3:20-cv-00285
Arthrodesis Technology LLC v. Zimmer Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Arthrodesis Technology LLC (California)
- Defendant: Zimmer, Inc. and Zimmer US, Inc. (Delaware)
- Plaintiff’s Counsel: Meister Seelig & Fein LLP
- Case Identification: 3:20-cv-00285, D. Conn., 03/02/2020
- Venue Allegations: Plaintiff alleges venue is proper in the District of Connecticut because Defendant Zimmer, Inc. maintains a regular and established place of business in Stamford, CT, and conducts substantial business within the district.
- Core Dispute: Plaintiff alleges that Defendant’s Zimmer Phoenix Ankle Arthrodesis Nail System infringes a patent related to a surgical kit for performing ankle fusion surgery.
- Technical Context: The technology concerns orthopedic implants used for tibio-calcaneal arthrodesis, a surgical procedure to fuse the ankle joint, primarily for patients with severe arthritis, deformity, or bone degradation.
- Key Procedural History: The complaint alleges that Defendant has been aware of the patent-in-suit since at least October 17, 2011, when it was cited in an Information Disclosure Statement during the prosecution of one of Defendant's own patents. Plaintiff also alleges it sent a formal notice letter to Defendant on October 23, 2019.
Case Timeline
| Date | Event |
|---|---|
| 2000-08-02 | '293 Patent Priority Date |
| 2003-06-17 | '293 Patent Issue Date |
| 2011-10-17 | Alleged date of Zimmer's first knowledge of '293 Patent |
| 2019-10-23 | Date of Plaintiff's formal notice letter to Defendant |
| 2020-03-02 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,579,293 - “Intramedullary Rod with Interlocking Oblique Screw for Tibio-Calcaneal Arthrodesis,” issued June 17, 2003
The Invention Explained
- Problem Addressed: The patent describes prior art ankle fusion systems, which typically used a vertical rod and a roughly horizontal pin, as suffering from problems of “relative motion between the supposedly affixed tibial and calcaneal bones” (’293 Patent, col. 3:26-28). This motion could lead to instability, pain, and further damage to bones that were often already weakened by disease (’293 Patent, col. 3:28-34).
- The Patented Solution: The invention is a surgical kit comprising a vertical intramedullary rod and an “oblique screw” designed to be positioned at an acute angle relative to the rod (’293 Patent, col. 4:4-7). During surgery, the rod is inserted up through the heel bone (calcaneum) and into the shin bone (tibia). The oblique screw is then passed through the calcaneum and a slanted hole in the rod, where its threaded tip engages the lower tibial bone (’293 Patent, Abstract). Tightening the screw actively compresses the tibia against the calcaneum, creating a more stable and reliable fixation than was possible with prior art devices (’293 Patent, col. 4:10-13).
- Technical Importance: The use of an angled screw to generate active compression between the primary bones of the ankle joint represented a method to achieve a more robust and lasting surgical fusion (’293 Patent, col. 3:36-41).
Key Claims at a Glance
- The complaint asserts independent claims 1, 6, and 10, along with dependent claims 2-4, 7, and 8 (Compl. ¶12).
- Independent Claim 1 (a kit) requires:
- At least one “tibio-calcaneal rod” with an “oblique hole passing through the shaft.”
- At least one screw with a “threaded tip region.”
- The oblique hole passes through the rod's shaft “at an angle.”
- The screw's threaded tip region allows for establishing “compression of the tibial bone against the calcaneal bone when the screw is rotated.”
- The complaint reserves the right to assert other claims, as is standard.
III. The Accused Instrumentality
Product Identification
The Zimmer Phoenix Ankle Arthrodesis Nail System (the “Accused System”), which the complaint states includes “at least one screw and at least one nail” (Compl. ¶11).
Functionality and Market Context
The Accused System is identified as a medical device for orthopedic uses, specifically a surgical implant kit for performing ankle arthrodesis (Compl. ¶11). It is marketed and sold to “medical professionals, hospitals, and medical centers” (Compl. ¶13). The complaint alleges the system is specifically designed for this purpose and is “not suitable for substantial non-infringing use” (Compl. ¶14). Plaintiff further alleges that Defendant provides a “Surgical Technique Guide” and other instructions for using the system in a manner that infringes the ’293 Patent (Compl. ¶15).
IV. Analysis of Infringement Allegations
The complaint incorporates its detailed infringement allegations by reference to an exhibit (Exhibit B) which was not available for this analysis (Compl. ¶12). The following chart is based on the general allegations in the complaint.
No probative visual evidence provided in complaint.
'293 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a. at least one tibio-calcaneal rod having a tip, a shaft, and a base...and having an oblique hole... | The Accused System includes “at least one nail” that is alleged to be a tibio-calcaneal rod with the claimed features. | ¶11 | col. 11:35-41 |
| b. at least one screw having a base, a shaft, and a threaded tip region... | The Accused System includes “at least one screw” that is alleged to have the claimed features. | ¶11 | col. 11:42-49 |
| wherein the oblique hole passes through the shaft of the rod at an angle with respect to the shaft... | The complaint's theory of infringement requires that the screw of the Accused System passes through its nail at an angle. | ¶12 | col. 11:50-52 |
| and wherein the threaded tip region of the screw allows the screw to establish compression of the tibial bone against the calcaneal bone when the screw is rotated... | The Accused System is sold for ankle arthrodesis, and its alleged mode of operation involves using the screw to create compressive fixation, mirroring the function required by the claim. | ¶¶11, 14 | col. 11:55-59 |
Identified Points of Contention
- Scope Questions: A central question is whether the term “at an angle” in Claim 1 should be limited to the “acute angle” that the patent repeatedly identifies as its key inventive feature over prior art systems with “obtuse” angles (’293 Patent, col. 5:25-30). The infringement analysis will depend heavily on the geometry of the Accused System and the court’s construction of this term.
- Technical Questions: A key factual question will be whether Zimmer's “nail” constitutes a “tibio-calcaneal rod” as defined in the patent. Another is whether the interaction between the accused screw and nail generates “compression of the tibial bone against the calcaneal bone” in the specific manner claimed, or if it operates via a different mechanical principle.
V. Key Claim Terms for Construction
The Term: “at an angle with respect to the shaft”
- Context and Importance: The patent's entire inventive concept appears to rest on the distinction between the prior art's obtuse-angle pin and the invention's acute-angle screw. The construction of “at an angle” will therefore be critical; a broad construction may capture more products, while a narrow one limited to acute angles may be easier to defend from invalidity challenges but harder to prove infringement.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language of independent claim 1 does not contain the word “acute.” It merely requires “an angle,” which could be argued to encompass any non-parallel orientation.
- Evidence for a Narrower Interpretation: The specification strongly suggests the term should be limited. The abstract states the screw is “positioned at an acute angle” (’293 Patent, Abstract). The detailed description states the angle of the invention “will be an acute angle,” contrasting it with the prior art's obtuse angle (’293 Patent, col. 5:25-30). Practitioners may focus on this term because this evidence of a narrower scope could be used to argue for a non-infringement position if the accused device does not use an acute angle.
The Term: “tibio-calcaneal rod”
- Context and Importance: The Accused System is described as a “Nail System” (Compl. ¶11). The court will need to determine if Zimmer's “nail” falls within the scope of the claimed “rod.”
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent specification provides its own definition, stating, “As used herein, the terms 'rod', 'pin', and 'nail' are used interchangeably. All three terms refer to a rigid component that is inserted into one or more bones, for the purpose of anchoring, stabilizing, repairing, or supporting the bone(s)” (’293 Patent, col. 1:21-25). This explicit statement provides very strong intrinsic evidence that the patentee intended the term “rod” to be broad enough to encompass a “nail.”
- Evidence for a Narrower Interpretation: It would be difficult to argue for a narrower interpretation in the face of the patent's explicit lexicography. A defendant might be forced to argue that other structural or functional differences distinguish its “nail” from the claimed “rod,” but an argument based on the term itself appears weak.
VI. Other Allegations
Indirect Infringement
The complaint alleges inducement by asserting that Defendant provides customers with instructions, including a website and a “Surgical Technique Guide,” that guide users to perform the infringing method (Compl. ¶15, 22). Contributory infringement is alleged on the basis that the Accused System is a specialized kit not suitable for substantial non-infringing uses (Compl. ¶¶14, 23).
Willful Infringement
Willfulness is alleged based on pre-suit knowledge. Plaintiff claims Defendant has been aware of the ’293 Patent since at least October 17, 2011, when Defendant cited it as relevant prior art in an Information Disclosure Statement for its own patent application (Compl. ¶16). Plaintiff also cites its formal notice letter from October 2019 as establishing knowledge (Compl. ¶17). The complaint alleges Defendant continued its conduct despite this knowledge (Compl. ¶18, 25).
VII. Analyst’s Conclusion: Key Questions for the Case
A core issue will be one of claim construction: can the term “at an angle,” as used in Claim 1, be interpreted broadly, or will the court limit its scope to the “acute angle” that the patent specification consistently presents as the point of distinction over the prior art? The resolution of this question may be dispositive for infringement.
A key evidentiary question will be one of technical and functional correspondence: does the geometry of the Zimmer Phoenix Ankle Arthrodesis Nail System in fact align with the requirements of the asserted claims, as construed by the court? And functionally, does the tightening of the accused screw produce the specific “compression of the tibial bone against the calcaneal bone” as claimed?
The allegation of pre-suit knowledge since 2011 will be a central issue for willfulness. The court will examine the facts surrounding Defendant's citation of the '293 Patent in its own patent prosecution to determine if it establishes the level of knowledge and intent required for enhanced damages.