposition (3 ,24 , 25 , 26 ,38 ,39 ). Knots that
fail through slippage have been shown to have less strength (i.e., knot-holding capacity) than knots that
fail through suture rupture (10 ).
In addition to slippage, knot failure can occur through suture breakage. Suture rupture is usually due to
shear forces rather than tensile forces because the tensile strength of a suture is larger than its shear
strength. The most common shear point is at the knot where the suture bends into the body of the knot
and the tensile forces are converted to shear forces (10 ). Suture breakage can occur at other sites as
well if there is a weakness in the suture. This may occur if the suture is weakened by instrument
manipulation or if the suture becomes frayed by repeated sliding of one suture limb over the other,
especially with materials that have a high coefficient of friction (e.g., uncoated, braided polyester).
The third mechanism of knot failure is tissue failure. The suture can pull through the tissue being apposed.
This may happen in atrophic tissue or in normal tissue that is damaged by the suture. Suture-derived
tissue damage occurs when the suture “saws” through the tissue leading to tissue failure and suture
pullout. This situation may be minimized by using a suture with a lower coefficient of friction such as a
monofilament suture.
P.2

The last mechanism of knot failure is bone failure. This occurs in tissue apposition constructs that are
implanted in bone such as a suture anchor. Suture anchor pullout can occur if the bone is osteopenic and
unable to resist the forces across the apposed tissue. Suture anchor pullout may also occur if two or more
suture anchors are placed too close together and the remaining local bone is inadequate to resist the
tensile forces across the tissue. It has been recommended that the anchors be placed at least one
centimeter apart to minimize the risk of anchor pullout (4 ). The knot itself represents the weakest point
in the suture-knot configuration (13 ). In an experiment of 720 hand-tied knots, the knot failed by
loosening or breakage in the knot or immediately adjacent to the knot in 710 of the knots (37 ).

Knot Terminology
An arthroscopic knot is constructed by tying one suture limb around another suture limb. One limb is
known as the post limb (also commonly known as the axial limb) and the other limb is known as the 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 limb (Fig. 1 ). The post is generally chosen as the limb
farthest from the center of the joint.

FIGURE 1. Loop and post configuration.

Arthroscopic 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. There are many different types of arthroscopic knot pushers (Figs. 2 , 3 ). Included
among these are single-hole knot pushers, double-hole knot pushers (Fig. 4 ) 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 pushers (5 ).
P.3

FIGURE 2. Arthrex knot pushers. A. Single-hole, B. Double-hole, C. 6th Finger.

FIGURE 3. Mitek knot pushers. A. Single-hole, B. Double-hole, C. Slotted.

FIGURE 4. Double-hole knot pusher.
P.4