DCT
1:19-cv-02093
Zimmer US Inc v. ConforMIS Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Zimmer US, Inc. (Delaware) and Biomet Manufacturing, LLC (Indiana)
- Defendant: Conformis, Inc. (Delaware)
- Plaintiff’s Counsel: Paul Hastings LLP
- Case Identification: 1:19-cv-02093, D. Del., 11/05/2019
- Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant is a Delaware corporation.
- Core Dispute: Plaintiff alleges that Defendant’s patient-specific knee replacement systems infringe five patents related to methods for producing patient-specific orthopedic implants and associated surgical guide tools.
- Technical Context: The technology involves using patient-specific medical imaging, such as CT scans, to design and manufacture customized knee implants and surgical guides intended to improve surgical accuracy and patient outcomes.
- Key Procedural History: The complaint does not mention any prior litigation, inter partes review (IPR) proceedings, or licensing history between the parties concerning the patents-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2000-11-14 | U.S. Patent No. 6,510,334 Priority Date |
| 2003-01-21 | U.S. Patent No. 6,510,334 Issue Date |
| 2007-04-17 | U.S. Patent No. 8,486,150 Priority Date |
| 2007-04-17 | U.S. Patent No. 8,979,936 Priority Date |
| 2007-07-03 | U.S. Patent No. 9,795,399 Priority Date |
| 2007-08-02 | U.S. Patent No. 9,173,661 Priority Date |
| 2013-07-16 | U.S. Patent No. 8,486,150 Issue Date |
| 2015-03-17 | U.S. Patent No. 8,979,936 Issue Date |
| 2015-11-03 | U.S. Patent No. 9,173,661 Issue Date |
| 2017-10-24 | U.S. Patent No. 9,795,399 Issue Date |
| 2019-11-05 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,510,334 - Method of Producing an Endoprosthesis as a Joint Substitute for a Knee Joint
- Patent Identification: U.S. Patent No. 6,510,334, titled "Method of Producing an Endoprosthesis as a Joint Substitute for a Knee Joint," issued on January 21, 2003.
The Invention Explained
- Problem Addressed: The patent's background describes how conventional knee replacement surgeries use industrially manufactured, standard-sized implants. Fitting these off-the-shelf components can be time-consuming and may result in an imperfect fit, leading to complications such as incorrect patella gliding and subsequent joint irritation (’334 Patent, col. 1:15-55).
- The Patented Solution: The invention is a method that uses a preoperative tomographic image (e.g., a CT scan) of a patient's damaged knee. This image is first "virtually altered" to approximate the contours of a healthy knee. Then, the method involves "virtually severing" the altered image to create visual patterns for both the implant components and a corresponding "implantation aid" or surgical guide. This patient-specific guide is designed with slots or other features that correspond to the virtual severing areas, intended to guide the surgeon's tools during the actual operation (’334 Patent, Abstract; col. 3:15-51).
- Technical Importance: This approach represents an early method for leveraging patient-specific digital imaging to pre-plan orthopedic surgery and create custom surgical tools, aiming to minimize error rates and improve the fit of the final prosthesis (’334 Patent, col. 2:39-47).
Key Claims at a Glance
- The complaint asserts at least independent Claim 1 (Compl. ¶28). The essential elements are:
- preparing a preoperative tomographic image of the damaged knee joint;
- virtually altering the preoperative tomographic image for approximating the contours... to those of a healthy knee joint;
- virtually severing the altered femoral and tibial components... as respectively visual patterns for the endoprosthesis;
- virtually transferring the marked severing areas for virtually preparing tomographic images of a femoral and of a tibial template... as respectively separate visual patterns of an implantation aid; and
- preparing three-dimensional femoral and tibial components of the endoprosthesis and... implantation aid on the basis of their respective visual patterns.
U.S. Patent No. 8,486,150 - Patient-modified Implant
- Patent Identification: U.S. Patent No. 8,486,150, titled "Patient-modified Implant," issued on July 16, 2013.
The Invention Explained
- Problem Addressed: The patent acknowledges that while fully custom implants can provide an excellent fit, they often require custom surgical guides and instruments, which can increase inventory and complexity for hospitals and surgeons (’150 Patent, col. 1:23-31).
- The Patented Solution: The patent describes a "semi-custom" or "patient-modified" implant. The method starts with a digital image of a standard implant that has a "non-custom inner bone-engaging surface," which is designed to mate with standard, non-patient-specific bone cuts. Key external features, such as the anterior femoral flange, are then modified in the digital model to match the specific patient's anatomy derived from a 3D image. The final implant is manufactured from this modified digital model, creating a hybrid that is patient-specific on its articulating surface but standard on its bone-engaging surface (’150 Patent, Abstract; col. 2:46-62).
- Technical Importance: This hybrid approach aims to provide the patient-matching benefits of a custom implant while retaining compatibility with standard surgical tools and bone-preparation techniques, potentially reducing cost and complexity (’150 Patent, col. 1:27-31).
Key Claims at a Glance
- The complaint asserts at least independent Claim 1 (Compl. ¶39). The essential elements are:
- constructing a three-dimensional digital image of a patient's joint using computer modeling;
- obtaining a digital image of a femoral implant having a non-custom inner bone-engaging surface including a plurality of planar surfaces configured for engagement with standard size femoral bone cuts;
- modifying the digital image of the femoral implant by configuring an anterior femoral flange... to have a patient-specific shape and size... based on the three-dimensional image of the patient's joint; and
- manufacturing the femoral implant based on the digital image.
U.S. Patent No. 8,979,936 - Patient-modified Implant
- Patent Identification: U.S. Patent No. 8,979,936, titled "Patient-modified Implant," issued March 17, 2015.
- Technology Synopsis: This patent extends the "semi-custom" implant concept to the tibial components of a knee replacement. It claims an orthopedic implant where the tibial tray has a patient-specific outer profile, configured preoperatively from a 3D digital image to match the patient's tibia, while retaining a "non-custom locking mechanism" for coupling with a standard tibial bearing insert. This is achieved by modifying a digital image of a non-custom tibial implant without altering the locking feature (’936 Patent, col. 2:7-16).
- Asserted Claims: At least Claim 1 (Compl. ¶47).
- Accused Features: The prosthetic knee implants of the Accused Products, which allegedly utilize a patient-specific tibial tray configured preoperatively via the iFit software (Compl. ¶50).
U.S. Patent No. 9,173,661 - Patient Specific Alignment Guide with Cutting Surface and Laser Indicator
- Patent Identification: U.S. Patent No. 9,173,661, titled "Patient Specific Alignment Guide with Cutting Surface and Laser Indicator," issued November 3, 2015.
- Technology Synopsis: The patent describes a method of guiding a surgical instrument using a patient-specific guide made of two separable portions. Each portion has an inner surface that conforms to a different unresected surface of the patient's bone (e.g., anterior and distal femur). After the assembled guide is secured to the bone with a pin through the first portion, the second portion is removed, and a cutting instrument is then guided through an opening in the first, remaining portion (’661 Patent, Abstract).
- Asserted Claims: At least Claim 8 (Compl. ¶55).
- Accused Features: The G2CR and PS surgical technique guides ("iJigs") and the instructions provided for their use (Compl. ¶54).
U.S. Patent No. 9,795,399 - Patient-specific Knee Alignment Guide and Associated Method
- Patent Identification: U.S. Patent No. 9,795,399, titled "Patient-specific Knee Alignment Guide and Associated Method," issued October 24, 2017.
- Technology Synopsis: This patent claims a method of preparing a knee joint by mating a patient-specific guide, having a 3D curved inner surface, onto the corresponding bone surface. The guide's shape is preoperatively configured from medical scans. The method involves drilling holes into the bone through apertures in the guide and then placing members (e.g., pins) into those holes to secure the guide for subsequent surgical steps (’399 Patent, Abstract).
- Asserted Claims: At least Claim 1 (Compl. ¶69).
- Accused Features: The G2CR and PS surgical technique guides ("iJigs") and the instructions provided for their use (Compl. ¶68).
III. The Accused Instrumentality
Product Identification
- The iUni G2 Patient-Specific Unicompartmental Knee Resurfacing System, the iDuo G2 Patient-Specific Bicompartmental Knee Resurfacing System, the iTotal G2 Patient-Specific Cruciate-Retaining Knee Replacement System, and the iTotal PS Customized Posterior-Stabilized Knee Replacement System (collectively, "the Accused Products") (Compl. ¶17).
Functionality and Market Context
- The Accused Products are patient-specific knee joint replacement systems. The complaint alleges they utilize Conformis’s proprietary “iFit® image-to-implant technology,” which uses software to convert a CT scan of a patient’s knee into a three-dimensional model (Compl. ¶19). This model is then allegedly used to design patient-specific implants and surgical instrumentation, referred to as "iJigs" (Compl. ¶19). The system also provides surgeons with "iView" planning images containing patient-specific resection values and positioning information for the iJigs (Compl. ¶20). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
U.S. Patent No. 6,510,334 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| preparing a preoperative tomographic image of the damaged knee joint; | The iFit software utilizes CT imaging to create a three-dimensional model of the patient's joint. | ¶29 | col. 2:56-65 |
| virtually altering the preoperative tomographic image for approximating the contours of at least the femoral bone and of the tibia... to those of a healthy knee joint; | The iFit software uses a patient's CT scan to map the knee joint surface and correct the data for arthritic deformities such as bone spurs. | ¶30 | col. 2:66-3:14 |
| virtually severing the altered femoral and tibial components defining respective components of a healthy knee joint as respectively visual patterns for the endoprosthesis...; | The iFit software generates patient-specific tibial and femoral resection values and positioning information, shown in iView planning images. | ¶31 | col. 3:15-24 |
| virtually transferring the marked severing areas for virtually preparing tomographic images of a femoral and of a tibial template for the femoral and the tibial components of the damaged knee joint...; | The Accused Products' iJigs are patient-specific, designed based on the knee mapping, and are designed to sit flush against the bone. Severing areas are exemplified as virtual guiding slots. | ¶33, ¶34 | col. 3:41-4:4 |
| preparing three-dimensional femoral and tibial components of the endoprosthesis and... implantation aid on the basis of their respective visual patterns. | Conformis's manufacturing process uses iFit software to design patient-specific implants and instrumentation by converting a CT scan into a 3D model. | ¶35 | col. 4:5-14 |
Identified Points of Contention
- Scope Questions: A central question may be whether Conformis's software process constitutes "virtually severing" an "altered" image to create "visual patterns" for both the implant and a separate "implantation aid." The defense may argue that its integrated design process does not map cleanly onto this sequence of discrete virtual steps.
- Technical Questions: What evidence does the complaint provide that the "resection values" generated by the iFit software are derived from "virtually severing" a modeled "healthy knee joint," as opposed to being calculated directly from the patient's damaged anatomy with predetermined offsets?
U.S. Patent No. 8,486,150 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| constructing a three-dimensional digital image of a patient's joint using computer modeling; | The iDuo, G2CR, and PS products are manufactured using iFit software, which uses CT images to create a three-dimensional model of the patient's joint. | ¶40 | col. 13:38-41 |
| obtaining a digital image of a femoral implant having a non-custom inner bone-engaging surface... configured for engagement with standard size femoral bone cuts...; | The accused implants allegedly utilize a non-articulating inner bone-engaging surface with a "standard multiple chamfer cut design that is not patient-specific." | ¶41 | col. 13:50-54 |
| modifying the digital image of the femoral implant by configuring an anterior femoral flange... to have a patient-specific shape and size...; | The accused implants allegedly include a patient-specific anterior femoral flange made based on the iFit software's 3D modeling of the patient's joint. | ¶42 | col. 13:59-14:1 |
| manufacturing the femoral implant based on the digital image. | The iDuo, G2CR, and PS products are allegedly manufactured using iFit software that designs the implant to match the 3D model of the patient's knee. | ¶43 | col. 14:2-3 |
Identified Points of Contention
- Scope Questions: The dispute may turn on the definition of a "non-custom inner bone-engaging surface." Does the use of a "standard multiple chamfer cut design" meet this limitation if other minor aspects of the inner surface are adjusted for the patient?
- Technical Questions: Does the complaint offer evidence that Conformis's process begins with a pre-existing "digital image of a femoral implant" that is then "modified," or does Conformis generate its implant designs from the ground up based on patient anatomy, potentially avoiding this claim element?
V. Key Claim Terms for Construction
For U.S. Patent No. 6,510,334:
- The Term: "virtually altering"
- Context and Importance: This term defines a foundational step of the claimed method. Its construction is critical because the infringement analysis will depend on whether Conformis’s software performs an action that falls within the scope of "altering" a tomographic image to approximate a "healthy knee joint." Practitioners may focus on this term because it distinguishes the invention from methods that might design an implant based solely on the damaged anatomy.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification suggests this step "may be exemplified manually or may alternatively be exemplified by the preparation of a mirror image of a healthy knee joint of the patient" (’334 Patent, col. 3:7-11), implying that multiple techniques could satisfy the "altering" step.
- Evidence for a Narrower Interpretation: The patent describes the goal of the alteration is to obtain "more or less ideal contours for the fitting of the endoprosthesis" and to approximate "the contours of a healthy knee joint" (’334 Patent, col. 3:1-3, 6-7). This could be argued to require a complete or substantial recreation of a healthy joint's geometry, not just minor corrections for deformities.
For U.S. Patent No. 8,486,150:
- The Term: "non-custom inner bone-engaging surface"
- Context and Importance: This term is central to the patent's "semi-custom" concept, distinguishing the invention from fully patient-specific implants. The case may turn on how much, if any, patient-specific modification is permissible before the surface is no longer considered "non-custom."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim links the term to being "configured for engagement with standard size femoral bone cuts" (’150 Patent, cl. 1). This suggests the primary characteristic of "non-custom" is compatibility with standard surgical preparation, allowing for a broader reading that could tolerate minor patient-specific tweaks elsewhere on the surface.
- Evidence for a Narrower Interpretation: The summary of the invention describes the implant as having "a second portion including at least one standard feature" (’150 Patent, col. 2:36-37). The detailed description states the "inside geometry... can be selected from a standardized series of sizes, thereby allowing the use of standard instruments" (’150 Patent, col. 4:49-53). This language could support an argument that the entire inner surface must conform to a pre-existing, off-the-shelf standard design.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for the ’661 and ’399 patents. Inducement is based on allegations that Conformis provides surgeons with "associated surgical technique manuals" that instruct them on how to use the Accused Products in a manner that directly infringes the method claims (Compl. ¶¶ 24, 25, 54, 68). Contributory infringement is based on allegations that the patient-specific "iJigs" are especially adapted for use in the infringing methods and are not suitable for any other use (Compl. ¶¶ 65, 77).
- Willful Infringement: The complaint does not explicitly plead willful infringement. The allegations supporting knowledge for inducement state that Conformis has been aware of the ’661 and ’399 patents "since at least the filing of this complaint" (Compl. ¶¶ 64, 76). This phrasing appears to establish a basis for potential post-filing willfulness rather than pre-suit willfulness.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of process interpretation: For the method claims of the ’334, ’661, and ’399 patents, the dispute will likely focus on whether Conformis's integrated software design and manufacturing process, and the instructions provided to surgeons, perform the specific, ordered steps recited in the claims, or if there is a fundamental mismatch in the sequence or nature of the operations.
- A second key issue will be one of definitional scope: The viability of the infringement claims for the ’150 and ’936 "patient-modified" implant patents will hinge on the court's construction of "non-custom." The central question is whether an implant surface designed for standard surgical cuts but potentially having other patient-specific adaptations can still be considered "non-custom" within the meaning of the patents.
- A third question will be one of evidentiary proof for indirect infringement: For the method claims performed by surgeons, the case will depend on whether Zimmer can demonstrate that Conformis's instructions and user manuals specifically directed surgeons to perform all steps of the claimed methods, thereby establishing the requisite intent for inducement.