PTAB

IPR2017-00544

Smith & Nephew Inc v. ConforMIS Inc

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1. Case Identification

2. Patent Overview

  • Title: Method for Making a Surgical Tool
  • Brief Description: The ’263 patent discloses methods for making patient-specific surgical tools for joint arthroplasty. The method involves obtaining image data of a joint (e.g., MRI or CT), deriving the uncut cartilage surface, and creating a tool with a contact surface that is a negative of the cartilage, along with guides for surgical instruments to ensure proper implant orientation.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 6-19, 21-23, 25, 27, 28, 31-34, 36-39, 45-46, and 49 are obvious over Radermacher and Alexander.

  • Prior Art Relied Upon: Radermacher (WO 93/25157) and Alexander (WO 00/35346).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued Radermacher taught nearly all elements of independent claim 1. Radermacher disclosed using MRI/CT data to create an "individual template" for orthopedic surgery with a patient-specific contact surface and guides for cutting and drilling. Petitioner contended that Radermacher’s disclosure of creating a negative mold of the "individual natural (i.e. not pre-treated) surface" inherently taught matching the tool to the articular cartilage, as cartilage is part of the natural, untreated joint surface. Alexander was cited to explicitly teach using MRI to generate a 3D image and map of a patient’s cartilage surface for therapeutic planning, including joint replacement surgery. Petitioner asserted that Alexander's teachings made it explicit that the cartilage surface could be derived from image data.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because both addressed patient-specific treatments for knee joints using MRI technology. Petitioner argued a POSITA would be motivated to apply Alexander's specific cartilage imaging techniques to Radermacher’s surgical template to improve the template's fit and accuracy. This would simplify the surgical procedure by allowing the template to be placed directly on the untreated joint, including any remaining cartilage, rather than requiring cartilage removal prior to placement.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because combining the known technique of cartilage imaging (Alexander) with the known technique of creating patient-specific guides (Radermacher) involved applying predictable technologies to achieve a predictable improvement in surgical efficiency and accuracy.

Ground 2: Claims 1-3, 6-19, 21-23, 25, 27, 28, 31-34, 36-39, 45-46, and 49 are obvious over Radermacher and Fell.

  • Prior Art Relied Upon: Radermacher (WO 93/25157) and Fell (WO 00/59411).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative to Ground 1, substituting Fell for Alexander to supply the explicit teaching of deriving an articular cartilage surface from MRI data. Petitioner argued Fell disclosed using MRI to create contour plots of the femoral condyle and tibial plateau, "complete with articular cartilage," for the purpose of creating a patient-specific meniscal implant. The core teachings of Radermacher regarding the patient-specific template with guides were applied in the same manner as in Ground 1.
    • Motivation to Combine: The motivation was similar to Ground 1, as both references were in the field of patient-specific orthopedic devices for the knee using MRI. Petitioner additionally argued that Radermacher itself provided motivation by stating that individualized surgical procedures were "lagging behind the technology of implant manufacture." This would have prompted a POSITA to adapt advanced patient-specific implant technology, like that taught in Fell, to the creation of surgical guides as taught by Radermacher.
    • Expectation of Success: Success was expected because it involved the straightforward application of Fell's established cartilage imaging method to Radermacher's surgical guide concept, a simple substitution of one known imaging target for another.

Ground 3: Claims 20, 24, and 26 are obvious over the references in Grounds 1 or 2 and further in view of Woolson.

  • Prior Art Relied Upon: Radermacher, Alexander or Fell, and Woolson (Patent 4,841,975).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed dependent claims requiring alignment relative to a biomechanical axis (claim 26) and imaging of more than one joint (claim 20). Petitioner argued that Woolson taught determining the mechanical axis of the leg for knee replacement surgery by imaging both the knee and ankle joints via CT scans. Woolson explained that aligning implants to this axis was critical for the long-term success of the procedure. For claim 24, which added common surgical tools like spacers, Petitioner argued Woolson taught their conventional use.
    • Motivation to Combine: A POSITA would combine Woolson’s teachings on biomechanical alignment with Radermacher’s patient-specific guide because proper alignment was a fundamental, well-known goal in all knee arthroplasty. Applying Woolson's technique to Radermacher's system was a predictable way to improve the surgical outcome by ensuring the cuts planned and executed with the custom guide were correctly oriented with the patient's overall leg mechanics, not just the local joint anatomy.
    • Expectation of Success: The combination was a routine and necessary step for any state-of-the-art knee replacement system. Integrating alignment calculations into a computer-planned surgical guide was a well-understood and predictable process for a POSITA.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including: (1) claims 40-43 over Grounds 1/2 in view of Woolson and Hofmann for adding a predetermined tibial cutting slope; and (2) claims 44 and 47-48 over Grounds 1/2 in view of Biscup for adding the step of using image data to select or generate the implant itself.

4. Relief Requested

  • Petitioner requests that the Board institute an inter partes review and cancel claims 1-3, 6-28, 31-34, and 36-49 of the ’263 patent as unpatentable.