Abstract: A boring tool moves having a pitch orientation, a yaw orientation and a roll orientation and is steerable underground using the roll orientation. A maximum drill string curvature is established for steering. The boring tool is advanced over a path segment. An averaged roll characteristic is determined for movement of the boring tool along the path segment. A path segment pitch orientation is established based on at least one measured pitch orientation along the path segment. Using the maximum drill string curvature in combination with the averaged roll characteristic and the path segment pitch orientation, the yaw orientation is determined. The averaged roll characteristic is determined based on a series of incremental roll measurements that are spaced across the path segment. A set of coupled ordinary differential equations is used to characterize movement of the boring tool.

Abstract: A boring tool moves having a pitch orientation, a yaw orientation and a roll orientation and is steerable underground using the roll orientation. A maximum drill string curvature is established for steering. The boring tool is advanced over a path segment. An averaged roll characteristic is determined for movement of the boring tool along the path segment. A path segment pitch orientation is established based on at least one measured pitch orientation along the path segment. Using the maximum drill string curvature in combination with the averaged roll characteristic and the path segment pitch orientation, the yaw orientation is determined. The averaged roll characteristic is determined based on a series of incremental roll measurements that are spaced across the path segment. A set of coupled ordinary differential equations is used to characterize movement of the boring tool.

Abstract: An implantable orthopedic knee joint prosthesis. A femoral component has a first body including a surface for engaging femoral bone and a second body including a surface for engaging another component. Means are provided for hingedly connecting the first and second bodies together for relative pivoting motion about a fixed pivot axis. A tibial component has a baseplate that includes a surface for engaging tibial bone and a surface for engaging another component. An adapter bearing is disposed intermediate the second body and the baseplate and includes means for engagement with and affixation to the baseplate, and means for engagement with and affixation to the second body. A keel depends from the tibial bone engaging surface of the baseplate.

Abstract: A variety of surgical instruments facilitate implantation of a femoral stem component of an implantable prosthesis. A skeletal member is prepared by securing a reamer in the member. A broach is mounted on the reamer for broaching the member. A variety of adapters are selectively used with a head trial to check for location of the head trial. After trial placement is satisfactory, the instruments are removed so that the prosthesis can be implanted.

Abstract: A set of modular components from among which an implantable orthopedic hip prosthesis can be assembled. First and second implantable orthopedic femoral hip stem prosthesis each have a neck, the neck having a male conical taper surface. An implantable orthopedic femoral head prosthesis has a female conical taper surface. The respective male and female conical taper surfaces are sized and configured for mutual taper-locked interconnection if engaged, but at least one of the first and second implantable orthopedic femoral hip stem prosthesis is keyed in combination with the implantable orthopedic femoral head prosthesis to prevent engagement of the respective male conical taper surface with the female conical taper surface.