In one aspect, a system and method for aligning hip replacement prostheses comprises an acetabular liner having an inner concave surface and an outer convex surface. The acetabular liner includes at least two magnetic sensors arranged in a spatially distributed manner. The system and method also include a prosthetic femoral component comprising a femoral head component. The femoral head component and the acetabular liner component are shaped such that a ball and socket joint is formed when the femoral head component comes into contact with the inner concave surface of the acetabular liner. While the ball-and-socket joint is formed, and in at least some orientations of the femoral head component relative to the acetabular liner component, a contact point on an external surface of the femoral head component contacts the inner concave surface. The femoral head component includes at least one permanent magnet.

A hip/shoulder prosthesis includes: a head component; a metaphyseal component; a diaphyseal nail, and a locking device. The head component includes: a front face and rear face; with a bore, and first and second shaped recesses in the rear face. The metaphyseal component includes: a central transverse aperture at an angle to the metaphyseal component's axis; a first end configured for threaded engagement within the bore of the head component; and a longitudinal hole that begins at the second end, transects the transverse aperture and reaches the first end, to receive the locking device. The diaphyseal nail is inserted in the femoral or humeral canal, and includes: fastening apertures that receive corresponding screws for fastening the diaphyseal nail to the femur or humerus; a portion configured to be received within, and engage, the transverse aperture of the metaphyseal component, and a transverse hole configured to receive the locking device.

Disclosed embodiments pertain to systems to intraoperatively determine prosthetics (such as femoral stems) or a combination of prosthetics (such as a femoral stem used in combination with other prosthetics) that meet target parameters (such as leg length). The system may determine, for a patient, a plurality of leg lengths, where each leg length may correspond to a distinct digital prosthetic template in a set of digital prosthetic templates, and where each digital prosthetic template may be associated with a distinct prosthetic in a set of prosthetics. In response to a received target leg length for the patient, the system or method may determine prosthetics that when implanted in the patient would yield the target leg length and may display corresponding prosthetic information. The target length may be input using slider on a graphical user interface and the system may interactively update the prosthetics that would yield the target leg length.

A prosthesis alignment guide includes a guide body that has an opening that extends at least partially therein and a first alignment hole extending entirely therethrough. The opening is configured to receive a trunnion of a joint prosthesis for mounting the guide body to the joint prosthesis. An alignment member is disposed within the first alignment hole and is axially moveable therein. A locking member is engaged to the guide body and moveable from a first position in which the locking member is disengaged from the alignment member and a second position in which the locking member engages the alignment member and secures it from axial movement within the first alignment hole.

This invention corresponds to a prosthesis for total or hip resurfacing replacement, which comprises a prosthetic femoral head made of highly cross-linked polyethylene, with a diameter ranging from 38 mm to 64 mm, to articulate with a cup or acetabular component made of metal. When the invention applies to total hip replacement, the polyethylene head includes a metal core, which contains inside the female counterpart (14) to mate with the male counterpart (13) of a Morse taper, located at the upper end of the femoral component. The use of this type of head for total hip replacement, articulated with an ultra-polished acetabular cup, reduces the risk of dislocation, transmits less angular and torque forces to the Morse taper than large metal heads, and avoids the problems related to the metal-metal bearing or with the use of large metal heads with thin polyethylene. When the invention relates to hip resurfacing replacement, the highly cross-linked polyethylene femoral head has a lower polyethylene extension or stem with or without internal metal reinforcement (151) or a metal stem integrated into a metal-back (152). Using these types of heads for hip resurfacing replacement heads eliminates the problems associated with metal-on-metal resurfacing replacements.

A system and method for improving assembly of a modular prosthesis, particularly a femoral stem. The system and method may include implementation of assembly systems for modular prosthesis having one or more intermediate components between a pair of “end components” such as a stem and a head. Grip structures are provided on non-aligned assembly axes and holders are used for each phase to engage appropriate grip structures for joinder of components having aligned assembly axes.

Provided is an artificial joint that can improve fatigue strength while achieving the ability to fix to a bone. An artificial joint 1 includes a stem portion 2. The stem portion 2 has a distal end for insertion into a bone and a proximal end opposite the distal end and includes a roughened surface portion 4 which is provided in a proximal end-side portion, which has a rougher surface than a distal end-side portion, and which is larger in cross-sectional area than the distal end-side portion. The roughened surface portion 4 includes a distal end-side edge section 7 and a proximal end-side section 7, the distal end-side edge section 7 including a distal end-side edge portion of the roughened surface portion 4, the proximal end-side section 7 being configured as a section closer to the proximal end than the distal end-side edge section 7 is to the proximal end. The distal end-side edge section 7 has a surface roughness Ra1 lower than a surface roughness Ra2, Ra3 of the proximal end-side section.

A joint replacement implant may include a shaft having a proximal end, a distal end, and a threaded shaft portion, a helical thread disposed about the shaft defining a length of the threaded shaft portion and including a concave undercut surface angled towards one of the proximal end and the distal end of the shaft, and an attachment feature at the proximal end of the joint replacement implant. The attachment feature may be configured to couple an articular member to the joint replacement implant. The articular member may include at least one artificial articular surface that may be shaped to replace at least a portion of a natural articular surface of a joint of a patient.

A femoral head prosthesis is a multilayer composite having a metal neck stem component thread or press fit into a hollow rigid shell of metal or ceramic, a polymeric core filling the interior volume under the hollow rigid shell and around a forward part of the neck stem, and a smooth, void-free polymeric articulation layer of at most 12 mm over the exterior of the shell. The prosthesis is formed by a polymeric molding process wherein polymerizing resin or heated thermoplastic material is flowed in a mold through a set of holes through the hollow shell into the interior volume and around the shell's exterior. Once the resin has cured or the thermoplastic cooled, the stem, core, shell and articulation layer collectively form an integral prosthesis of a desired head diameter matching a patient's anatomy.

A femoral trialling kit and method for assessing acetabular cup orientation during a left hip joint surgical procedure and a right hip joint surgical procedure are described. The kit includes a trial femoral head (104, 414, 514, 614, 814) having an inner wall defining a cavity extending along a head axis and a visual alignment guide on an outer surface of the trial femoral head and a trial femoral neck (126, 412, 512, 612, 812) having a taper at a free end, the taper being receivable within the cavity. One of the taper and the inner wall has a first anti-rotation feature (684, 698) and a second anti-rotation feature (686, 700), the first anti-rotation feature and the second anti-rotation feature being inclined, and the other of the taper and the inner wall has a third anti-rotation feature (702). The trial femoral head is attachable to the trial femoral neck in a first angular configuration corresponding to a right hip joint, in which the third anti-rotation feature and the first anti-rotation feature engage, and a second angular configuration corresponding to a left hip joint, wherein the third anti-rotation feature and the second anti-rotation feature engage.