Patent ID: 8801720

Claim:
A device for assisting in performing arthroplasty on a femur leg bone having a non-resected bone surface and a femoral mechanical axis, the device comprising: a first component comprising a mating region configured to matingly receive at least the non-resected bone surface in a single relative position, the mating region comprising a contacting surface that is an identical negative shape of the non-resected bone surface, wherein, when the mating region matingly receives the non-resected bone surface in the single relative position, the contacting surface makes surface contact with the non-resected bone surface; and a second component configured to mate with the first component to form a cutting instrument guide between the first component and the second component, the cutting instrument guide including at least one guide cutting planar surface that is generally perpendicular to the femoral mechanical axis when the non-resected bone surface is matingly received by the mating region.