Abstract: A method for preparing a contact surface of an implantable bone, joint or similar prosthetic component subject to contact or motion includes the steps of mounting the prosthetic component on a turning or cutting machine and cutting the face of the prosthetic component with a diamond cutting tool using computerized control of tool position along a cross direction to machine cut a super finished surface. The variations of contour and the surface roughness are both under about 0.5 micrometers, and preferably under about 0.2 micrometers or less. The super finished surface generates wear particles at an asymptotically low or residual level during wear-in which may enhance wear characteristics and reduce local reaction or systemic rejection effects. The component is preferably formed by a strong hard polymer, such as UHMWPE.

Abstract: A bone prosthesis is provided which includes an implantable elongate stem member having a bore extending therethrough. The stem member has a proximal end and a distal end with at least one slot formed in the distal end. The slot extends along at least a portion of the stem member, in a longitudinal direction, from the distal end towards the proximal end to form at least two tines at the distal end of the stem. A bolt member is disposed within the bore of the stem member and has a proximal end and a distal end, wherein at least a portion of the bolt member proximate the distal end is threaded. An expander nut is disposed between the tines and is threadably matable with the distal end of the bolt member such that rotation of the bolt member in a first direction is effective to draw the expander nut towards the proximal end of the stem member to separate the tines at the distal end of the stem member.

Abstract: The present invention provides a knee prosthesis having a femoral component having a pair of spaced apart condylar portions and a boss structure extending between the condylar portions. The boss structure has a top surface that extends generally horizontally in a transverse plane and an opposed inferior surface. The knee prosthesis also includes a stem component having a proximal end and a distal end. The knee prosthesis further includes an attachment nut for securing the stem member to the femoral component.

Abstract: A modular joint prosthesis includes a tibial component formed of a tibial bearing insert and a tibial plateau. The tibial bearing insert is a modular component formed of a tibial insert body and a modular element. The tibial insert body and the modular elements are provided in a variety of geometries and sizes to yield various types of tibial insert bodies. The same tibial insert body may be used, for example, to form both rotatable and non-rotatable tibial bearing inserts.

Abstract: A prosthetic component which can be in the form of a hip stem (1) is provided with a proximal portion (2) and a distal portion (4) terminating at a distal end (5). The distal portion (4) has at least two slots (6) disposed longitudinally in the distal portion (4). The distal portion (4) of the hip stem (1) has a hollow centre (8). The hip stem (1) can be compressed to expand the diameter of the distal portion (4) by buckling the legs (13) between the slots (6) in the form of a stent or Chinese lantern.

Abstract: An acetabular cup having an outer surface elongated in a superior/lateral direction is effective to anatomically transfer load to the acetabulum and reduce the likelihood of bone fracture during implantation into the acetabulum. The outer surface has a first portion defined by a first radius and a second portion defined by a second radius. The second radius is offset from the first radius in superior and lateral directions to elongate the outer surface of the acetabular cup.

Abstract: An alignable orthopedic prosthesis system includes a prosthesis and an alignment guide. The prosthesis includes a stem having at least one slot extending along its length. The alignment guide has an alignment body with a guide surface extending from an end thereof, namely a key element formed as a blade for engaging and guiding the slot to orient the prosthesis stem. The alignment body also fits against a machined bone surface so that the blade is positioned in a plane that is oriented to guide the stem smoothly into contact with a recess formed in the bone.

Abstract: A device for limiting the flow of a fluid from a first region of a patient's body to a second region includes a primary passage for directing fluid from an inlet of the device to an outlet in response to the fluid flow rate being less than a predetermined level and a secondary passage for directing fluid from the inlet to the outlet in response to the flow rate being greater than or equal to the predetermined level. The secondary passage can be characterized as a tortuous flow path and presents a higher resistance to fluid flow than the primary passage. A detector is operative to close the primary passage in response to the flow rate reaching the predetermined level in order to force the fluid to pass through the secondary passage. With this arrangement, when the fluid flow rate reaches a level characteristic of overdrainage, the fluid is forced through the secondary passage in order to effectively reduce the fluid flow rate and prevent overdrainage.

Abstract: A catheter-based physiological pressure sensing device, which can be calibrated in vivo, is disposed in the distal end of a catheter, and is preferably in the form of a bulb-like device. The pressure sensing device includes a pressure sensor tip and pressure sensor element disposed in the pressure sensor tip. The pressure sensor element has first and second opposing surfaces which form separate and isolatable first and second chambers. An aperture is formed in an external wall of the pressure sensor tip to provide a passageway into the first chamber and expose the first surface of the pressure sensor element to a physiological pressure. A blocking element, such as a balloon, is disposed in the first chamber and is adapted for selectively blocking the aperture.

Abstract: A tool and a method for laying out resection or alignment features to prepare a bone end for prosthetic joint replacement. The tool includes adjustable assemblies coupled to a main body for determining a preparatory cut to fit a prosthesis, for example by drilling positioning holes or otherwise setting one or more preparatory cuts, and further includes elements for sizing the prosthesis. The body carries a sighting, pointer or caliper assembly which aligns to or is positioned on the medial and lateral epicondyles, and aligns the body along the epicondylar axis, while one or more other assemblies determine a line, depth or other positioning component to adjust the position of the body with respect to other landmarks before anchoring the assembly and performing cuts. In prototype embodiments, the body positions a drill guide to locate positioning pin holes in the femur.

Abstract: An implantable bone prosthesis includes portions of two different materials which interfit with each other to form a unitary article having hard wear surface portions and strong, stiff portions for structural support. These portions are preferably formed of ceramic and of metal, respectively. The prosthesis is formed by making a multiply connected ceramic wear surface element having openings or passages therethrough, and casting the remainder of the prosthesis extending in the openings to form a mating or dendritic support or a frame interdigitated and interlocked with the ceramic wear surface. The frame may be shaped so that it contracts along a direction of shrinkage, as the casting cools, without binding against the ceramic body. In a spherical shell, such as used for the weight-bearing acetabular shell or ball joint of a hip, this is achieved with short, radially-directed interlock elements.

Abstract: A proximally hollow prosthesis is provided having a cap element and a stem; the prosthesis, in one embodiment, has a cap element suitable to be adapted to a ball and hip socket and has a stem suitable to be implanted in a reamed femoral medullary canal. The stem of the prosthesis has a proximal region and a distal region and is mateable with the cap element of the prosthesis. The proximal region of the stem is open to define a cavity which extends longitudinally a predetermined distance through the proximal region of the stem but not into an isthmus region of the stem, which is located distal to the proximal region of the stem. The distal region of the stem is located distal to the isthmus region of the stem and is made of solid metal or alloys thereof. In another embodiment of the invention, the distal region of the stem is furcated, being at least bifurcated so as to define a plurality of tangs.

Abstract: A joint prosthesis system includes a tibial bearing insert, a tibial tray, a separate stabilizing post and a femoral component that are joinable to each other. The tibial bearing insert is mounted so that it can both rotate and translate with respect to the tibial tray. The stabilizing post and the femoral component cooperate to force roll back of the femoral component with respect to the tibial components.

Abstract: The present invention provides a femoral component of a modular knee prosthesis having a first condylar portion, a second condylar portion and a box structure having a radiused superior surface, an inferior surface, and an aperture extending therebetween. The box structure may be modular to accommodate varying femoral geometries. Pairs of opposing surface features, such as grooves, are formed on the box structure and allow for anterior-posterior positioning of a stem component such as a femoral stem, sleeve or sleeve adapter. Additional surface features may be provided to centrally locate the stem component.

Abstract: The present invention provides a jack device that is a body interposable between prosthetic joint components to provide a selectable spacing between them, and to thereby ensure that rotatably mated components are secured together in a selected angular orientation.

Abstract: A tool for preparing a bone end for prosthetic joint replacement. The tool rests on a resected end of one bone of an articulating joint set, and includes a jack assembly for supporting an opposing bone of the set in flexion while the bone ends remain attached together by ligaments. The jack pivotally supports the opposing bone and raises it to the spacing of the intended prosthesis to allow the surgeon to balance soft tissue tension. This support allows the bone to rotate under the tension of the connecting ligaments, into natural alignment while a template carried by the jack assembly lies against the prepared end, so subsequent cuts are in correct rotational alignment and the bone enjoys a natural posture when the joint components are attached.

Abstract: A joint prosthesis system includes first and second components that are joinable to each other in a manner to inhibit the rotation of the second component relative to the first component. The prosthesis system includes a rotation-inhibiting mechanism that has at least circumferential groove formed in one of a portion of the first component and a portion of the second component and at least one rib formed on the other of the first component and the second component. In one embodiment the rib may be eccentric, and the groove and the rib are matable with each other upon mounting of the second component within the first component.

Abstract: A shunt valve system includes an implantable shunt valve and a device for obtaining pressure setting information from the shunt valve after it is implanted under the scalp of a patient. The device includes a housing that is externally mountable on the patient's head proximate the shunt valve. A fluid-filled chamber is formed in the housing in which a ferromagnetic indicator is movable. The position of the ferromagnetic indicator corresponds to an indicator magnet located within the implanted shunt valve. In one embodiment, the indicator magnet is affixed to a cam which forms a portion of a stepping motor used to a select a pressure setting for the shunt valve. From the position of the ferromagnetic indicator, which corresponds to the indicator magnet and the cam, the pressure setting of the shunt valve can be determined.

Abstract: An implantable medical electrode supports at least one conductive contact having a rounded protrusion adapted for contacting a treatment site of a patient in use and an edge portion bordering at least a portion of the rounded protrusion. The electrode includes a first flexible insulating layer and a second flexible insulating layer having at least one aperture. In assembly, the conductive contact is positioned between the first and second insulating layers with the rounded protrusion of the contact aligned with, and extending into the aperture. In one embodiment, the rounded protrusion extends through the aperture to terminate at an apex beyond the second insulating layer.

Abstract: An orthopedic reaming instrument has an elongate member and a reaming member disposed on a distal end of the elongate member. The reaming member includes a distal apical region in the form of a partial sphere having an arc of less than 180.degree. and a proximal cylindrical region. An acetabular instrumentation system has an acetabular prosthesis in the form of a partial sphere having an arc of less than or equal to 180.degree. and an acetabular reamer which includes a distal apical region in the form of a partial sphere having an arc that is less than the arc of the prosthesis.