Abstract: A prosthesis implantation inserter is used with a flexible acetabular cup which has an opening or openings in its peripheral rim. The inserter has engagement elements which in an operational position frictionally engage the opening or openings in the flexible cup rim. A release is provided which can be operated to withdraw the engagement element from the opening or openings. When the cup is held §in position it can be guided and inserted into the acetabulum and impacted. Once the position of the prosthesis satisfies the surgeon the engagement element can be removed by operating the release and the cup inserter is removed without any risk of compromising the position or the stability of the implant.

Abstract: The ancillary tool according to the invention comprises a handle for manipulating an acetabulum provided, in its distal part, with a head for gripping the acetabulum and, in its proximal part, with a surface for application of a force of impaction. The tool further comprises at least one added endpiece adapted to be removably connected to the distal end of the handle. This endpiece defines both a face for wedging the acetabulum and an opposite face for interaction of the endpiece with the head of the handle, these faces both being borne by a radially deformable supple ring. The invention is particularly applicable to the positioning of an acetabular prosthesis in an anatomical or prosthetic cavity of a patient's hip.

Abstract: A computer aided surgery system, method, surgical method and instrument for guiding the positioning of an acetabular cup in a pelvis are described. The position of the transverse acetabular ligament of the pelvis and the position of the acetabular labrum of the pelvis are determined. The orientation of an acetabular plane including the acetabular labrum and the transverse acetabular ligament is calculated. A planned position for the acetabular cup is determined, in which an inlet plane of the cup is substantially parallel to the acetabular plane. The instrument comprises a mounting for attaching the instrument to a patient, a support, a guide defining a longitudinal axis, and for receiving a further instrument bearing the acetabular cup implant, and an adjustment mechanism. The adjustment mechanism can allow the angular orientation of the guide to be adjusted about at least two different axes to allow the inclination and version or anteversion of the longitudinal axis to be altered.

Abstract: A system and method for placing an implant into or onto supporting bone, or between adjacent bones, without impaction is disclosed. The system includes an implant, a distracter, and a sleeve. Optionally, the invention includes an alignment guide, a surgical navigational tracker, and a bone displacer. The sleeve is structured to interpose the implant and supporting bone and provide a differential engagement force between the sleeve-implant interface and the sleeve-bone interface to preferentially move the implant into, onto or between supporting bone structures.

Abstract: A T-shaped gauge and acetabular cup navigation system and acetabular cup aligning method using the T-shaped gauge, which can measure anantomical landmarks of the pelvis at the same time, calculate an anterior pelvic plane from the measured value, calculate a transformed anterior pelvic plane by converting the anterior pelvic plane in comparison with a pelvic reference frame, and set a direction vector of an acetabular cup on the transformed anterior pelvic plane, thereby exactly inserting the acetabular cup into the acetabulum without regard to movement of the pelvis.

Abstract: An ancillary tool and method for manipulating and implanting a prosthetic acetabulum including a tool provided, adjacent a distal part, with a head for interacting with an endpiece that is used for gripping the acetabulum and, in its proximal part, with a surface for application of a force along the handle. The endpiece is preferably removably connected to the distal end of the handle. The endpiece includes an elastically deformable ring having an outer face for expanding radially outwardly to initially grip the acetabulum and an opposite face for interaction with the head of the handle, such that upon a force being applied to drive the head into a cavity of the endpiece, the ring is radially expanded to expand the acetabulum in place after which the ring elastically returns to its original shape as the head is removed from the cavity.

Abstract: An acetabular cup shell inserter has a first end with a handle and a wire coupling element. The inserter has a shell insertion end opposite the first end having a radial expandable element for contacting an inner surface of the acetabular cup shell. A tubular portion is provided extending between the handle end and the insertion end. The tubular portion may be curved. A wire having a first end coupled to the coupling element at the first end is provided. The wire extends through the tubular portion and into the insertion end, the wire having a second end coupled to a moveable element for expanding the expandable element. The inserter includes a system for applying tension to the wire, such as by moving the wire in a direction towards the first end, the tension causing the expandable element to expand and grip the inner surface of the shell.

Abstract: A prosthetic ball and socket joint comprising a ceramic on ceramic articulation surface and a resilient bone interface coupling component.

Abstract: An improved acetabular impactor, especially suitable for use in minimally invasive hip surgeries, is disclosed. The impactor is simple in design and operation and spatially optimized. In particular, the impactor is designed to remotely detach the acetabular shell from the impactor via different potential mechanical connections.

Abstract: A short main incision and portal incisions at portal positions strategically displaced from the main incision are provided in a patient's hip. One portal incision (acetabular portal) provides for a disposition of reamers in the patient's acetabulum to shape the acetabulum. A cannula is inserted through the portal incision to the acetabulum and the successive reamers of progressive size are inserted into the acetabulum through the main incision to progressively size and shape the acetabulum. An approximately hemispherical acetabular component is then disposed in the prepared acetabulum to provide for hip rotation relative to the femoral component. The other portal incision (femoral portal) provides for insertion into the patient's hip of a member for driving the femoral stem into a cavity in the patient's femur. The provision of the short main incision and the portal incision minimizes the patient's loss of blood, tissue trauma, length of operating time and patient recovery time.

Abstract: A handling device to hold a bearing liner which is to be introduced into the socket of an acetabular cup has a support provided with an alignment element on the acetabular cup and having an opening which has a deformable rim adapted to receive the outer circumference of the bearing liner to be inserted. The bearing liner which may be, for example, conically tapered, is inserted into the opening in the support until the rim on the handling device is engaged. The held bearing liner can now be accurately located in a tapered socket of the acetabular cup utilizing the alignment device. Because the lower surface of the support rests against the upper rim of the acetabular cup, the complementary tapered bearing surfaces are not fully engaged. Engagement is achieved by pushing the bearing liner downwards through the deformable rim of the opening in the support so that the liner is correctly inserted. The handling device is now free of the bearing liner and can be removed.

Abstract: A short main incision and portal incisions at portal positions strategically displaced from the main incision are provided in a patient's hip. One portal incision (acetabular portal) provides for a disposition of reamers in the patient's acetabulum to shape the acetabulum. A cannula is inserted through the portal incision to the acetabulum and the successive reamers of progressive size are inserted into the acetabulum through the main incision to progressively size and shape the acetabulum. An approximately hemispherical acetabular component is then disposed in the prepared acetabulum to provide for hip rotation relative to the femoral component. The other portal incision (femoral portal) provides for insertion into the patient's hip of a member for driving the femoral stem into a cavity in the patient's femur. The provision of the short main incision and the portal incision minimizes the patient's loss of blood, tissue trauma, length of operating time and patient recovery time.

Abstract: A method and apparatus for performing minimally invasive hip surgery for implanting a prosthetic acetabular component into a natural acetabulum. The method and apparatus include a driving bit having one end connectable to an angled driving instrument and another end connectable to a screw-hole plug, dome plug, or bone screw. The driving bit has an elongated body with a length adapted for use in minimally invasive acetabular surgery.

Abstract: A CAS system and method for guiding an operator in inserting a femoral implant in a femur as a function of a limb length and orientation of the femoral implant with respect to the femur, comprising a reference tool for the femur, a registration tool, a bone altering tool and a sensing apparatus.

Abstract: The ancillary tool according to the invention comprises a handle for manipulating an acetabulum provided, in its distal part, with a head for gripping the acetabulum and, in its proximal part, with a surface for application of a force of impaction. The tool further comprises at least one added endpiece adapted to be removably connected to the distal end of the handle. This endpiece defines both a face for wedging the acetabulum and an opposite face for interaction of the endpiece with the head of the handle, these faces both being borne by a radially deformable supple ring.

Abstract: An acetabular component comprises a thin-walled, partial spherical body having an inner surface defining an articular surface and having angled recesses along an outer surface of the body for releasable engagement with an insertion and extraction tool. An insertion and extraction tool comprises a spring-loaded locking member movable from an extended position to a retracted position in response to relative sliding movement of an outer sleeve and inner shaft of the tool effected via an actuating force at a proximal end of the tool. The tool comprises engagement members insertable in the recesses when the locking member is retracted and, upon release of the actuating force, the locking member automatically returns to the extended position causing fingers of the locking members to enter the recesses and lock the acetabular cup to the tool.

Abstract: A method and apparatus for performing minimally invasive hip surgery for implanting a prosthetic acetabular component into a natural acetabulum. The method and apparatus include a posterior retractor having handle and retracting sections. The retracting section retracts soft tissue in the posterior section of the surgical site and includes a paddle with a curved flare and an elongated curved prong extending outwardly.

Abstract: A surgical tool for gripping the implant includes an elongate body having a first end surface for bearing on the prosthetic implant. Lugs or hooked ends of the tool are capable of attaching the tool to the implant.

Abstract: A modular implantation instrument for reliably positioning an acetabular prosthetic socket in the acetabulum of a pelvic bone during a total hip joint replacement surgery. The modular instrument has an interchangeable hemispherical ball member to properly engage into an acetabular prosthetic socket. A drive mechanism includes an alignment shaft member, operatively connected through an orientation pillar member to a levelling apparatus and to a laser pen apparatus. The modular instrument includes the hemipherical ball member is threadingly connected into the proximal end of said alignment shaft, the distal end of alignment shaft includes a handle and a knob. The lower end of said orientation pillar member is permanently attached to the shank of the alignment shaft member at angle of 135 degrees to the horizontal axis of said alignment shaft.

Abstract: The invention includes a method and system for intra-operative navigation of a joint replacement operation, without recourse to pre-operative imagery of pre-operative computerized simulations. Trackable markers and a locating system are employed to track first and second bones. A computer receives positional information regarding the trackable markers and calculates (predicts) at least one suggested combination of components of a modular implant system to produce a desired post-operative skeletal relationship.

Abstract: A cup for a hip replacement is disposed in a first relationship in an operating room with an object providing a sighting for the cup rotation in a first plane. The cup is thereafter rotated in the first plane through a first angle (e.g., 20°-30°). The cup is then disposed in a planar relationship in the operating room with another object providing a sighting for the cup rotation in a second plane transverse (e.g. perpendicular) to the first plane. The cup is subsequently rotated through a second angle (e.g. 40°- 45°) in the second plane. In this way, the cup is properly positioned in the acetabulum socket. The length of the leg receiving the hip rotation is then adjusted so that the leg length matches the length of the patient's other leg. This adjustment is provided without affecting the offset position of the center of the ball on the femur.

Abstract: The invention relates to a positioning instrument (1) for inserting an extension shell (2) into a human or animal bone, especially a pelvic bone. Said instrument comprises a fixing device (18) for fixing the extension shell (2) to the positioning instrument (1), and a displacement device (55) for displacing a disc element (15) of the positioning instrument (1) at least essentially axially in relation to the extension shell (2) fixed to the fixing device (18). Said disc element (15) co-operates with beveled surfaces (25a to 25e) of the extension shell (2) during the displacement, in order to tighten the extension shell (2). Furthermore, the disc element (15)-viewed in the direction of insertion (13)-does not project beyond the radially furthest projecting elements (32a, 32b) of the tightened extension shell (2).

Abstract: A modular implantation instrument for reliably positioning an acetabular prosthetic socket in the acetabulum of a pelvic bone during a total hip joint replacement surgery. The modular instrument has an interchangeable hemispherical ball member to properly engage into an acetabular prosthetic socket. A drive mechanism includes an alignment shaft member, operatively connected through an orientation pillar member to a levelling apparatus and to a laser pen apparatus. The modular instrument includes the hemipherical ball member is threadingly connected into the proximal end of said alignment shaft, the distal end of alignment shaft includes a handle and a knob. The lower end of said orientation pillar member is permanently attached to the shank of the alignment shaft member at angle of 135 degrees to the horizontal axis of said alignment shaft.

Abstract: A computer assisted orthopedic surgery planner software for generation of 3D (three dimensional) solid bone models from two or more 2D (two dimensional) X-ray images of a patient's bone. The computer assisted orthopedic surgery planner software reconstructs the bone contours by starting with a 3D template bone and deforming the 3D template bone to substantially match the geometry of the patient's bone. A surgical planner and simulator module of the computer assisted orthopedic surgery planner software generates a simulated surgery plan showing the animation of the bone distraction process, the type and the size of the fixator frame to be mounted on the patient's bone, the frame mounting plan, the osteotomy/coricotomy site location and the day-by-day length adjustment schedule for each fixator strut. All bone models and surgery plans are shown as 3D graphics on a computer screen to provide realistic, pre-surgery guidance to the surgeon.

Abstract: A surgical kit for minimally invasive total hip replacement includes a guide for inserting a guide wire into the body at the appropriate angle for reaming an Acetabulum. A shaft is inserted along the path of the guide wire. Working heads are sequentially attached to the shaft. The working heads of the reamers, impactors, trials and screw drivers are changed in the primary surgical incision thereby reducing the size of the incision and the trauma.

Abstract: A method and apparatus for performing minimally invasive hip surgery for implanting a prosthetic acetabular component into a natural acetabulum. The method and apparatus include a driving bit having one end connectable to an angled driving instrument and another end connectable to a screw-hole plug, dome plug, or bone screw. The driving bit has an elongated body with a length adapted for use in minimally invasive acetabular surgery.

Abstract: An acetabular prosthesis including a ceramic shell having multiple layers and a polymer liner formed integrally with the shell. The acetabular prosthesis shell is formed of a ceramic wherein several layers with varying porosities and thicknesses are sintered together to form a unitary structure. A polymer inner liner forms a bearing within the shell to receive the ball of a femur or femur prosthesis. The polymer liner is formed in the ceramic shell and includes a plurality of portions which interdigitate into the pores of the inner porous layer of the ceramic shell.

Abstract: An inserter includes a frame having a central bore through which a threaded rod is inserted, the threaded rod being used to secure the inserter to an object such as an implant. A thumbscrew is used to thread the rod into the object. A biasing member is located between the thumbscrew and a slider. A lever on the inserter is provided such that when the lever is closed, the slider is forced toward the thumbscrew, compressing the biasing member and generate opposing forces applied to the thumbscrew and slider. These opposing forces are transferred to the rod and frame and produce a resultant force that causes a compressive force to be exerted between the inserter and object. This resultant force firmly seats the inserter on the object and reduces the possibility that any blows applied to the inserter are diverted to the rod causing the rod to loosen or disengage.

Abstract: A pelvic alignment assembly and method for its use during a total hip replacement surgery in order to accurately reposition the patient's pelvis in a true anterior-posterior or true lateral position so as to optimize the accurate positioning of a prosthetic acetabular cup into the patient's hip joint socket. The assembly includes an elongated pin having one end anchored to the pelvis of the patient and a base removably inter-connected to the pin. A mounting member is movably connected to the base and is movable to adjust the relative positions of the base and mounting member in order to dispose an orientation indicator, such as a level structure, fixedly secured to the base, into a predetermined aligned or reference orientation.

Abstract: A surgical kit for minimally invasive total hip replacement includes a guide for inserting a guide wire into the body at the appropriate angle for reaming an Acetabulum. A shaft is inserted along the path of the guide wire. Working heads are sequentially attached to the shaft. The working heads of the reamers, impactors, trials and screw drivers are changed in the primary surgical incision thereby reducing the size of the incision and the trauma.

Abstract: The invention includes: a locating system; a computer, interfaced to the locating system and interpreting the positions of tracked objects in a generic computer model of a patient's hip geometry; a software module, executable on the computer, which defines the patient's pelvic plane without reference to previously obtained radiological data, by locating at least three pelvic landmarks; and a pelvic tracking marker, fixable to the pelvic bone and trackable by the locating system, to track in real time the orientation of the defined pelvic plane. Preferably, the system also includes a femoral tracking marker, securely attachable to a femur of the patient by a non-penetrating ligature and trackable by the locating system to detect changes in leg length and femoral offset.

Abstract: Conventional modular sockets for ball joint prostheses usually consist of a metal socket housing and a skid-type shell inserted in the housing. Ceramic skid-type shells are usually press-fitted in the socket housing. The socket housing may become stiff, thereby causing a migration of the generic sockets. If the skid-type shell is inserted improperly, material may chip off at the edge of the skid-type shell. Due to the various designs of sockets, skid-type shells with different outer diameter have to be made available for every gliding surface diameter. The invention provides for a ceramic skid-type shell (2) that is rigidly inserted into a biocompatible metal ring (5). Said ring (5) is provided with at least three radially outwards extending fixing elements (6). Said fixing elements (6) engage with respective recesses (8) in the socket housing (7). The ring (5) is spaced apart from the socket housing (7) by a gap (14).

Abstract: The invention relates to a prosthetic implant comprising a main body portion having a first surface for presentation to a receptive bone surface or into a bone cavity and a second surface for receipt of an articulating joint, and means on the implant adapted for attachment of a filamentary member, such as a cable. The invention also relates to a surgical tool for gripping the implant, comprising an elongate body having a first end surface for bearing on the prosthetic implant and means for attachment of the tool to the implant, directly or indirectly by means of the cable.

Abstract: An instrument for manipulating, detachably holding and placing an insert portion of a joint socket prosthesis into an outer shell of a said prosthesis. The instrument includes a handle and a holding tool. The holding tool includes two or more grasping claws which extend radially from the longitudinal axis of the handle over the insert, and serve to engage the insert to the holding tool. The handle is elongated and slideably positioned within a longitudinal bore or hole in the holding tool and typically includes a plunger. The insert is released when an operator causes the handle to slide within the holding tool towards the insert with sufficient force to disengage the insert from the grasping claws.

Abstract: A tool driver having a shaft with a longitudinal axis and opposite ends. A boss is secured at one of the shaft ends by which the tool driver is connected to a rotary tool. A tool collate is secured to the other of the shaft ends by which the tool driver may be driven by a surfical hand piece having a chuck in which the collate may be positioned. The boss is equipped with a securing device of the bayonet type having a latch mechanism which holds the rotary tool on the boss coaxially of the driver during use. The securing device has a tapered bore extending from the distal end of the boss axially of the shaft. The rotary tool has a diametral bar extending across a bottom tool driver opening with a centrally located circular disk therein. The disk of the rotary tool fits within the bore of the tool shaft boss so as to concentrically locate the rotary tool and the tool shaft on the same axis.

Abstract: An acetabular alignment method and apparatus utilize natural landmarks available on a pelvis to guide the alignment of an acetabular device in connection with the implant of a prosthetic hip joint at an implant site in the pelvis. The acetabular device is engaged with a positioning shaft having a longitudinal shaft axis, and locators are mounted upon the positioning shaft for placement adjacent selected landmarks on the pelvis to orient the shaft axis relative to the acetabular axis of a prepared acetabulum at the implant site in order to place the shaft axis at a prescribed angle of abduction and a prescribed angle of anteversion, thereby orienting the acetabular device at the appropriate angle of abduction and the appropriate angle of anteversion.

Abstract: A pelvic alignment assembly and method for its use during a total hip replacement surgery in order to accurately re-position the patient's pelvis in a true anterior-posterior or true lateral position so as to optimize the accurate positioning of a prosthetic acetabular cup into the patient's hip joint socket. The assembly includes an elongated pin having one end anchored to the pelvis of the patient and a base removably supported and attached to the opposite, outwardly extending end of the pin. The assembly also includes a mounting member movably connected to the base in a manner which enables the selective adjustment of the relative positions of the base and mounting member in order to dispose a level structure, fixedly secured to the base and movable therewith, into a horizontal position or other predetermined reference orientation.

Abstract: Methods and apparatus facilitate the positioning of a prosthetic element relative to a bone so as to achieve a desired orientation. An anchoring unit rigidly attaches to a point of the bone surrounding a region associated with receiving the prosthetic element, and at least one structural member is used to physically couple the prosthetic element to the anchoring unit. The combination of the anchoring unit and structural member includes one or more fasteners which may be loosened to temporarily remove the prosthetic element once a desired orientation is achieved, while facilitating re-installation of the element in accordance with the desired orientation following the temporary removal. In a preferred embodiment, the prosthetic element is an acetabular implant, and the surrounding bone forms part of a human pelvis. Regardless of the application, the element may take the form of a trial or a final implant.

Abstract: A method of implanting an acetabular cup which includes the step of preparing an acetabular socket to receive a cup, placing cement in the acetabular socket before or after locating a tube in line with the acetabular socket and inserting the acetabular cup through the tube and into the socket.

Abstract: An orthopaedic instrument for comparing post-surgical joint geometry to pre-surgical joint geometry. The instrument has a head chuck which can be secured to the ball of a ball joint, and an arm having reference indicia thereon. Markings indicative of the pre-surgical joint geometry are made on the bone with reference to the center of the ball. After replacement with a prosthetic ball, the post-operative geometry is verified by securing the head chuck to the prosthetic ball, and comparing the location of the bone markings against the reference indicia on the arm. As needed, adjustments are made in the prosthetic components.

Abstract: An alignment system 20 is used for alignment structure for surgical procedures. The alignment system and method can be used in a preferred embodiment to align an acetabular cup implant for purposes of a hip replacement procedure. The alignment system and method can be used for other alignment procedures whether or not an implant is utilized.

Abstract: A profile gauge for use with an acetabular cup loading tube provided with a skirt or flange characterized by adjustable means for measuring and indicating the diametric profile of the mouth of the rim area adjacent thereto of an acetabular socket into which an acetabular cup is to be implanted and includes means for removably locating said adjustable means on a loading tube to indicate on the skirt thereof the measured diameter profile.

Abstract: An acetabular cup extraction system includes a sealing member which is securable to an implanted acetabular cup. A elongate member is engagable with the sealing member to facilitate removal of the cup from the patient's acetabulum. In one embodiment, the sealing member includes a passage for coupling with a vacuum source to evacuate an interior portion of the cup and thereby enhance the engagement of the sealing member to the acetabular cup.

Abstract: An instrument (1) for the introduction of an inlay (E) of an implant, in particular of an artificial hip joint socket (HP), into the associated shell (S) of this implant, comprises a bar (2) which has a holder (5) at its distal end for holding the inlay (E) firmly. Furthermore, it comprises an actuating member (3, 30) for releasing the inlay (E) into the shell (S). The holder apparatus (5) comprises at least three resilient lamella (50) which point in the axial direction, are arranged in such a manner that their free ends point away from the bar (2) and are shaped in such a manner that they form a snap connection together with the inlay (E) when holding the inlay (E).

Abstract: Methods and apparatus facilitate the positioning of a prosthetic element relative to a bone so as to achieve a desired orientation. An anchoring unit rigidly attaches to a point of the bone surrounding a region associated with receiving the prosthetic element, and at least one structural member is used to physically couple the prosthetic element to the anchoring unit. The combination of the anchoring unit and structural member includes one or more fasteners which may be loosened to temporarily remove the prosthetic element once a desired orientation is achieved, while facilitating re-installation of the element in accordance with the desired orientation following the temporary removal. In a preferred embodiment, the prosthetic element is an acetabular implant, and the surrounding bone forms part of a human pelvis. Regardless of the application, the element may take the form of a trial or a final implant.

Abstract: Set of ancillary equipment for the implantation of acetabular cups (1) of hip prostheses, of the type having a substantially hemispherical corolla, consisting of expandable petals (2) which are provided with external barbs (5). The set comprises an obturator (7) for closing the petals, under elastic radial stress, in a position in which they are drawn together, elements (8, 9) for holding this obturator on the edges of the petals by connection with the bottom of the acetabular cup, an ancillary impaction device with which it is possible to impact the acetabular cup, freeing its petals by extraction of the obturator.

Abstract: A positioning tool has an elongated cylindrical section for reversibly engaging an acetabular cup which is insertable through a posterior opening in the cup. The outer diameter of a proximal portion of the cylindrical section is expandable to engage the inner wall of the cup in an interference fit to prevent movement of the cup relative to the tool and hold the cup in engagement with the tool to move the cup with movement of tool to place the cup for implanting at a desired position. The expanded portion of the tool may be contracted to release it from the cup after implantation. The proximal portion, which is attached to the distal portion and separated therefrom by a partial transverse slot, is divided into semicircular sections by a diametrical vertical slot therebetween. Diametrically opposite quadrants of the proximal portion further contain elongated slots therethrough which are perpendicular to the vertical slot and spaced from the edge of the cylinder by a thin section.

Abstract: Arrangement consisting of an acetabular cup prosthesis and of an implantation instrument for same. The acetabular cup prosthesis has at least one undercut holding recess in its edge end face. The instrument has a block which fits with centring into the opening or onto the opening edge of the acetabular cup prosthesis, and at least one holding projection positionally assigned to the holding recess and fitting into the latter, which holding projection is movable transverse to the opening direction, can be locked in a position in which it catches in the undercut of the holding recess, and can be withdrawn therefrom by means of an actuating member.

Abstract: An orthopaedic assembly includes a first portion or an acetabular cup and a second connecting portion or a cup inserter. The acetabular cup includes a cavity for receiving a femoral head and a pole defining a longitudinal axis through the cavity. The acetabular cup further includes an annular face which bounds the cavity and has a plurality of notches extending therein. Each notch includes an undercut wall. The annular face further includes a projection receiving device. A cup inserter includes a body with an end face and a plurality of fingers extending from the end face. Each finger is insertable into a corresponding one of the notches in a direction parallel to the longitudinal axis and is rotatable around the longitudinal axis to a locking position. Each finger includes a transverse surface which matingly engages with a corresponding one of the undercut walls when the finger is in the locking position. The cup inserter further includes a projection and a biasing device.

Abstract: A femoral head trial adaptor for converting a shell trial to a head trial includes a barrel member having an outer surface and an inner surface defining a cavity for receiving a femoral neck trial. A circumferential flange portion is located on the outer surface of the barrel member. A resilient connecting member disposed on the circumferential flange has a nominal first diameter compressible to a smaller second diameter in response to a force and returnable to the first diameter in the absence of the force for securing the trial adaptor to a shell trial. The flange may be located at a predetermined position along the outer surface of the barrel member so as to simulate a neck trial of a given length.