Invalidity dossier
US 4936862
Method of designing and manufacturing a human joint prosthesis
Current assignee: Zimmer Technology Inc
Added 9/24/2026, 2:03:40 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US4936862A
Title: Method of designing and manufacturing a human joint prosthesis.
Inventors/Assignee: Peter S. Walker and Frederick C. Ewald; current assignee listed as Zimmer Technology Inc. (original assignee: Individual).
Key dates: Prior art date 1986-05-30; application US07/188,477 filed 1988-04-29; granted and published 1990-06-26; status expired (anticipated expiration 2007-06-26).
Purpose: To develop a method for designing and evaluating a prosthesis combining all significant elements on a given side of a human joint for maximum geometric compatibility with the recipient's supporting bone, enabling press-fit implantation, sufficient stability to induce a stable biologic interface, and maximum bone ingrowth.
Plain-language scope: The method first builds a three-dimensional model of an "average" joint bone, including exterior surfaces and the cortical canal, from a statistically significant sample and a piecewise mathematical analog. Sections may be obtained by slicing embedded cadaver joints into closely spaced segments (e.g., 25) or by CT scan, digitized (e.g., 30–40 points per section), and averaged across corresponding levels. The patient's corresponding bone size and shape is then determined by tomography or radiographs taken in fixed anterior-posterior, lateral-medial, and longitudinal axes. Measured dimensional relationships between the patient's bone and the stored average bone (scaled to the patient) are input to the computer, which generates a three-dimensional shape representing the average bone distorted to conform to the patient's principal contours and dimensions. The resulting design is thus a synthesis of the average bone fitted to the individual, intended to allow anatomic press-fit, optional downsizing for cemented fixation with a uniform mantle relative to cortical bone, and economical customized fit.
Source: https://patents.google.com/patent/[US4936862](/patent/US4936862)/en
What the excerpt does not establish: It omits much of the specification and all claims; therefore claim scope, claim language, the full manufacturing steps, and the specific figures/embodiments are not established here. Dates and assignee are as listed by the source and are assumptions, not legal conclusions. No litigation, ownership-transfer detail, validity, or prior-art analysis is presented or relied upon.
Generated 10/1/2026, 9:30:55 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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