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Arthroscopic knot tying is a fundamental skill in minimally invasive orthopedic surgery. Although modern suture anchors, high-strength sutures, and knotless fixation devices have simplified many soft-tissue repair procedures, conventional arthroscopic knots remain important for rotator cuff repair, labral repair, shoulder stabilization, and other arthroscopic procedures.
The quality of an arthroscopic repair depends not only on the implant or suture material but also on how the suture is handled, how the knot is constructed, how tension is maintained, and whether the final knot remains stable under cyclic loading.
Arthroscopic knots can generally be divided into sliding knots, lockable sliding knots, and non-sliding knots. Each category has different mechanical and technical characteristics. Understanding these differences helps surgeons select an appropriate knot for the specific repair and tissue environment.
This article explains the terminology, principles, suture management techniques, and commonly used arthroscopic knot configurations, including the Duncan Loop, Tautline Hitch, Tennessee Slider/Buntline Hitch, SMC Knot, Alternating Half-Hitches, and Revo Knot.
Clinical note: Knot performance depends on suture material, knot configuration, tissue quality, anchor design, loading conditions, surgical technique, and the specific repair. The techniques described below are educational descriptions and should be performed only by appropriately trained orthopedic surgeons using validated surgical techniques and device instructions.
Precise terminology is important when discussing arthroscopic knot tying. The following concepts are commonly used to describe how sutures are manipulated.
The post suture strand is the suture strand that remains relatively straight and under tension while the other strand is wrapped around it to construct the knot.
The wrapping suture strand is the free strand that passes around the post to create the knot.
A sliding knot is constructed outside the joint and then advanced through a cannula toward the repair site. During knot advancement and tightening, the suture slides relative to the tissue and the knot.
A lockable sliding knot is a sliding knot that can be mechanically transformed into a more stable configuration after it reaches the repair site. Tension applied to the appropriate suture strand changes the knot configuration and increases resistance to slippage.
A non-sliding knot is constructed directly at or near the repair site. Individual half-hitches are advanced to the tissue without requiring the entire knot to slide along the suture through the tissue.
A locking half-hitch is an additional half-hitch used to secure a sliding knot and reduce the risk of the primary knot loosening or reversing under load.
In an overhand half-hitch, the wrapping strand passes over the post and then exits underneath it.
In an underhand half-hitch, the wrapping strand passes underneath the post and exits over it.
Reversed half-hitches are consecutive half-hitches constructed in alternating directions, such as an overhand half-hitch followed by an underhand half-hitch.
Alternating posts refers to changing which suture strand functions as the post during sequential half-hitches. Alternating the post can improve knot security by changing the direction and interaction of the suture strands.
Past pointing describes advancing the tip of the knot pusher beyond the knot during tightening. This can place the two suture strands in approximately opposite directions, allowing tension to be applied effectively to the knot.
During pushing, the knot pusher is placed on the post strand and the knot or half-hitch is advanced toward the repair site.
During pulling, the knot pusher is positioned on the wrapping strand while the half-hitch is drawn toward the repair site along the post.
The repair-site suture loop is the portion of suture passing through the repaired tissue. Tightening the loop brings the tissue edges together.
Successful arthroscopic knot tying begins before the first knot is constructed. Patient positioning, visualization, portal selection, cannula choice, and suture management all influence the quality of the final repair.
Patient positioning should provide adequate access to the relevant portion of the joint and allow the surgeon to manipulate instruments from appropriate directions.
For shoulder arthroscopy, both the beach-chair position and lateral decubitus position are commonly used. Depending on the procedure and surgeon preference, the operating table may be positioned to provide improved anterior, superior, or posterior access.
Good positioning should accomplish several objectives:
Provide stable access to the operative shoulder
Allow the arthroscope and instruments to approach the repair site at appropriate angles
Minimize interference between the surgeon, instruments, and anesthesia equipment
Facilitate suture passage and knot advancement
Maintain safe control of the patient's limb throughout the procedure
The exact position and traction parameters should be individualized according to the procedure, patient anatomy, and institutional protocol.
A clear visual field is essential for precise suture management.
Several measures may help maintain visualization:
Appropriate irrigation fluid flow
Controlled pump pressure
Effective management of bleeding
Careful use of electrosurgical hemostasis
Appropriate portal placement
Regular removal of debris from the joint
Low-pressure irrigation should be used when clinically appropriate, while hemodynamic management and controlled hypotension, when used, must follow appropriate anesthesia and patient-safety protocols.
Poor visualization increases the risk of suture entanglement, inaccurate tissue capture, and unintended cartilage or soft-tissue injury.
A portal that provides a direct working angle to the repair site can make suture passage and knot tying considerably easier.
Working from a distant portal can create several problems:
Instruments approach the repair at an unfavorable angle
The suture may contact the joint surface
Soft tissue may obstruct the working path
Knot advancement becomes more difficult
Excessive instrument manipulation may increase the risk of iatrogenic injury
An accessory portal can therefore provide a more direct trajectory for suture management and knot tying.
Portal placement should always be based on the anatomy, repair location, and the intended instrument trajectory.
Cannula selection is another important part of arthroscopic suture management.
Without an appropriate cannula, soft tissue can become interposed between suture strands during knot tying. This can interfere with knot seating and may potentially damage tissue caught between the sutures.
Transparent plastic cannulas are frequently useful because they allow visualization of the suture while providing a relatively soft interface compared with some metal cannulas.
Cannulas with features that improve soft-tissue retention can also help maintain a stable working channel during repeated instrument exchange.
The cannula should be selected according to the required instrument size, suture configuration, and surgical approach.
Arthroscopic soft-tissue repair may use different types of suture materials, including monofilament and braided sutures as well as absorbable and nonabsorbable materials.
Monofilament sutures generally pass smoothly through tissue and can be relatively easy to advance through many suture-passing devices.
Their low surface friction can be advantageous when the suture must slide through tissue or an anchor.
However, monofilament sutures may be more difficult to manipulate when constructing a compact knot because of their relative stiffness and memory.
Braided sutures are widely used in arthroscopic soft-tissue repair because of their handling characteristics.
Compared with many monofilament sutures, braided sutures generally:
Have a softer handling profile
Form compact knots more easily
Provide good knot-holding characteristics
Are available in a variety of high-strength configurations
However, braided sutures can be more susceptible to abrasion or damage during repeated instrument manipulation. Passing instruments through the suture or repeatedly grasping the same location can weaken the material.
Therefore, regardless of the selected suture, unnecessary manipulation should be minimized.
Selecting the correct post is an important part of arthroscopic knot tying.
When repairing soft tissue, it is often advantageous to use the suture strand passing through the more mobile tissue as the post. Applying tension to this strand can help bring the mobile tissue toward the relatively stable structure.
For example, during certain labral repairs, the suture strand passing through the capsular tissue may be selected as the post so that the final knot can be positioned appropriately away from the articular surface.
However, the optimal post depends on:
Tissue mobility
Tissue tension
Suture trajectory
Knot configuration
Desired final knot location
Repair anatomy
When tissue tension is minimal, knot position becomes particularly important. The final knot should be positioned where it does not interfere with joint motion or contact the articular surface unnecessarily.
Suture management is one of the most important technical steps in arthroscopic knot tying.
Crossed or twisted sutures can become trapped against the tissue surface. This may prevent complete tissue-to-tissue contact and interfere with healing.
Suture entanglement can also increase friction during knot advancement and make it difficult to fully tighten the repair.
Before advancing a suture loop, the surgeon should confirm that the strands are separated and oriented correctly.
A knot pusher can be passed along the post strand before introducing the next suture loop to help confirm that the strand is free within the cannula and working pathway.
Repeated manipulation with suture passers, graspers, and other instruments can damage the suture.
Potential problems include:
Surface abrasion
Partial fiber damage
Localized weakening
Unexpected suture breakage during knot tying
Therefore, unnecessary grasping and repeated passage through the same suture segment should be avoided.
When several sutures are present at the same repair site, identifying the correct suture pairs can become difficult.
Excessive numbers of loose suture strands may also obstruct visualization.
One practical strategy is to place and secure one suture pair before introducing the next whenever the surgical situation permits.
When multiple sutures must remain in the field, different suture colors can help identify individual pairs. Sutures associated with different repairs can also be brought out through separate working portals when appropriate.
Both open and arthroscopic repairs rely on knot security to maintain tissue approximation.
Knot security is influenced by several factors, including:
Number of throws
Knot configuration
Alternation of half-hitches
Suture material
Suture diameter
Friction between strands
Tissue tension
Cyclic loading
Suture handling
Quality of knot seating
In general, more complex knot configurations can provide greater resistance to slippage, but knot performance cannot be predicted solely by the number of throws.
Arthroscopic knots can be broadly divided into three groups:
Sliding knots
Lockable sliding knots
Non-sliding knots
A sliding knot is constructed away from the repair site and subsequently advanced into the joint.
Before choosing a sliding knot, the surgeon should confirm that the suture can move smoothly through:
The cannula
The soft tissue
The suture anchor, when present
The intended repair pathway
If excessive friction prevents smooth advancement, a non-sliding knot may be more appropriate.
The wrapping strand is passed around the post strand to construct the knot outside the joint.
The post is then tensioned while the knot pusher advances the knot toward the repair site.
As the knot travels toward the tissue, suture length changes because the strands slide relative to the tissue and cannula.
The wrapping strand should therefore have adequate length before the knot is constructed. If the wrapping strand is too short, it may retract into the cannula during knot advancement.
A simple sliding knot can potentially lose position under cyclic loading.
For this reason, a locking half-hitch or additional locking configuration is commonly added after the primary sliding knot is seated.
If the repair is under significant tension, the primary knot may begin to migrate before the locking half-hitch is secured.
Several technical strategies may help reduce this problem:
Temporarily reduce tissue tension when appropriate
Maintain tension on the post strand
Use a grasper to hold the reduced tissue
Use a knot pusher to stabilize the initial knot
Apply appropriate past-pointing technique
For example, during some rotator cuff repairs, changing the arm position may reduce repair-site tension and facilitate knot security. The exact position should depend on the repair and surgeon preference.
Lockable sliding knots are designed to reduce the risk of reverse slippage after the knot reaches the repair site.
Once the knot is seated, controlled tension on the wrapping strand changes the knot configuration and increases the interaction between the two suture strands.
However, the wrapping strand should not be prematurely tensioned while the knot is being advanced. Excessive early tension can cause the knot to lock before it reaches the intended repair site.
After the lockable sliding knot is fully seated, the surgeon can activate the locking mechanism and then add additional alternating half-hitches.
The final knot configuration should be checked for:
Complete tissue approximation
Appropriate knot position
Adequate tension
Absence of suture entanglement
Secure final fixation
Non-sliding knots are useful when the suture cannot move smoothly through the tissue or repair construct.
Instead of creating the complete knot outside the joint and advancing it, individual half-hitches are formed and seated directly at the repair site.
The major technical challenge is maintaining the repair tension while each successive half-hitch is constructed.
Maintaining post tension can help prevent the initial half-hitch from loosening.
A knot pusher can also be used to stabilize the first half-hitch while the subsequent throws are constructed.
Another important principle is alternating the post during the final throws. Repeatedly placing every half-hitch around the same post can produce a less stable configuration.
Several knot configurations are commonly discussed in arthroscopic surgery. No single knot is appropriate for every repair.
The following techniques illustrate different approaches to sliding, locking, and non-sliding knot construction.
The Duncan Loop is a commonly described arthroscopic sliding knot.
Place the knot pusher over the post strand and secure the post with a clamp or grasper as appropriate.
Advance the knot pusher into the joint and confirm that the suture is not twisted.
Position the strands so that the post is relatively short and the wrapping strand has sufficient length.
Form a loop with the wrapping strand and make multiple wraps around the post and wrapping strand according to the established Duncan Loop configuration.
Pass the free end through the loop.
Remove excess slack from the knot by sequentially tensioning the appropriate suture segments.
Maintain tension on the post while advancing the knot toward the repair site.
Seat the knot against the repaired tissue and eliminate residual slack from the repair loop.
Add a locking half-hitch.
Finish with additional alternating half-hitches to secure the construct.
The surgeon should confirm that the knot advances smoothly and that the repair does not lose reduction during knot locking.
The Tautline Hitch is another sliding configuration used in arthroscopic knot tying.
Place the knot pusher on the post strand and secure the post.
Advance the pusher into the joint and verify that the strands are free of twists.
Maintain a relatively short post and adequate length of wrapping strand.
Pass the wrapping strand over the post to create a loop.
Wrap the strand around the post through the loop according to the Tautline configuration.
Complete the additional wrap that creates the characteristic locking pathway.
Remove excess slack while avoiding premature locking.
Advance the knot toward the repair site while maintaining appropriate post tension.
Seat the knot completely against the repaired tissue.
Add additional reversed half-hitches with alternating posts.
The key technical point is controlling tension so that the knot remains capable of sliding during advancement but becomes stable once seated.
The Tennessee Slider, also described in relation to the Buntline Hitch, is a lockable sliding configuration.
Place the knot pusher on the post strand and secure the strand.
Pass the wrapping strand over the post and through the initial loop.
Construct the second wrap according to the Tennessee Slider configuration.
Remove excess slack without prematurely locking the knot.
Advance the knot toward the repair site while maintaining post tension.
Seat the knot completely at the repair site.
Apply controlled tension to the wrapping strand to deform the knot and activate the locking mechanism.
Add additional alternating reversed half-hitches to reinforce the final knot.
The surgeon should avoid excessive tension on the locking strand before the knot reaches the repair site.
The SMC knot is another lockable sliding configuration used in arthroscopic soft-tissue repair.
Place the knot pusher over the post strand and secure the strand.
Form the initial wraps around the post and the suture strands according to the SMC configuration.
Continue the wrapping sequence to create the characteristic locking loop.
Pass the wrapping strand through the appropriate portion of the developing knot.
Maintain control of the locking loop while removing excess slack.
Advance the knot along the post toward the repair site.
Do not prematurely tighten the locking loop, because doing so can prevent the knot from advancing.
Once the knot is completely seated, maintain post tension.
Apply pressure with the knot pusher while tensioning the wrapping strand to activate the locking mechanism.
Finish with alternating half-hitches.
The SMC configuration illustrates an important principle of lockable sliding knots: the knot must remain mobile during advancement and become mechanically secure only after it reaches the intended repair site.
Alternating half-hitches are frequently used to secure a sliding or lockable sliding knot.
Construct an overhand half-hitch around the post.
Advance the half-hitch to the repair site and seat it firmly.
Maintain tension and remove the knot pusher.
Transfer the knot pusher to the opposite suture strand, making that strand the new post.
Construct an underhand half-hitch around the new post.
Advance and tighten the second half-hitch.
Return the knot pusher to the original strand.
Construct the next half-hitch in the opposite direction.
Continue the alternating sequence as required by the repair and knot configuration.
The alternating-post principle helps create a more mechanically stable knot construct than repeatedly placing all half-hitches around the same strand.
The Revo knot is a non-sliding knot configuration constructed directly at the repair site.
Construct an overhand half-hitch around the post.
Advance the first half-hitch to the tissue and maintain post tension.
Construct a second overhand half-hitch around the same post.
Advance and tighten the second throw to secure the first.
Construct a reversed underhand half-hitch while maintaining post tension.
Transfer the knot pusher to the opposite suture strand so that the opposite strand becomes the new post.
Construct an additional overhand half-hitch around the new post.
Use the past-pointing technique to tighten the throw while maintaining control of the existing knot.
Return the knot pusher to the original post.
Construct the final reversed half-hitch and tighten it securely.
The Revo configuration demonstrates why alternating the post during the final throws is important for maintaining knot security.
Knot tying is a technical skill that improves with structured practice.
Surgeons learning arthroscopic knot techniques can focus on several fundamental principles.
Before performing complex arthroscopic knots clinically, surgeons can practice knot configurations using simulation models or bench-top training systems.
The goal should be to develop consistent:
Strand identification
Hand positioning
Tension control
Knot formation
Knot advancement
Knot seating
Final locking
Rather than attempting to memorize a large number of configurations immediately, surgeons can first become proficient with:
One reliable sliding knot
One lockable sliding knot
One non-sliding knot
Alternating half-hitches
This creates a practical foundation for selecting an appropriate configuration during different repairs.
Many knot-related problems originate from poor tension control rather than from the knot configuration itself.
Before tightening the final throws, confirm:
The tissue is appropriately reduced
The repair loop has no unnecessary slack
The post is controlled
The knot is completely seated
The suture is not twisted
High-strength sutures can still be damaged by aggressive or repeated instrument manipulation.
Avoid repeatedly grasping the same section of suture and minimize unnecessary passage through sharp instruments.
Potential causes include:
Inadequate knot configuration
Insufficient locking throws
Excessive tissue tension
Poor post selection
Incomplete knot seating
Suture material with unfavorable handling characteristics
A lockable sliding knot may lock before reaching the repair site if the locking strand is tensioned too early.
The solution is to maintain controlled tension and delay activation of the locking mechanism until the knot is correctly positioned.
Crossed or twisted strands can interfere with knot advancement and tightening.
The solution is careful suture identification and management before constructing the knot.
Repeated instrument manipulation, abrasion, or excessive tension can damage the suture.
Minimizing unnecessary manipulation and using appropriate instruments can reduce this risk.
A technically secure knot may still be undesirable if it is positioned against the articular surface or interferes with joint motion.
The final position should therefore be considered during the entire knot-tying process rather than only after the knot has been completed.
| Knot category | Main characteristic | Typical advantage | Important consideration |
|---|---|---|---|
| Sliding knot | Constructed outside the joint and advanced | Efficient advancement and tissue approximation | May require additional locking throws |
| Lockable sliding knot | Slides initially and locks after seating | Combines advancement with increased resistance to slippage | Premature locking must be avoided |
| Non-sliding knot | Constructed directly at the repair site | Useful when suture sliding is limited | Requires careful tension control during each throw |
The appropriate knot should be selected according to the repair anatomy, suture behavior, tissue quality, access, and surgeon experience.
Arthroscopic knot techniques may be incorporated into a variety of soft-tissue repair procedures, including:
Knot tying can be used to secure tendon tissue to the greater tuberosity in selected repair constructs.
Arthroscopic knots may be used during anterior, posterior, or superior labral repair to secure the labrum and capsular tissue.
Bankart and other capsulolabral procedures may require controlled suture tension and secure knot fixation.
Similar principles may be applied in other joints and procedures where suture-based soft-tissue fixation is used.
The exact knot configuration should be selected according to the procedure and fixation construct rather than applied universally.
Arthroscopic knots are commonly categorized as sliding knots, lockable sliding knots, and non-sliding knots.
Both knots can be advanced toward the repair site. A lockable sliding knot incorporates a mechanism that changes the knot configuration after seating, increasing resistance to reverse slippage.
The post determines how tension is transferred during knot advancement and tightening. Selecting an appropriate post can facilitate tissue reduction and help position the final knot appropriately.
Alternating the post changes the direction of successive throws and can improve the mechanical stability of the final knot construct.
A non-sliding knot may be useful when the suture cannot move smoothly through the tissue, cannula, or fixation construct, making a sliding knot difficult to advance safely.
No. Knot selection depends on the repair anatomy, tissue tension, suture material, access, fixation construct, and surgeon experience.
In lockable sliding knots, excessive tension on the locking strand before the knot reaches the repair site can activate the locking mechanism too early and prevent further advancement.
Arthroscopic knot tying is more than simply creating a secure knot. Successful knot management requires coordinated control of patient positioning, visualization, portal selection, cannula choice, suture handling, post selection, tissue tension, knot advancement, and final fixation.
Duncan Loop and Tautline Hitch represent commonly described sliding configurations, while the Tennessee Slider and SMC Knot provide examples of lockable sliding knots. Alternating Half-Hitches can be used to reinforce sliding knots, while the Revo Knot demonstrates a non-sliding approach.
The most important principle is not to memorize the largest possible number of knots, but to understand how each knot behaves during advancement, seating, locking, and cyclic loading. Proper suture management and consistent technique are equally important to the final stability of the repair.
For orthopedic surgical instrument manufacturers and medical-device companies, reliable arthroscopic knot-tying workflows also highlight the importance of compatible suture management instruments, knot pushers, graspers, suture passers, cannulas, and arthroscopic accessories.
