An intramedullary stem prosthesis includes a trunnion tapered in a first direction toward a proximal end of the intramedullary stem, and a conical shaft interfacing with the trunnion at a modular taper junction. The conical shaft is tapered in a second direction toward a distal end of the second component and has a proximal portion, a distal portion, and flutes positioned about a longitudinal axis of the conical shaft and extending along an entire length of the conical shaft and terminating at the modular taper junction such that the flutes intersect the modular taper junction. The proximal portion defines a first taper angle, the distal portion defines a second taper angle greater than the first taper angle, and the flutes define a major diameter of the conical shaft. The major diameter tapers at a major diameter taper angle that is constant along the entire length of the conical shaft.

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.

A connection arrangement (4, 4′) of two components (1, 2) according to the invention has a curved surface portion having a contact point on at least one of these components. The curved surface portion can extend over the entire surface of a groove, for example. The other component has a taper. When assembling the two components before a force is applied, a line connection is created from the 2-contact point connection and when force is applied, the line connection changes through plastic deformation into a strip connection, on the basis of which the two components (1, 2) hold together.

Apparatus and Method for Hip Surgery. An adjustable trial femoral head (400) for assessing anteversion of an acetabular cup relative to a pelvis of a patient are described. The adjustable trial femoral head comprises a spherical body (402) having a bore extending along a polar axis of the spherical body and configured to receive a free end of a femoral neck. A visual alignment guide (420) is mounted on the at least partially spherical body and the orientation of the visual alignment guide relative to the spherical body is adjustable.

A trial neck (30) and a method for trialling a neck of an orthopedic implant in a hip replacement procedure. The method includes inserting a broach (10) into a medullary canal of a femur and connecting a distal end of a trial neck to a proximal end (12) of the broach. The trial neck includes a proximal end connectable to a trial head. The trial neck includes a body portion extending along a neck axis (5) of the trial neck between the distal end and the proximal end. The proximal end includes a male connector for connection to a corresponding female connector of a trial head. The male connector includes a plurality of connection members (34A, 34B) extending parallel to the neck axis. The connection members are separated by one or more elongate slots (50) including at least one kink (52) forming an interlock between the connection members separated by that slot. The connection members are resiliently deflectable.

Hip tethering devices comprise a femoral implant including a housing that anchors the femoral implant to the femur, at least one spring, and a slider, such that the slider can move relative to the housing via compression and expansion of the at least one spring. A tether has a first end that anchors to the acetabulum, the tether passes through the femoral head, and a second end couples to the slider of the femoral implant, such that the tether spans across the patient's hip joint and relative motion between the slider and the housing allows a limited degree of separation of the femoral head from the acetabulum, while the at least one spring applies a variable tension load to the tether that resists separation of the femoral head from the acetabulum.

Femoral version impacts the long-term functioning of the femoroacetabular joint. Accurate measurements of version are required for success in total hip arthroplasties and hip reconstructive surgeries. An automated algorithm is provided for identifying the major landmarks of the femur. These landmarks are then used to identify proximal axes and create a statistical shape model of the proximal femur. With six proximal axes selected, and 200 parameters (distances and angles between points) from the shape model measured, the best-fitting linear correlation is found. The difference between true version and version predicted by this model was 0.00°±5.13° with a maximum overestimation and underestimation of 11.80° and 15.35°, respectively. This model and its prediction of femoral version are a substantial improvement over pre-operative 2D or intra-operative visual estimation measures. Acetabular orientation is also determined by an automated algorithm using radii of curvature measurements.

An orthopedic prosthesis mold, comprising a first housing including a first cavity therein shaped to form a portion of an orthopedic prosthesis; a second housing coupled to the first housing, the second housing including a second cavity therein shaped to form a portion of an orthopedic prosthesis, wherein the first and second housings are constructed from a material having a first hardness; a first shell element configured to receive at least a portion of the first housing therein; a second shell element configured to receive at least a portion of the first housing therein, wherein the first and second shell elements are constructed from a material having a second hardness greater than the first hardness; and a connection element releasably engageable to the first and second shell elements to prevent separation of the first shell element from the second shell element.

A hip prosthesis head includes: an external element with a convex external surface, and an internal element having a truncated-conical seat; wherein the external element and the internal element are made of different materials; the internal element is coupled in a blind hole of the external element in fit-in coupling mode; the external element has an annular base around the blind hole, and the internal element has a truncated-conical body that is open on the bottom, and an annular base that protrudes radially outwards from a lower edge of the body in order to be in contact with the base of the external element.

An orthopedic prosthesis includes a head which internally accommodates the major motion of a patient, e.g., during walking, thereby reducing wear against a cup or liner. A neck may be utilized which rotates within the distal member about an axis aligned with the major motion of the patient. The orthopedic prosthesis may also include a sacrificial anode, a seal made of natural fibers, and utilize lubricant made of honey.