DCT

2:25-cv-00170

Syntorr Inc v. Arthrex Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00170, E.D. Tex., 04/23/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant is registered to do business in Texas, maintains a regular and established place of business in the District, transacts business in the District, and has consented to venue in prior litigation.
  • Core Dispute: Plaintiff alleges that Defendant’s orthopedic soft tissue repair devices, which incorporate suture anchors, infringe six patents related to variable denier suture technology.
  • Technical Context: The technology involves surgical sutures constructed with segments of different thicknesses (deniers), intended to allow a thinner end to pass easily through small surgical openings while providing a thicker, stronger portion for securing tissue.
  • Key Procedural History: The complaint alleges an extensive history of pre-suit communications, beginning in March 2014, in which Plaintiff's founder and inventor, Dr. Daniel Martin, allegedly disclosed his variable denier suture technology and developing patent portfolio to Defendant. Notably, Plaintiff alleges it provided Defendant with a copy of the issued U.S. Patent No. 8,881,635 and the patent application that led to U.S. Patent No. 11,116,498 in March 2015. This history forms the primary basis for the allegations of willful infringement.

Case Timeline

Date Event
2011-02-02 Earliest Priority Date ('635, '498 Patents)
2011-10-04 Earliest Priority Date ('241 Patent)
2014-03-01 Plaintiff alleges first communication with Defendant regarding technology
2014-11-10 Earliest Priority Date ('006 Patent)
2014-11-11 '635 Patent Issued
2015-03-27 Plaintiff alleges it provided issued '635 Patent to Defendant
2021-09-14 '498 Patent Issued
2022-03-31 Earliest Priority Date ('938, '766 Patents)
2022-07-14 Plaintiff alleges follow-up communication with Defendant identifying patent portfolio
2023-08-01 '241 Patent Issued
2023-11-07 '006 Patent Issued
2023-12-26 '938 Patent Issued
2025-02-12 Plaintiff alleges Defendant had knowledge of '241, '006, and '938 Patents
2025-04-22 '766 Patent Issued
2025-04-23 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 8,881,635 - "Variable Denier Yarn and Suture"

  • Issued: November 11, 2014

The Invention Explained

  • Problem Addressed: The patent's background section describes the difficulty in minimally invasive surgery of using sutures that are both thin enough to pass through the small opening of a surgical instrument and thick enough to provide strength and stability when securing tissue (U.S. Patent No. 8,881,635, col. 1:35-50). The problem is compounded when a suture must be looped and pulled through an opening, which effectively doubles its thickness (id., col. 1:44-48).
  • The Patented Solution: The invention is a suture constructed with sections of varying thickness, or "denier" (id., col. 2:40-42). It comprises a thinner "first segment" made of a certain number of strands, which is designed for easier passage, and a thicker "second segment" with more strands for greater strength (id., Abstract). The increased thickness is achieved by integrating a "second plurality of yarn elements" that are present in the thicker segment but not the thinner one, with the ends of these additional yarns terminating in the transition zone between the segments (id., col. 2:50-57).
  • Technical Importance: This variable-denier construction allows a single suture to combine the advantages of a thin suture (ease of threading) with those of a thick suture (strength and stability in tissue) (Compl. ¶ 68).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 6 (Compl. ¶ 98).
  • Essential elements of independent claim 1 include:
    • A suture comprising a first segment and a second segment aligned along a longitudinal axis.
    • The first segment has a plurality of first strands and a substantially constant first denier.
    • The second segment has a plurality of second strands and a substantially constant second denier.
    • The second segment has more strands than the first, resulting in a second denier greater than the first denier.
    • A first portion of the second strands is made from yarn that extends through both segments.
    • A second portion of the second strands is made from a "second plurality of yarn elements" present only in the second segment.
    • Ends of this second plurality of yarn elements are positioned substantially transverse to the longitudinal axis (Compl. ¶ 40).
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,116,498 - "Variable Denier Yarn and Suture"

  • Issued: September 14, 2021

The Invention Explained

  • Problem Addressed: Suturing techniques often require passing a doubled-over loop of suture through a suture lock. This necessitates a larger opening in the lock, which can result in a loose fit, "backlash," and potential loosening of the final repair when the single, thicker portion of the suture is ultimately secured ('498 Patent, col. 2:6-16).
  • The Patented Solution: The patent discloses a method of suturing that leverages a variable-denier suture to create a more secure, knotless repair. The method involves folding the thinner "first end segment" of the suture over a traction loop and pulling this doubled (but still thin) portion through the opening in a suture lock ('498 Patent, col. 4:51-54). The surgeon continues pulling until the thicker "second segment" is drawn into the opening. The key technical feature is that the total denier of the doubled first segment is less than the denier of the single second segment, which allows the second segment to create a much tighter, more secure fit in the opening ('498 Patent, col. 4:60-64).
  • Technical Importance: The claimed method provides for a more efficient and secure knotless suturing procedure by ensuring the final locked portion of the suture tightly fills the passage through which it was threaded ('498 Patent, col. 2:33-37).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶ 126).
  • Essential elements of independent claim 1 include:
    • A method of suturing, comprising: inserting a distal-most tip of a first end segment through a traction loop.
    • Folding the first end segment over on itself to form a doubled first end segment.
    • Pulling the traction loop and the doubled first end segment through an opening in a suture lock.
    • Continuing to pull until a second segment of the suture (with a greater denier than the first) extends through the opening.
    • Wherein a total denier of the doubled first end segment is less than the denier of the second segment, such that the fit of the second segment is tighter.
    • Locking the suture in place with the second segment in the opening (Compl. ¶ 47).
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,712,241 - "Variable Denier Yarn and Suture"

  • Issued: August 1, 2023 (Compl. ¶ 48)
  • Technology Synopsis: The patent is directed to a multi-denier suture for soft tissue repair constructed as a tubular braid. The suture has distal, middle, and proximal segments with progressively increasing deniers, achieved by adding a "second plurality of the strands" in the proximal segment whose ends terminate at a transition zone between the middle and proximal segments ('241 Patent, Abstract; Compl. ¶ 53).
  • Asserted Claims: Independent claims 1 and 37 are asserted (Compl. ¶ 147).
  • Accused Features: The variable denier sutures incorporated into the Accused Products are alleged to be multi-denier sutures with the claimed tubular braid structure and increasing denier segments (Compl. ¶¶ 149-158).

U.S. Patent No. 11,806,006 - "Variable Denier Yarn and Suture"

  • Issued: November 7, 2023 (Compl. ¶ 55)
  • Technology Synopsis: The patent is directed to a system for surgical repair and a surgical suture. The system comprises a variable-denier suture, a surgical implant with an opening, and a loop for pulling the thinner suture segment through the implant's opening ('006 Patent, Abstract; Compl. ¶ 60). The surgical suture claim requires the second segment to have a denier at least two times greater than the first segment (Compl. ¶ 61).
  • Asserted Claims: Independent claims 11 and 26 are asserted (Compl. ¶ 171).
  • Accused Features: The Accused Products are alleged to be systems for surgical repair that include the claimed variable-denier suture, a surgical implant, and a loop, and to include sutures meeting the claimed structure (Compl. ¶¶ 173, 183).

U.S. Patent No. 11,849,938 - "Variable Denier Yarn and Suture"

  • Issued: December 26, 2023 (Compl. ¶ 62)
  • Technology Synopsis: The patent is directed to a method of suturing similar to that of the '498 Patent. The method involves inserting a first end of a variable-denier suture through a loop, folding it over, and pulling the doubled-over (but still thin) first segment through an opening until the thicker second segment engages the opening ('938 Patent, Abstract; Compl. ¶ 67).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶ 194).
  • Accused Features: The ordinary use of the Accused Products is alleged to practice the claimed method of suturing (Compl. ¶¶ 199-208).

U.S. Patent No. 12,279,766 - "Variable Denier Yarn and Suture"

  • Issued: April 22, 2025 (Compl. ¶ 1)
  • Technology Synopsis: The patent is directed to a method of suturing similar to that of the '498 and '938 Patents. It claims a method of pulling a doubled-over thin segment of a variable-denier suture through a suture lock until the thicker segment engages, but specifically recites pulling the loop through a "sliding termination at a proximal end of the suture" and locking it with tension between the "restraint and the suture lock" ('766 Patent, Abstract; Compl. ¶¶ 219, 221, 223).
  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶ 213).
  • Accused Features: The ordinary use of the Accused Products is alleged to practice the claimed method of suturing (Compl. ¶¶ 218-223).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are the Arthrex 3 mm Knotless SutureTak®, Arthrex Knotless 1.8 FiberTak®, Knotless Corkscrew Meniscal Root repair device, and the Arthrex Knotless SwiveLock® anchor devices (collectively, the "Accused Products") (Compl. ¶ 75).

Functionality and Market Context

The Accused Products are identified as orthopedic soft tissue repair products and suture anchor devices that incorporate and rely on "variable denier suture technology" (Compl. ¶¶ 74-76). The complaint includes several photographs of the products, such as Figure 1, which shows an Arthrex SutureTak® product with a suture that has visibly different thicknesses along its length (Compl. Fig. 1, p. 18). Another image, Figure 2, shows the thinner portion of the suture already looped through the eyelet of the SutureTak® anchor, illustrating its intended method of use (Compl. Fig. 2, p. 18). The complaint alleges that Defendant is a "global medical devices manufacturer" and a "leader in new product development and medical education in orthopedics" (Compl. ¶¶ 72, 73).

IV. Analysis of Infringement Allegations

'635 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A suture, comprising: a first segment of suture comprising a plurality of first strands, the first segment having a substantially constant first denier; Each Accused Product has a first segment of suture comprising a plurality of first strands with a substantially constant first denier. ¶101 col. 2:42-44
and a second segment of suture comprising a plurality of second strands, the second segment having a substantially constant second denier; Each Accused Product has a second segment of suture comprising a plurality of second strands with a substantially constant second denier. ¶102 col. 2:44-47
wherein the first and second segments are aligned along a longitudinal axis of the suture; The first and second segments of the sutures in the Accused Products are aligned along a longitudinal axis. ¶103 col. 2:40-42
wherein there are more second strands in the second segment than first strands in the first segment such that the second denier is greater than the first denier; For each Accused Product, there are more second strands in the second segment than in the first segment, making the second denier greater than the first. ¶104 col. 2:47-50
wherein a first portion of the plurality of second strands is made from a first plurality of yarn elements that extend through the first segment and the second segment, In each Accused Product, a first portion of the second strands is made from a first plurality of yarn elements that extend through both the first and second segments. ¶105 col. 2:50-53
and wherein a second portion of the plurality of second strands is made from a second plurality of yarn elements that are present in the second segment and not the first segment, the first portion integrated around the second portion; In each Accused Product, a second portion of the second strands is made from a second plurality of yarn elements present only in the second segment, with the first portion integrated around this second portion. ¶106 col. 2:53-57
and wherein ends of the second plurality of yarn elements are positioned along an axis that is oriented substantially transverse to the longitudinal axis. The ends of the second plurality of yarn elements are positioned along an axis substantially transverse to the longitudinal axis. ¶107 col. 5:8-12
  • Identified Points of Contention:
    • Technical Questions: A primary technical question will concern the physical construction of the accused sutures. The complaint alleges, in conclusory fashion, that the sutures meet the specific limitation requiring a "second plurality of yarn elements that are present in the second segment and not the first segment." The case may depend on factual evidence from product teardowns demonstrating whether the increased denier is achieved by adding new, distinct yarn elements as claimed, or by some other technical means not covered by the claim.
    • Scope Questions: The interpretation of "integrated around" may be a point of dispute. The parties may contest whether the way the different yarn elements are combined in the accused sutures falls within the scope of this term as described in the patent.

'498 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of suturing, comprising: inserting a distal-most tip of a first end segment of a suture directly through a traction loop... Use of the Accused Products requires inserting a distal-most tip of a first end segment of a suture through a traction loop. ¶132 col. 4:51-52
folding the first end segment over on itself to form a doubled first end segment, the doubled first end segment including the distal-most tip; Use of the Accused Products requires folding the first end segment over on itself to form a doubled first end segment. ¶134 col. 4:51-52
pulling the traction loop and the doubled first end segment through an opening in a suture lock; Use of the Accused Products requires pulling the traction loop and the doubled first end segment through an opening in a suture lock. Figure 2 in the complaint depicts a suture looped in this manner. ¶135 col. 4:52-54
continuing to pull the first end segment through the opening such that a second segment of the suture extends through the opening, wherein the second segment has a...greater denier than the first end segment... Use of the Accused Products requires continuing to pull the suture until the thicker second segment extends through the opening. ¶136, ¶139 col. 4:55-58
wherein there is a gradual change in denier from the first end segment to the second segment as the second segment is pulled into the opening, There is a gradual change in denier from the first to the second segment as the second segment is pulled into the opening of the Accused Products. ¶140 col. 3:15-17
and further wherein a total denier of the doubled first end segment is less than the denier of the second segment such that a fit of the second segment in the opening is tighter than a fit of the doubled first end segment... A total denier of the doubled first end segment is less than the denier of the second segment, resulting in a tighter fit for the second segment in the opening. ¶141 col. 4:60-64
and locking the suture in place with the second segment in the opening. Use of the Accused Products requires locking the suture in place with the second segment in the opening. ¶142 col. 4:59-61
  • Identified Points of Contention:
    • Technical Questions: An evidentiary question will be whether the physical properties of the accused sutures meet the claim's relative denier requirement: "wherein a total denier of the doubled first end segment is less than the denier of the second segment." This will require precise measurement and expert analysis of the accused products.
    • Scope Questions: The analysis may raise the question of whether the "suture lock" in the Accused Products functions to achieve "locking the suture in place with the second segment in the opening" in the manner contemplated by the patent. Defendant may argue its products achieve fixation through a different mechanism that falls outside the scope of this functional language.

V. Key Claim Terms for Construction

  • The Term: "a second plurality of yarn elements that are present in the second segment and not the first segment" (from '635 Patent, Claim 1)

    • Context and Importance: This term is central to the infringement analysis for the '635 Patent as it defines the specific structure by which the suture's denier is increased. The dispute will likely focus on whether this requires the addition of entirely new, physically separate yarn elements in the thicker section, or if it can be read more broadly to cover other methods of increasing strand count.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: A party could argue that the claim's focus is on the result—more strands and higher denier—and that "yarn elements...not present in the first segment" should be interpreted functionally to cover any method that adds strand mass exclusively to the second segment.
      • Evidence for a Narrower Interpretation: The specification explicitly describes and illustrates the concept of certain "yarn elements...terminat[ing] in a transition zone" between segments, suggesting these are distinct physical components that do not run the full length of the suture ('635 Patent, col. 2:54-57). This language may support a narrower construction requiring physically distinct and truncated yarn elements.

  • The Term: "locking the suture in place with the second segment in the opening" (from '498 Patent, Claim 1)

    • Context and Importance: This functional language is critical for all asserted method claims. Its construction will determine whether infringement occurs only when the thicker "second segment" itself is the primary agent of locking within the "opening," or if it can cover scenarios where the second segment's presence merely enables a separate locking mechanism.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: A party may argue the term should be construed broadly to mean that the suture is locked when the second segment is positioned within the opening, regardless of the precise physical interaction, as this is the functional result of the claimed method.
      • Evidence for a Narrower Interpretation: The specification provides detailed discussion of how the larger diameter of the second segment "more nearly fills an entire dimension of the opening" to create a tight fit and resist movement, analogizing it to a Chinese finger trap ('498 Patent, col. 4:55-67, col. 22:5-10). This may support a narrower construction requiring the locking to result directly from the tight, friction-based fit of the second segment within the opening.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for the asserted method claims (Compl. ¶¶ 108-111, 127-129, 195-197, 214-216). Inducement is predicated on allegations that Defendant provides promotional materials, product manuals, and other instructions that direct and encourage surgeons to use the Accused Products in a manner that practices the patented methods (Compl. ¶¶ 108, 127). Contributory infringement is based on allegations that the Accused Products are a material part of the invention, are especially made or adapted for an infringing use, and are not staple articles of commerce suitable for substantial non-infringing use (Compl. ¶¶ 110, 129).
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents (Compl. ¶¶ 123, 144, 168, 191, 210, 225). The allegations are grounded in a detailed history of alleged pre-suit knowledge. Plaintiff alleges that Defendant knew of the patented technology since at least March 2014 and received a copy of the issued '635 Patent and the application leading to the '498 Patent on March 27, 2015 (Compl. ¶¶ 85, 122). For the more recently issued patents, knowledge is alleged as of at least July 2022, based on communications in which Plaintiff allegedly provided Defendant with a list of its growing intellectual property portfolio (Compl. ¶¶ 93, 143).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of technical proof: can Plaintiff provide sufficient evidentiary support, likely through reverse engineering and expert testimony, that the physical construction and material properties of Arthrex's various accused sutures meet the specific structural and relative-denier limitations recited in the asserted claims? The complaint's photographs, like Figure 4 showing the FiberTak® product, suggest a variable-denier design, but infringement will depend on the specific details of that design (Compl. Fig. 4, p. 19).
  • A second central question will be one of willfulness and intent: given the extensive pre-suit communications alleged in the complaint, which purportedly include the sharing of issued patents and pending applications years before the suit was filed, the focus will be on whether Arthrex's alleged infringement was objectively reckless.
  • Finally, the case may turn on a question of claim scope: can the functional term "locking the suture in place with the second segment," which appears in multiple asserted method patents, be construed to read on the specific locking mechanisms of the various Accused Products, or is there a fundamental mismatch in technical operation that places the accused methods outside the patent claims?