PTAB

IPR2017-00511

Smith & Nephew Inc v. ConforMIS Inc

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Patient-Specific Surgical Instruments and Methods of Use
  • Brief Description: The ’158 patent relates to methods for creating patient-specific surgical instruments for orthopedic procedures. The methods use a first set of image data (e.g., CT or MRI) to derive a patient-specific surface for the instrument and a second, different type of image data (e.g., X-ray) to determine the orientation of a surgical guide on the instrument.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 66-72 and 81 over CAOS, Woolson, and Alexander

  • Prior Art Relied Upon: CAOS (a 1998 article on computer-assisted orthopedic surgery), Woolson (Patent 4,841,975), and Alexander (WO 00/35346).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination teaches all key limitations of the challenged claims, particularly independent claims 66, 69, 72, and 81. The central assertion was that CAOS disclosed creating patient-specific "individual templates" with surfaces that precisely fit a patient's bone, based on a first image data set like CT or MRI. CAOS also disclosed using a second image data set (topograms) to identify the "bone axis" for aligning tool guides. Petitioner asserted that Woolson taught the well-known and critical practice of using X-ray image data to determine a patient's mechanical axis and orienting cutting guides perpendicular to that axis to ensure proper implant alignment. Petitioner contended that substituting Woolson's use of X-rays for CAOS's topograms would have been an obvious design choice for a POSITA, as both are 2D radiographic images used for the same alignment purpose. To address claim limitations requiring the patient-specific surface to match a joint's cartilage, Petitioner introduced Alexander, which taught using CT or MRI to generate a complete model of a patient's knee joint, including both bone and cartilage surfaces.
    • Motivation to Combine: A POSITA would combine CAOS and Woolson to integrate the benefits of two established techniques: a precisely fitting instrument (from CAOS) that is also accurately aligned with the patient's crucial mechanical axis (from Woolson), a combination essential for long-term surgical success. The combination was presented as a straightforward application of known methods to improve a known device. A POSITA would further incorporate Alexander's teachings to create a more accurate patient-specific surface that accounts for cartilage, representing a simple choice from a finite number of predictable solutions (matching bone, cartilage, or both).
    • Expectation of Success: Petitioner argued that the combination involved applying known imaging and surgical planning techniques to the same field of knee arthroplasty, using each for its intended and well-understood purpose. This would have resulted in a predictable and successful outcome.

Ground 2: Obviousness of Claims 73-80 over CAOS, Woolson, Alexander, and Radermacher

  • Prior Art Relied Upon: CAOS, Woolson, Alexander, and Radermacher (WO 93/25157).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground challenged method-of-use claims, which include steps of placing the instrument, cutting or drilling tissue, and implanting an orthopedic implant. Petitioner argued that the combination of CAOS, Woolson, and Alexander taught the patient-specific instrument itself, as detailed in Ground 1. Radermacher, whose lead author is the same as that of CAOS, was added to explicitly teach the claimed surgical method steps. Petitioner asserted that Radermacher disclosed the entire process: creating a patient-specific "individual template" from CT/MRI data, using the template's guides to drill holes and make cuts to prepare a bone surface, and subsequently seating an implant onto that prepared surface. The combination thereby taught not only the claimed instrument but also the claimed method of using it to perform knee arthroplasty.
    • Motivation to Combine: A POSITA would combine the instrument taught by CAOS/Woolson/Alexander with the surgical method taught by Radermacher because Radermacher disclosed the intended purpose and explicit method of use for the very type of patient-specific template taught in CAOS. Since the references address the same problem in the same field, combining them represented using the tool for its clearly described and intended function.
    • Expectation of Success: Radermacher explicitly described a complete and successful surgical workflow using these types of patient-specific tools. Therefore, a POSITA would have had a very high expectation of success in applying the method taught by Radermacher using the instrument taught by the primary combination.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 66-81 of the ’158 patent as unpatentable under 35 U.S.C. §103.