Modifying the geometry of elements in a prior art design to accommodate objects of varying sizes is generally within the scope of routine skill possessed by an ordinary person. Physical combinability is not required for a finding of obviousness when the necessary adaptations involve no more than the predictable use of prior art elements according to their established functions.
Background / Facts: The patent on appeal here from inter partes reexamination at the PTO is directed to a system for using plates to repair bone fractures in long bones, such as the femur. The bone plate runs along the outside of the fractured bone and is attached by bone anchors (typically, bone screws) that are inserted through predrilled holes in the plate and then into the bone. Bone screws come in two basic forms: compression (non-locking) screws to draw the bone and the plate together for fracture reduction and quicker healing, and locking screws to fix the relative position of the plate and bone so that the plate does not move relative to the bone. The disputed claim limitation relates to the structure of the holes in the plate through which the screws are inserted, with the claimed design having all of the holes in the plate’s head portion conically tapered and at least partially threaded so as to be capable of engaging both types of screws. This provides added flexibility for surgeons, who can choose to use either locking screws or compression screws in each of the threaded holes depending on whether compression or stabilization is preferred at that particular position. The prior art similarly teaches conical, partially threaded holes but it appears that, in the prior art’s particular design, using a standard compression screw in those holes would cause the screw to protrude above the line of the plate and lead to undue discomfort by the patient.
Issue(s): Whether it would have been obvious to modify the plate hole geometry disclosed in the prior art to better accommodate screws of both types in the manner claimed in order to provide the same flexibility to surgeons during an operation.
Holding(s): Yes. The court found that “[t]he Board’s observation that the chamfer in [the prior art’s design] is narrow ignores the point that the disclosure of a chamfer is not limited to the precise size of the chamfer depicted in the illustration of the [prior art] device. Chamfers are conventional features in the art and can be sized to accommodate screw heads of varying heights. Nothing about the [prior art] reference limits the size of the chamfer or in any way suggests that it could not be made larger than it appears to be in the drawings contained [therein].” Quoting KSR, the court concluded that “[t]his case is therefore one that falls within the Supreme Court’s characterization of obviousness as entailing an improvement that is no ‘more than the predictable use of prior art elements according to their established functions.’”