Patent Description:
The systems and methods described herein are directed to orthopedic implants, for example to reverse shoulder replacement systems and methods for implantation.

Shoulder replacement surgery involves placing a motion providing device at the glenohumeral joint, i.e., the joint interface between the scapula and the proximal humerus of the arm. Reverse shoulder replacement reverses the curvature of the natural glenoid cavity and the proximal head of the humerus. That is, a convex surface of a glenoid component is positioned on the scapula and a concave surface of a humeral component is positioned on the proximal humerus.

Some reverse shoulder systems have limitations in connection with the fixation of the glenoid component. In some glenoid component designs, a one-piece construct is provided in which a central threaded post projects from a baseplate. The threaded post provides fixation to the bone of the scapula, but provides little to no flexibility of the final positioning of peripheral features of the baseplate, such as screw or mount holes thereon. Also, the unitary nature of this approach requires more inventory to provide a proper mix of baseplate configurations and threaded post sizes.

Other reverse shoulder systems provide a plate having an integral fixed central post and a plurality of screws that are placed through either the post or the plate. These systems are limited in that the length, inner diameter, and configuration of the central post are fixed. As such, the size of a screw placed through the central post is predefined which limits the ability to perform revisions (subsequent surgeries on the patient to replace the system). In a revision surgery the old implant must be removed and replaced with a new implant. Commonly a substantial amount of bone is removed with the old implant and in this case larger screws are required to securely fix the new glenoid implant to the scapula.

In currently available systems, specifically unitary systems having an integral fixed central threaded post, independent rotation is not provided between the post and the baseplate. For these unitary systems the post and the baseplate rotate together when the post is driven into the bone. With other glenoid implants wherein an anchor member is driven through the baseplate and extends from a distal end of the baseplate, axial translation of the baseplate relative to the anchor member is not prevented. For these systems, the baseplate is not secured against axial translation until the anchor member is fully engaged in the scapula and pulls the baseplate against the surface of the bone thereby preventing rotation of the baseplate. An example of such a glenoid component is provided by <CIT> in which a bone engaging member is therethrough provided with a central bore having an internal threading at its distal end: in order to secure the bone engaging member with the scapula, an anchor is inserted into the proximal end of the central bore, then moved forward into the central bore so as to protrude from the distal end of the central bore to be progressively anchored into the bone, until a threaded proximal head of the anchor screws into the distal internal threading of the central bore.

There is a need for new shoulder prosthesis systems that can provide more flexibility and better adaptability to patient anatomies while maximizing revision options. When implanting reverse shoulder systems it is desirable to independently attach a baseplate to the scapula and thereafter to independently rotate the baseplate with respect to the scapula such that fixation means in the periphery of the baseplate can be driven into bone thereunder.

For this purpose, the invention is a glenoid implant for a shoulder prosthesis as defined in claim <NUM>. A glenoid implant, according to some embodiments disclosed herein, includes an anchor member and a baseplate. The anchor member has a longitudinal portion configured to be secured to a bone and a proximal head. The proximal head has a first engaging surface. The baseplate has a proximal end and a distal end. The distal end of the baseplate comprises a first aperture sized to accept the proximal head of the anchor member and a second engaging surface. When the proximal head is inserted from the distal end of the baseplate into the first aperture, the first engaging surface couples with the second engaging surface. The anchor member is restrained against axial translation by this engagement with respect to the baseplate but is permitted to rotate with respect to the baseplate.

Other embodiments of a glenoid implant may further comprise a locking structure configured to apply a force to the anchor member. A glenoid implant may further comprise a glenosphere configured to be attached to the baseplate. A glenoid implant may also include one or more perimeter anchors for securing the baseplate to bone.

A method for implanting a glenoid implant, which does not form part of the claimed invention, includes providing an anchor member and a baseplate. The anchor member has a longitudinal portion configured to be secured to a bone and a proximal head. The proximal head has a first engaging surface. The baseplate has a proximal end and a distal end. The distal end of the baseplate comprises a first aperture sized to accept the proximal head of the anchor member and a second engaging surface. The method includes securing the anchor member at least partially to bone. The method further includes, with the proximal head of the anchor member inserted into the first aperture such that the first engaging surface is coupled to the second engaging surface, rotating the baseplate relative to the anchor member to adjust the position of the baseplate without adjusting the rotational position of the anchor member. The method may further include securing the baseplate to the bone.

In some aspects, a method further comprises, prior to securing the anchor member at least partially to bone, inserting the proximal head into the first aperture to cause the first engaging surface to couple with the second engaging surface. A method may also comprise applying a force to the anchor member with a locking member to prevent rotation between the anchor member and the baseplate. A method may also comprise engaging a glenosphere to the baseplate. In some embodiments, securing the baseplate to bone comprises inserting one or more perimeter anchors through one or more openings in the baseplate.

Here are also disclosed additional implants or components of implants, as well as further methods, which does not form part of the claimed invention. A system or kit that does not form part of the claimed invention may also be provided, wherein the system or kit comprises a plurality of anchor members engageable with one or more baseplates and/or a plurality of baseplates engageable with one or more anchor members, examples of which are described further herein.

In other embodiments, a glenoid implant for a shoulder prosthesis is formed. The glenoid implant comprises an anchor member and a baseplate. The anchor member has a longitudinal portion configured to be secured to a bone and a proximal head. The proximal head has an external threaded surface. The baseplate has a proximal end and a distal end. The distal end has a first aperture sized to accept the proximal head of the anchor member. The first aperture has an internal threaded surface and a space disposed proximal of the internal threaded surface. When the external threaded surface of the proximal head is disposed proximal of the internal threaded surface of the first aperture, the anchor member is restrained against axial translation with respect to the baseplate but is rotatable with respect to the baseplate.

In another embodiment, a glenoid implant for a shoulder prosthesis is provided that includes a baseplate, an internal member, and a screw. The baseplate has a proximal end, a distal end, an outer periphery, and an aperture that extends therethrough adjacent to the outer periphery. The aperture extends from the proximal end to a bone engaging surface. The internal member disposed in the baseplate has an internal threaded surface surrounding the aperture. The screw is configured to be placed through the aperture. The screw has an external threaded surface. A first number of thread starts disposed on the internal threaded surface of the internal member is greater than a second number of thread starts disposed on the external threaded surface of the screw. The threads of the external threaded surface of the anchor member have a constant thread form along the length thereof.

These and other features, aspects and advantages are described below with reference to the drawings, which are intended to illustrate but not to limit the inventions. In the drawings, like reference characters denote corresponding features consistently throughout similar embodiments. The claimed invention is shown by the <FIG>. The following is a brief description of each of the drawings.

While the present description sets forth specific details of various embodiments, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting. Furthermore, various applications of such embodiments and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described herein. Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.

<FIG> depicts the human shoulder. The glenoid cavity is a portion of the shoulder that is located on the scapula. The glenoid cavity articulates with the head of the humerus to permit motion of the glenohumeral joint. Total shoulder arthroplasty replaces the glenohumeral joint with prosthetic articular surfaces that replicate the naturally occurring concave and convex surfaces of the body. Typically, in total shoulder arthroplasty, an articular surface replaces the humeral head and an articular surface replaces cartilage in the glenoid cavity. In a typical reverse total shoulder arthroplasty, a glenoid implant with a convex spherical head is inserted into the glenoid cavity and a complimentary socket is placed on the humerus. Reverse total shoulder arthroplasty reverses the naturally occurring ball and socket orientation related to the glenohumeral joint.

<FIG> depict a glenoid implant <NUM>, more preferably a reverse glenoid implant, configured to be implanted in the glenoid cavity of a patient in the patient's scapula. The glenoid implant <NUM> includes an anchor member <NUM> for anchoring the implant <NUM> in the scapular glenoid, a baseplate <NUM>, a locking structure <NUM> configured to deter rotation of the anchor member relative to the baseplate, and a glenosphere <NUM> having an articular surface (e.g., a convex, spherical surface). The glenosphere <NUM> is configured to couple to a complimentary prosthetic device anchored to the humerus (not shown, but sometimes referred to herein as the humeral component) in order for the joint replacement implants to replicate the motion of the human shoulder. The humeral component can take any suitable form such as those disclosed in connection with Figures <NUM>-<NUM> and elsewhere in <CIT>. Suitable humeral components can be configured to couple with reverse shoulder joint components, including those described in connection with <FIG>, <NUM>-<NUM>, and <NUM>-<NUM> of the '<NUM> application. Suitable humeral components can be configured to adapt to anatomical and reverse shoulder configurations. The glenoid implant <NUM> and the humeral component provide a replacement for the natural glenohumeral joint.

As used herein, the terms "distal" and "proximal" are used to refer to the orientation of the glenoid implant as shown in <FIG>. As shown in <FIG>, a longitudinal axis <NUM> of the glenoid implant <NUM> extends through a central longitudinal axis <NUM> of anchor member <NUM> (shown in <FIG> and <FIG>). The glenosphere <NUM> is towards the proximal end along the longitudinal axis <NUM> and the anchor member <NUM> is towards the distal end along the longitudinal axis <NUM>. In other words, an element is proximal to another element if it is closer to a central aperture <NUM> (shown in <FIG>) of the glenosphere <NUM> than the other element, and an element is distal to another element if it closer to a distal tip <NUM> (shown in <FIG>) of the anchor member <NUM> than the other element. At some points below, reference may be made to the anatomical location. In use when the implant is delivered into a patient's scapula, the distal tip <NUM> of the anchor member <NUM> is more medial on the patient, whereas the articular surface of the glenosphere <NUM> is more lateral on the patient.

<FIG> and <FIG> show that the baseplate <NUM> is oriented substantially perpendicular to the longitudinal axis <NUM> of the glenoid implant <NUM>. The baseplate <NUM> is shown coupled to the anchor member <NUM> in <FIG> and <FIG> and apart from the anchor member <NUM> in <FIG>. Referring now to <FIG>, the baseplate <NUM> has a proximal end <NUM> and a distal end <NUM>. The proximal end <NUM> comprises a proximal surface <NUM> and the distal end <NUM> comprises a distal surface <NUM>. The proximal surface <NUM> can be substantially parallel to the distal surface <NUM>. The baseplate <NUM> can also include a bone engaging surface <NUM>. A thickness of the baseplate <NUM> defined between the proximal surface <NUM> and the bone engaging surface <NUM> may correspond to the amount that the baseplate <NUM> extends above a surface of the bone when implanted. The thickness can be in a range between about <NUM> and about <NUM>, e.g., between about <NUM> and about <NUM>, e.g., about <NUM>. Thicknesses of about <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> are also contemplated. As discussed further below, <FIG> illustrates a modified embodiment of a baseplate 108J where the surface <NUM> is lateralized relative to the patient's mid-plane. A lateralized baseplate is one in which when combined with an articular component, the articulating surface is shifted laterally relative to the medical plane of the patient compared to an anatomical position of the articular surface. In the context of a reverse shoulder, the shifting can move the center of rotation of the humerus laterally compared to the position of the center of rotation prior to intervention. In the context of an anatomic shoulder prosthesis, the lateralized baseplate may support an anatomic articular surface that is shifted laterally relative to the medial surface compared to the glenoid surface prior to intervention. The bone engaging surface <NUM> can be substantially parallel to the proximal surface <NUM> and/or the distal surface <NUM>. <FIG> illustrate modified embodiments in which the bone engaging surface varies, e.g., providing a partial or full wedge shape for reasons discussed below.

The baseplate <NUM> also has a lateral surface <NUM> that spans between the proximal surface <NUM> of the baseplate <NUM> and the bone engaging surface <NUM> of the baseplate <NUM>. The surface <NUM> is disposed lateral with regard to the center of the implant <NUM> and also is disposed lateral of the mid-plane of the patient when the implant <NUM> is applied to the patient. The lateral surface <NUM> can have a circular profile when viewed in a cross-section plane extending parallel to the proximal surface <NUM>. The diameter of the circular profile can be between about <NUM> and about <NUM>, e.g., between about <NUM> and about <NUM>, e.g. about <NUM>. In some embodiments, the lateral surface <NUM> of the baseplate <NUM> is configured to form a portion of a friction lock engagement, such as a Morse taper. In one embodiment, the lateral surface <NUM> of the baseplate <NUM> is tronconical. The term tronconical, as used herein, refers to a shape or surface that is or is similar to a truncated cone. In some embodiments, the lateral surface <NUM> is configured with a gradually increasing perimeter in a direction from proximal surface <NUM> toward the bone engaging surface <NUM>.

As illustrated in <FIG>, in some embodiments, the baseplate <NUM> can include a central protrusion <NUM> that projects distally from the bone engaging surface <NUM> to the distal end <NUM>. The central protrusion <NUM> has an outer surface <NUM> that extends from the bone engaging surface <NUM> to the distal surface <NUM>. Referring now to <FIG>, the central protrusion <NUM> can include a first aperture <NUM> which may be cylindrical. In some embodiments, the first aperture <NUM> may include a groove <NUM> along an inner wall of the first aperture. The baseplate <NUM> can have a second aperture <NUM> that, in some embodiments, extends from the first aperture <NUM> to the proximal end <NUM> of the baseplate <NUM>, such that a lumen <NUM> is formed through the baseplate <NUM>. The second aperture <NUM> can include an internally threaded surface <NUM> as shown. In some embodiments, the second aperture <NUM> is smaller in diameter than the first aperture <NUM>.

<FIG> shows that the baseplate <NUM> includes a plurality of holes, e.g., two holes <NUM>, <NUM> positioned laterally outward of the lumen <NUM>, that are configured to accept perimeter anchor members <NUM>. The holes <NUM>, <NUM> extend from the proximal end <NUM> of the baseplate <NUM> to the bone engaging surface <NUM> of the baseplate <NUM>. These holes <NUM>, <NUM> are also illustrated in <FIG>, which illustrates a perspective view of the proximal end <NUM> of the baseplate <NUM> of <FIG>. As illustrated, the baseplate <NUM> may have a circular shape, with a thickness between the proximal surface <NUM> and the bone engaging surface <NUM> that is less than a diameter of the proximal surface <NUM>. It will be appreciated that the baseplate <NUM> need not be circular, and may have other shapes as well.

Referring to <FIG> and <FIG>, the holes <NUM>, <NUM> can be defined in part by internal members <NUM> that are disposed within recesses <NUM> in baseplate <NUM>. In some embodiments, the internal member <NUM> is semi-spherical and the recess <NUM> is semi-spherical, in order to permit movement of, e.g., rotation and/or tilting of the internal member <NUM> with respect to the baseplate <NUM>. The internal member <NUM> allows a longitudinal axis extending centrally through the holes <NUM>, <NUM> (for example longitudinal axis <NUM> extending through hole <NUM> as shown in <FIG>) to be aimed to some extent toward a desired anatomical feature. The movement of the internal member <NUM> allows the positioning and/or aiming of perimeter anchor members <NUM> toward a desired location. The longitudinal axis <NUM> extending through the hole <NUM> can be substantially parallel to a longitudinal axis <NUM> extending through the second aperture <NUM> and/or lumen <NUM>, as shown by the orientation of the internal member <NUM> in part defining the hole <NUM> or angled with respect to the longitudinal axis <NUM> of the second aperture <NUM> and/or lumen <NUM>, not shown.

The number and position of the holes <NUM>, <NUM> depends on many factors including the anatomical structure of the patient, the diameter of the perimeter anchor members <NUM>, and size constraints dictated by dimensions of the baseplate <NUM>. Thus, there may be fewer or greater holes and perimeter anchors members than illustrated. In some embodiments, perimeter anchor members <NUM> are inserted through the baseplate <NUM> from the proximal end <NUM> thereof. As shown in <FIG>, the perimeter anchor member <NUM> can be inserted in the general direction of Arrow A.

<FIG> shows that the anchor member <NUM> is configured to be attached to the bone of a patient. The anchor member <NUM> is generally formed of a cylindrical longitudinal portion <NUM> and a proximal head <NUM>, both of which extend along a longitudinal axis <NUM> of the anchor member <NUM>. The anchor member <NUM> has an external lateral surface <NUM> which may include a self-tapping threaded surface. Other lateral surfaces of anchor members are discussed below in connection with <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. As used herein, a threaded surface is right-handed when the driving action is performed with clockwise rotation and left-handed when the driving action is performed with counterclockwise rotation. The threading of the external lateral surface <NUM> of the anchor member <NUM> may be right-handed or left-handed. In some embodiments, the longitudinal portion <NUM> of the anchor member <NUM> comprises a distally tapered distal tip <NUM>.

<FIG> shows that the proximal head <NUM> can have a cavity <NUM> disposed about the longitudinal axis <NUM>. The cavity <NUM> extends distally from the proximal end of the proximal head <NUM>. In some embodiments, the cavity <NUM> comprises one or more flat surfaces that are capable of mating with a driver configured to apply rotational force to drive the anchor member <NUM> into the bone. For example, the cavity <NUM> can have a hexagonal cross-section, centered on the longitudinal axis <NUM>, configured to mate with a hexagonal cross-section driver. The proximal head <NUM> can comprise a groove <NUM>. In some embodiments, the groove <NUM> is a circumferential groove around an external surface of the proximal head <NUM>. The proximal head <NUM> may include an inclined surface <NUM>, the function of which is discussed in greater detail below.

Referring to <FIG> and <FIG>, the anchor member <NUM> and the baseplate <NUM> are coupled in the first aperture <NUM>, which is sized to accept the proximal head <NUM> of the anchor member <NUM>. In some embodiments, the glenoid implant <NUM> comprises a member <NUM>, as shown in <FIG>, <FIG> and <FIG>, that is sized to fit partly within the groove <NUM> in the proximal head <NUM> and partly within the groove <NUM> in the baseplate <NUM>. The member <NUM> can comprise a c-clip, O-ring or similar protruding device that can span at least a portion of the groove <NUM> in the proximal head <NUM> and at least a portion of the groove <NUM> in the baseplate <NUM>. Alternatively member <NUM> may be comprised of elastically deformable barbs, fingers, or other projections having one end attached to and angled away from either head <NUM> or baseplate <NUM> such that the projections are deformed between head and baseplate when head is inserted into baseplate and such that the unattached end of the projections elastically expands into groove in head or baseplate. In this way, the anchor member <NUM> is held at a fixed position along the longitudinal axis <NUM> of the glenoid implant <NUM>, shown in <FIG>, relative to the baseplate <NUM>. Preferably the coupling provided by the member <NUM> does not prevent the relative rotation of the anchor member <NUM> and the baseplate <NUM>. In some embodiments, as shown in <FIG> and <FIG>, the member <NUM> is retained within the groove <NUM> of the baseplate <NUM> before the proximal head <NUM> of the anchor member <NUM> is inserted into the first aperture <NUM>.

<FIG> depicts the anchor member <NUM> separate from the baseplate <NUM>, e.g., before being coupled to the baseplate. The anchor member <NUM> can be inserted from the distal end <NUM> of the baseplate <NUM> into the first aperture <NUM>. During insertion, the inclined surface <NUM> of the proximal head <NUM> initially contacts the member <NUM>. Further insertion of the anchor member <NUM> displaces the member <NUM> away from the axis <NUM>, farther into the groove <NUM>. Such displacement allows the anchor member <NUM> to be inserted farther into the first aperture <NUM>. The anchor member <NUM> is inserted into the first aperture <NUM> until the member <NUM> engages the groove <NUM> in the proximal head <NUM>. The anchor member <NUM> is retained in the baseplate <NUM> by the spanning of the member <NUM> across the gap between the longitudinally adjacent grooves <NUM>, <NUM>, as shown in <FIG>.

In some embodiments, the member <NUM> is deformed by the proximal head <NUM> when the proximal head <NUM> is inserted into the first aperture <NUM>. For example, the inclined surface <NUM> can provide a progressively larger force on the member <NUM> as the proximal head <NUM> is urged from the distal end <NUM> of the baseplate <NUM> proximally into the first aperture <NUM> of the central protrusion <NUM>. The inclined surface <NUM> can have an angle of about <NUM> degrees or greater. In this context, the angle is measured relative to the flattened proximal end of the proximal head <NUM>. In one embodiment, the member <NUM> has a corresponding inclined surface <NUM> (see <FIG>) that faces distally. When the groove <NUM> in the proximal head <NUM> aligns with the groove <NUM> in the baseplate <NUM>, the member <NUM> returns to a relaxed state, e.g., is no longer deformed and the member <NUM> functions to couple the anchor member <NUM> to the baseplate <NUM>. More specifically, the member <NUM> couples the proximal head <NUM> to the first aperture <NUM>.

<FIG> illustrates a member 240A having mating ends. In particular, the clip member 240A has a first end <NUM>, a second end <NUM>, and an arcuate segment <NUM> therebetween. The inclined surface <NUM> is provided along a distal-facing side of the arcuate segment <NUM>. The first and second ends <NUM>, <NUM> are configured to mate or nest together when urged toward each other. For example, the first end <NUM> can have a reduced thickness on the distal facing side thereof and the second end <NUM> can have a reduced thickness on a proximal facing side thereof. The reductions in thickness of the first and second ends <NUM>, <NUM> can sum to the total thickness of the arcuate segment <NUM> or more in various embodiment. As a result, the ends <NUM>, <NUM> can move from a spaced apart configuration to an overlapping configuration with minimal to no deflection of the ends <NUM>, <NUM> in a proximal-distal direction being required. Alternatively, the reductions in thickness of the first and second ends <NUM>, <NUM> can sum to less than total thickness of the arcuate segment <NUM>. In such embodiments, upon causing the ends <NUM>, <NUM> to overlap, deflection of the ends along the proximal-distal direction will occur causing a widening of the clip 240A in the region of the ends <NUM>, <NUM> compared to in the arcuate segment <NUM>. <FIG> illustrates an enlarged configuration of the member 240A, e.g., a configuration in which an anchor member is being inserted and the clip member 240A is enlarged to permit advancement of a head of the anchor member through the clip member 240A and a corresponding baseplate. These structures are examples of various means for preventing axial translation of the baseplate <NUM> relative to the anchor member <NUM> while permitting rotation therebetween.

<FIG> shows that the glenosphere <NUM> defines a convex, articular surface <NUM>. The glenosphere <NUM> defines an interior surface <NUM> configured to receive the baseplate <NUM>. In particular, the interior surface <NUM> of the glenosphere <NUM> is configured to couple with the lateral surface <NUM> of the baseplate <NUM>. In some embodiments, the interior surface <NUM> of the glenosphere <NUM> is configured to frictionally engage the surface <NUM>, e.g., in a Morse taper. In some embodiments, the interior surface <NUM> of the glenosphere <NUM> is tronconical. The glenosphere <NUM> can include an internal threaded surface <NUM>. In some embodiments, the glenosphere <NUM> comprises a creep-resistant material, such as a suitable metal including any of stainless steel, cobalt-chrome alloy, or titanium which permits the interior surface <NUM> to deflect slightly in connection with forming a secure connection such as a Morse taper.

Referring to <FIG> and <FIG>, the locking structure <NUM> can include a locking screw <NUM>, a compression washer <NUM>, and a threaded member <NUM>, which may be a bushing. The locking screw <NUM> has a body that extends along the longitudinal axis <NUM> when the assembly <NUM> is assembled. The locking screw <NUM> can have an external threaded surface <NUM> and a proximal head <NUM>, as shown in <FIG>. A lateral surface <NUM> of the locking screw <NUM> located between the external threaded surface <NUM> and the proximal head <NUM> has a smooth surface, e.g., one that is not threaded. In some embodiments, a driver can be introduced into the proximal head <NUM> of the locking screw <NUM> in order to rotate the locking screw <NUM>. The compression washer <NUM> is generally annular in shape in one embodiment. The threaded member <NUM> includes one or more internal threads <NUM> configured to mate with the external threaded surface <NUM> of the locking screw <NUM>. The threaded member <NUM> can include a sidewall <NUM> that forms an internal cavity <NUM> configured to house the compression washer <NUM>. The sidewall <NUM> can have an external threaded surface <NUM> that is configured to mate with an internal threaded surface <NUM> of the glenosphere <NUM>. The glenoid implant <NUM> is configured to be assembled as shown in <FIG> and <FIG>.

<FIG> shows that during assembly of the locking structure <NUM>, the compression washer <NUM> can be inserted into the internal cavity <NUM> of the threaded member <NUM> and housed within the sidewall <NUM>. The locking screw <NUM> can be inserted through the compression washer <NUM> from the proximal end to the distal end thereof. A portion of the external threaded surface <NUM> of the locking screw <NUM> passes through the central aperture of the compression washer <NUM>. The locking screw <NUM> can be inserted into the threaded member <NUM> such that the external threaded surface <NUM> of the locking screw <NUM> mates with the internal thread(s) <NUM> of the threaded member <NUM>. The locking screw <NUM> can be further rotated until the compression washer <NUM> is loosely retained between the threaded member <NUM> and the proximal head <NUM> of the locking screw <NUM>. The smooth lateral surface <NUM> can be disposed within the internal threads <NUM> of the threaded member <NUM>, when the compression washer <NUM> is loosely retained.

The locking structure <NUM>, which can include the locking screw <NUM>, the compression washer <NUM>, and the threaded member <NUM>, can be coupled to the glenosphere <NUM>, as shown in <FIG>. In some embodiments, the locking structure <NUM> is coupled to the glenosphere <NUM> after the locking structure <NUM> has been assembled, as described above. The threads on external surface <NUM> of the sidewall <NUM> of the threaded member <NUM> can be rotated to engage the internal threaded surface <NUM> of the glenosphere <NUM>. This may involve rotation of the locking screw <NUM> toward the threaded member <NUM>, so that the proximal head <NUM> of the locking screw <NUM> fits within the glenosphere <NUM>. The glenosphere <NUM> can have a central aperture <NUM> that allows access to the proximal head <NUM> of the locking screw <NUM>. The central aperture <NUM> permits a driver or other tool to engage the locking screw <NUM>. As shown in <FIG>, the proximal head <NUM> of the locking screw <NUM> can have a cavity with one or more flats, e.g., a hexagonal cavity, configured to mate with the driver.

The locking structure <NUM> can be coupled to the baseplate <NUM>, as shown in <FIG>. In some embodiments, the locking structure <NUM> is coupled to the baseplate <NUM> after the locking structure <NUM> has been assembled, as described above. In some embodiments, the locking structure <NUM> is coupled to the baseplate <NUM> after the locking structure <NUM> is coupled to the glenosphere <NUM>, as described above. The locking screw <NUM> can be rotated until the external threaded surface <NUM> of the locking screw <NUM> engages the second aperture <NUM> in baseplate <NUM>, in particular the threaded surface <NUM> (See <FIG>). When the locking screw <NUM> is rotated, the locking screw <NUM> traverses the second aperture <NUM> distally toward the anchor member <NUM>. Further rotation of the locking screw <NUM> brings the distal tip <NUM> of the locking screw <NUM> into contact with the proximal head <NUM> of the anchor member <NUM>. In some embodiments, the distal tip <NUM> of the locking screw <NUM> enters the cavity <NUM>. The locking screw <NUM> is capable of applying a force to the proximal head <NUM> of the anchor member <NUM>. In some embodiments, this downward (e.g., distally directed) force applies a compression force to the member <NUM> such that the member <NUM> applies a frictional force to the groove <NUM> on the proximal head <NUM>. A friction force will also be applied by the distal tip <NUM> to the wall at the distal end of the cavity <NUM>. The distally directed forces created by the locking screw <NUM> on the anchor member <NUM> and/or the member <NUM> are sufficient to reduce or prohibit the rotation of the anchor member <NUM> with respect to the baseplate <NUM>. For example, high friction can arise due to the high normal force generated by action of the locking screw <NUM>.

Referring to <FIG>, when the locking screw <NUM> is rotated and advanced towards the anchor member <NUM>, the locking screw <NUM> can cause a force to be applied to the glenosphere <NUM>. Rotation of the locking screw <NUM> can move the proximal head <NUM> toward the distal end of the threaded member <NUM>. Rotation of the locking screw <NUM> can bring the proximal head <NUM> of the locking screw <NUM> into contact with the compression washer <NUM>. In some embodiments, the proximal head <NUM> of the locking screw <NUM> can apply a downward force on the compression washer <NUM>. The compression washer <NUM> can thereby apply a downward force on the threaded member <NUM>. The threaded member <NUM> including the sidewall <NUM> can be coupled with the internal threaded surface <NUM> of the glenosphere <NUM>. The threaded member <NUM> can provide a downward force on the glenosphere <NUM>, as the locking screw <NUM> is advanced distally toward the anchor member <NUM>. This causes the glenosphere <NUM> to move distally and engage the lateral surface <NUM> of the baseplate <NUM>.

<FIG> shows that the lateral surface <NUM> of the baseplate <NUM> is tapered, e.g., tronconical, in some embodiments. The glenosphere <NUM> defines an interior surface <NUM> that is tapered or tronconical or otherwise configured to create high friction with the baseplate <NUM>. The surfaces <NUM>, <NUM> can be initially engaged in any suitable manner, e.g., using an impactor to create an initial frictional engagement therebetween. In some embodiments, the lateral surface <NUM> of the baseplate <NUM> and the interior surface <NUM> of the glenosphere <NUM> form a Morse taper. The distally directed force of the locking screw <NUM> enhances, e.g., makes more rigid, the connection between the anchor <NUM> and baseplate <NUM>, reducing or eliminating play between these components. As a secondary advantageous effect, the distally directed force of the locking screw <NUM> can also increase the friction at the surfaces <NUM>, <NUM>. The frictional force created by the coupling of the glenosphere <NUM> and the baseplate <NUM> add to the rigidity of the glenoid implant <NUM>.

The compression washer <NUM> shown in <FIG> can have multiple functions. The compression washer <NUM> is configured to fill the space between the proximal head <NUM> of the locking screw <NUM> and the threaded member <NUM> to add to the rigidity of the implant <NUM>. In particular, rotation of the locking screw <NUM> applies a force on the compression washer <NUM> which can compress or otherwise deform the compression washer <NUM>. In the compressed state, the compression washer <NUM> applies a force to maintain the position of the locking screw <NUM>. The placement and use of the compression washer <NUM> facilitates the rigidity of the glenoid implant <NUM> by filling the space between the proximal head <NUM> of the locking screw <NUM> and the threaded member <NUM>. Additionally, the locking screw <NUM> applies a force to the anchor member <NUM>. This force enhances the connection of the anchor member <NUM> to the baseplate <NUM> which reduces or eliminate play between these components to minimize or reduce loosening of these components over time. For example, maintaining the position of the locking screw <NUM>, the compression washer <NUM> further minimizes or prevents rotation, translation, or micromotion of the anchor member <NUM> with respect to the baseplate <NUM>. In some embodiments, the compression washer <NUM> tends to distribute the force of the proximal head <NUM> of the locking screw <NUM>. The compression washer <NUM> causes the proximal head <NUM> of the locking screw <NUM> to be in contact with a larger surface area of the threaded member <NUM>. The distribution of force facilitates the downward movement of the glenosphere <NUM> with respect to the baseplate <NUM> and/or enhances friction between the surfaces <NUM>, <NUM> as discussed above. The compression washer <NUM> further minimizes or prevents rotation, translation, or micromotion of the glenosphere <NUM> with respect to the baseplate <NUM>.

The glenoid implant <NUM> can have a modular design, meaning that the anchor member <NUM> and the baseplate <NUM> can be interchangeable with another anchor member and/or another baseplate. In some embodiments a single baseplate can couple with any one of a plurality of anchor members in a kit including a plurality of anchor members, such as shown in <FIG>. In some embodiments, a single anchor member can couple with any one of a plurality of baseplates in some or in another kit, including for example the baseplates shown in <FIG>. The proximal heads of the anchor members can have a consistent diameter among a plurality of anchor members in some kits. Further, the grooves and the cavities of the anchor members can be consistent in size and location among a plurality of anchor members in some kits. In some embodiments, the grooves and first apertures of the baseplates is a consistent diameter among a plurality of baseplates in the kit. Further, the second apertures and the lumens of the baseplates can be consistent in size and location among a plurality of baseplates. This allows for the interchangeability of the plurality of anchor members with any one of a plurality of baseplates or the plurality of baseplates with any one of a plurality of anchor members.

<FIG> show that the modular design allows the use of a plurality of anchor members with a given baseplate. In <FIG>, the anchor members 104A-104E include a longitudinal portion 216A, 216B, 216C, 216D or 216E, a distal end, a proximal head <NUM>, and a groove <NUM>. The anchor members 104A-104E shown in <FIG> are compatible with the baseplates <NUM>, described herein. The anchor members 104A-104E may include additional features of anchor members described herein.

<FIG> differ with respect to the external lateral surface and the longitudinal portion of the anchor member. The anchor members 104A, 104B, 104C may have a longitudinal portion 216A, 216B, 216C having different configurations, e.g., diameters and/or lengths. The longitudinal portion 216A of anchor member 104A has a constant diameter and thread pitch, but different lengths in different embodiments. The anchor member 104B has a different diameter and/or thread pitch from the anchor member 104A. The anchor member 104C has a different diameter and/or thread pitch from the anchor members 104A and 104B.

As shown in <FIG>, the anchor members 104A-104C can have a different diameter in the longitudinal portions 216A-216C. In some embodiments, the diameters are in the range of <NUM> to <NUM>. Larger diameter anchor members can be useful for revision of total shoulder arthroplasty or failed reverse shoulder arthroplasty. The anchor members of the plurality of anchor members can have different lengths, and in some embodiments the lengths of the anchor member can be in the range of <NUM> to <NUM>. The external lateral surface is configured to engage a bony surface. The configurations shown in <FIG> demonstrate the ability to provide, e.g., in a kit, a plurality of anchor members from which a particular anchor member can be selected based on the anatomy of a patient.

<FIG> depicts another embodiment of an anchor member 104D. The anchor member 104D has a cylindrical section of material along the longitudinal portion 216D of the anchor member 104D. The cylindrical section includes porous material <NUM> to promote bony ingrowth. That is, bone material can grow into the pores of the cylindrical section of porous material <NUM>. The longitudinal portion 216D may include an external threaded surface to engage bone. <FIG> show the proximal head <NUM> of the anchor members 104A-104D may have a consistent configuration. For example, the proximal head can have a unitary diameter among a plurality of anchor members. The anchor member may include a groove that engages member <NUM> as described above.

<FIG> shows an anchor member 104E. The longitudinal portion 216E can include an external lateral surface that is generally without threads to be tapped or otherwise pressed into the bone. The external lateral surface may be comprised of ridges, circumferential ridges, rough coatings, knurling, plasma sprayed metal, or other rough surfaces that will increase the friction of the longitudinal portion 216E relative to the bone thereby helping to prevent longitudinal portion 216E from pulling out of the bone. The anchor member 104E comprises a proximal head <NUM> that is the same as the proximal heads in the anchor members of <FIG>. The longitudinal portion 216E can be tapered, e.g., having a narrower transverse profile adjacent to its distal end and a wider transverse profile adjacent to the head <NUM>. The proximal head <NUM> has a groove <NUM> that couples with the baseplate <NUM> in the same manner as the other anchor members discussed herein. The anchor member 104E provides additional options for the interchangeable anchor member.

The anchor members <NUM>, 104A-104E (described above) and <NUM> (described below in connection with <FIG>) can be made from a biocompatible material such as a metal alloy, polymer, or ceramic. For example, anchor members can be made from stainless steel, titanium, titanium alloy, cobalt-chrome alloy, and/or PEEK. In some embodiments, the anchor member <NUM>, 104A-104E, <NUM> is more rigid than the baseplate <NUM>. The rigidity of the anchor member <NUM>, 104A-104E, <NUM> prevents deformation of the anchor member during insertion into the bone and during use as a glenoid implant.

<FIG> illustrate embodiments of baseplates having features similar to those described above and/or additional features. One or more of these features may be interchanged or incorporated into any of the baseplates described herein. In the embodiment of <FIG>, G and H, on the proximal surface <NUM>, the baseplate <NUM>, <NUM>, <NUM> is illustrated with tool engaging grooves or openings <NUM>. The tool engaging grooves <NUM> are configured to engage two radially extending legs of a tool described below with reference to <FIG>. The grooves <NUM> can be present on any of the embodiments of the baseplate described herein.

As shown in the embodiments of <FIG>, <FIG> and <FIG>, the central protrusion <NUM> is centrally disposed relative to the lateral surface <NUM> of the baseplate <NUM>. For example, a central longitudinal axis of the central protrusion <NUM> can be disposed equidistant from points along the lateral surface <NUM>, as shown in <FIG>. <FIG> illustrate more features of baseplates that can be combined with and/or substituted for features illustrated in the embodiment of <FIG> and <FIG>. For example, <FIG> illustrate baseplates 108B-108D with configurations that can augment or compensate for scapula bone loss. <FIG> shows that the baseplate 108B has a proximal surface 144B. <FIG> shows that the bone engaging surface <NUM> has a curved surface (e.g., a convex surface). The bone engaging surface <NUM> is symmetrical with respect to the central protrusion. <FIG> shows that the bone engaging surface <NUM> of the baseplate 108C has an anatomically curved surface. The curved surface can be nonsymmetrical with respect to the central protrusion. The curved surface can be selected by the surgeon to match an anatomic feature of the patient's bone. The bone engaging surfaces <NUM>, <NUM>, <NUM> can match the curvature of the glenoid cavity of the patient.

<FIG> illustrate further baseplates 108J-<NUM> that can compensate for bone loss, thereby augmenting the bone at the joint. The baseplate 108J has a proximal portion 136J and a distal portion 140J. The proximal portion 136J can incorporate any of the features or components of the proximal end <NUM> of the baseplate <NUM> of <FIG>, <FIG>, and <FIG> or of proximal ends of other baseplates herein. The distal portion 140J is formed by a process of additive manufacturing, which is discussed below. The additive manufacturing process creates a porous titanium structure on the distal surface of the baseplate. In particular, the distal surface 148J and central protrusion 160J comprise the porous titanium structure described herein. The distal surface 148J can be a surface that extends radially outward from the central protrusion 160J and engages an exposed face of the glenoid. The central protrusion 160J can be configured to be advanced into the bone distal of the bone surface contacted by the distal surface 148J. The porous titanium structure can be disposed throughout the distal portion 140J, which contact the scapula at the glenoid surface. Any technique can be used to form the entirely of the distal portions of the baseplates herein, including additive manufacturing. Additive manufacturing can be used to provide a porous titanium structure in the entirety of the distal portions of the baseplates, including the central protrusions. This approach can provide a monolithic portion, e.g., where the same porous structure extends through the entire thickness of the monolithic portion of the baseplate.

The baseplate 108J also includes an augment portion 150J. The augment portion 150J is configured to move a proximal surface 144J of the baseplate 108J to a selected location and/or to replace or in-fill areas of bone loss with or without a lateral shifting of the center of rotation of the humerus at the shoulder joint. For example, the baseplate 108J may be applied to the patient by attaching it to the glenoid region of the scapula. In certain patients, wear of the glenoid may be substantially uniform. Uniform wear causes the pre-implantation glenoid surface to be shifted medially compared to an un-worn and/or un-diseased position of the glenoid surface. In such patients, the augment portion 150J shifts the location of baseplate 108J and thereby the articulating surface of a glenosphere coupled with the baseplate <NUM>. The baseplate 108J shifts the position of the glenosphere laterally. The position of the surface 144J of the lateralized baseplate 108J would be more lateral compared to the position of the same surface of the baseplate <NUM> that would result if the baseplate <NUM> were used. That is the surface 144J would be farther from the medial plane of the body than would be the surface <NUM> on the same patient with the same glenoid condition.

<FIG> shows a baseplate <NUM> that is similar to the baseplate 108J except as described differently below. The baseplate <NUM> has an augment portion <NUM> that is non-uniform in thickness. The augment portion <NUM> can be formed in any suitable way, for example by additive manufacturing producing a porous metal structure. The augment portion <NUM> presents a first thickness, t1, along one peripheral side of the baseplate <NUM> and a second thickness, t2, along a second peripheral side of the baseplate. The second thickness is larger than the first thickness. The second thickness can be provided by progressively thickening the augment portion <NUM> in a lateral direction (e.g., toward the left in <FIG>). In the illustrated embodiment, the thickness of the augment portion <NUM> linearly increases across the width of the baseplate <NUM>. In the illustrated embodiment, a distal surface <NUM> is provided that engages the surface of the scapula, e.g., at the glenoid. The surface <NUM> has a first peripheral portion <NUM> that is parallel to a proximal surface <NUM> of the baseplate <NUM>. The surface <NUM> has a second peripheral portion <NUM> that is disposed at an angle relative to the proximal surface <NUM>. The angle between the second peripheral portion <NUM> and the proximal surface <NUM> can be selected based on the amount of bone to be replaced or supplemented by the augment portion <NUM>. The first peripheral portion <NUM> of the surface <NUM> can be located closer to the proximal surface <NUM> than is the second peripheral portion <NUM> of the surface <NUM>. The augment portion <NUM> provides a partial wedge, e.g., a half-wedge configuration. The augment portion <NUM> is for augmenting bone degeneration and/or disease in the location beneath a glenoid implant including the baseplate <NUM>. Although the embodiment of <FIG> could be used where uneven wear or disease is provided, the baseplate <NUM> can be advantageously used in a bone preserving manner such that the un- or less worn portions which would be disposed beneath the first peripheral portion and the less-thick region of the second peripheral portion need not be reamed or otherwise removed to accommodate the baseplate <NUM>. In various embodiments, the entire distal portion of the baseplate <NUM> can be made of a porous structure, e.g., of a porous titanium structure, as discussed herein. The porous titanium structure can be formed by additive manufacturing. The augment portion <NUM> can be made of a porous structure, e.g., of titanium formed by additive manufacturing.

<FIG> shows a baseplate <NUM> that is similar to the baseplate <NUM> except as described differently below. In the baseplate <NUM> an augment portion <NUM> is provided that augments bone loss across the entire glenoid surface. In the half-wedge embodiment of <FIG>, the angled portion <NUM> starts or ends inward of the outer periphery of the baseplate <NUM>. For example, the angled portion <NUM> can start adjacent to or at the central protrusion <NUM>. In the full wedge configuration of the baseplate <NUM> of <FIG>, the angled portion <NUM> starts or ends at or adjacent to a peripheral portion of the baseplate <NUM> and starts or ends at the second peripheral portion, augment extends the full length of the implant The baseplate <NUM> has an augment portion <NUM> that is non-uniform in thickness. The augment portion <NUM> can be formed in any suitable way, for example by additive manufacturing producing a porous titanium structure. The augment portion <NUM> presents a first thickness, T1, along one peripheral side of the baseplate <NUM> and a second thickness, T2, along a second peripheral side of the baseplate. The second thickness T2 progressively, e.g., linearly, decreases compared to the first thickness T1 in one embodiment across the width of the baseplate <NUM>. In the illustrated embodiment, a distal surface <NUM> is provided that engages the surface of the scapula, e.g., at the glenoid. The surface <NUM> has a first peripheral portion <NUM> that is parallel to a proximal surface <NUM> of the baseplate <NUM>. The surface <NUM> has a second peripheral portion <NUM> that is disposed at an angle relative to the proximal surface <NUM>. The angle between the second portion and the proximal surface <NUM> can be selected based on the amount of bone to be replaced or supplemented by the augment portion <NUM>. The first peripheral portion of the surface <NUM> can be located farther from the proximal surface <NUM> than is the second peripheral portion of the surface <NUM>. The augment portion <NUM> provides a full-wedge configuration. The augment portion <NUM> is for augmenting bone degeneration or disease in the location beneath a glenoid implant including the baseplate <NUM>. Although the embodiment of <FIG> could be used where uneven wear or disease is provided, the baseplate <NUM> can be advantageously used in a bone preserving manner such that the un- or less worn portions which would be disposed beneath the less-thick region of the second peripheral portion need not be reamed or otherwise removed to accommodate the baseplate <NUM>.

Among the advantages provided by using additive manufacturing to form an augment portion, such as the augment portion 150J, the augment portion <NUM> or the augment portion <NUM> is that the augment portion can be made patient specific in a fast and cost effective manner. For an individual patient, the need to replace or in-fill bone loss can be determined, such as by pre-operative imaging. The augment portion can be formed in accordance with this determination. In other words, the augment portion can be made to replace the lost bone, as determined pre-operatively, when fully integrated into the joint space, e.g., into the scapula or glenoid. This way the fit of the joint can be more accurate for an individual patient, which can lead to better outcomes such as by reducing the chance of post-operative patient discomfort and joint dislocation.

<FIG> illustrate that the protrusion <NUM> can be eccentric with respect to the baseplate 108D. In each of these embodiments, the protrusion <NUM> is not centrally disposed relative to the lateral surface <NUM> of the baseplate 108D. An anchor member such as anchor member <NUM> can be inserted into the protrusion <NUM>, as discussed above with reference to central protrusion <NUM>. When an anchor member is coupled to the baseplate 108D, the anchor member is eccentric with respect to the baseplate 108D.

<FIG> each illustrate embodiments of a baseplate 108F, <NUM>, <NUM> with a plurality of holes, e.g., five, holes <NUM> or four holes <NUM>. The holes are located around the periphery of the lumen <NUM>. In some embodiments, the holes are equidistant with respect to each other, in other words, the holes are equally spaced around the lumen <NUM>. <FIG> further illustrates that tool engaging grooves <NUM> may also be provided between holes <NUM>.

<FIG> illustrates a baseplate <NUM> that has further features that can be combined with any of the other baseplates herein. The baseplate <NUM> has a radial protrusion <NUM> disposed between the proximal surface <NUM> and the bone engaging surface (not shown but opposite the surface <NUM>). The radial protrusion <NUM> has a proximally oriented face <NUM>. The face <NUM> can include an annular surface extending outward from a distal portion of the peripheral surface <NUM>. In one embodiment, the face <NUM> abuts the glenosphere <NUM> when the glenoid implant <NUM> is fully assembled. The radial protrusion <NUM> can also define a positive stop for the distal advancement of the glenosphere <NUM> during assembly of the glenoid implant <NUM> such that the glenosphere is not overstressed by being advanced too far over the surface <NUM>.

In embodiments, such as those illustrated in <FIG>, the baseplates are at least partially formed by additive manufacturing. In certain additive manufacturing techniques a material is applied to create a three dimensional porous metal structure. <FIG> shows a baseplate 108I that has a proximal end 136I and a distal end 140I. The proximal end 136I can incorporate any of the features or components of the proximal end <NUM> of the baseplate <NUM> or of proximal ends of other baseplates herein. The distal end 140I is formed by a process of additive manufacturing. More specifically, the portion of the baseplate that interacts with the bone may comprise a porous metal such as porous titanium (Ti-6Al-4V). As a result, the distal portions (e.g., the protrusion 146I and corresponding protrusions in other embodiments and/or the augment portion 150J-L) comprise a monolithic porous titanium structure, which contacts the scapula at the glenoid surface. Porous titanium has a modulus similar to bone or of about <NUM> GPa. Matching the modulus of the porous titanium to the bone may enable better stress transfer from the implant to the bone, reducing wear on the bone, and increasing strength at the bone/implant interface.

The porous titanium structure includes a pore size of from about <NUM> to about <NUM>, in embodiments from about <NUM> to about <NUM> in further embodiments from about <NUM> to about <NUM>. The porosity of the porous titanium structure may be optimized per implant geometry and anatomy and can be of about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, and <NUM>%.

Porous titanium can be formed by an additive manufacturing process, including a <NUM> dimensionally (<NUM>-D) printing process where layers of titanium are formed to create a three dimensional structure. The initial layer or layers are formed by such a method directly onto a portion or surface of the baseplate. The <NUM>-D printing process includes direct metal laser sintering onto the implant, more specifically, the baseplate. First, blanks are formed by sintering titanium powder with a laser directly onto the substrate or baseplate. Next, the blanks can be machined, constructed or shaped to create a specific geometry of the bone-engaging surface. In another technique, a machined blank is initially provided. Then, a first layer of a powder form of the material desired to make up the formed portion is disposed on and fused to the surface of the blank. After this, a second layer of the powder is applied to the part and is fused to the first layer and/or to the blank. This process is repeated to progressively build up the part. Any of the layers can be full or partial layers to impart complex geometries. After a plurality of layers is fused to the blank and to the other layers to form the desired geometry, including an irregular geometry if called for, the part can be further processed to eliminate any unfused powder. This process can produce a porous implant well adapted for being integrated into bone by bony ingrowth. In embodiments, the blanks are shaped to create either a lateralized (as in <FIG>), half-wedge (as in <FIG>) or full-wedge (as in <FIG>) augmented baseplate. Although the <NUM>-D process is used herein to create augmented baseplates, other portions and surfaces of the implants may comprise porous titanium, and are within the scope of this disclosure, including, but not limited to central anchors or screws or portions thereof, peripheral anchors or screws or portions thereof and central posts. Once constructed, the porous structure and the solid substrate of baseplate comprise a monolithic, or one-piece, structure. Alternatively, Electron Beam Melting (EBM) can be used to <NUM>-D print a porous structure on the implant.

<FIG> illustrate a glenoid implant according to the invention, comprising an anchor member <NUM> and a baseplate <NUM>. The proximal head <NUM> of the anchor member <NUM> includes a threaded surface <NUM>, as shown in <FIG>. The threads disposed on the surface <NUM> of the proximal head <NUM> of the anchor member <NUM> may be left-handed. The first aperture <NUM> in the baseplate <NUM> includes a threaded surface <NUM> configured to mate with the threads on the surface <NUM> of the proximal head <NUM>. The threaded surface <NUM> of the first aperture <NUM> can be left-handed. Further, the baseplate <NUM> comprises a space in the form of a central portion <NUM> that is not threaded. The central portion <NUM> can be surrounded by a smooth surface. The threaded surface in the aperture <NUM> is disposed between the smooth surface and a distal surface <NUM> of the baseplate <NUM>. The smooth surface of the first aperture <NUM> has a length (e.g., along the longitudinal axis of the aperture, left to right on <FIG>) and a width (e.g., a diameter or dimension transverse to the longitudinal axis of the aperture, up and down on <FIG>). The threaded surface <NUM> has a length less than or equal to the length of the smooth surface disposed around the central portion <NUM> of the first aperture. When the threaded surface <NUM> is housed in the central portion <NUM>, rotation in one direction does not cause the threaded surface <NUM> and the threads in the aperture <NUM> to engage each other in a manner permitting advancement along the longitudinal axis of the anchor member <NUM> or the baseplate <NUM>. For example, if the threaded surface <NUM> and the threads in the aperture <NUM> are left-handed, the baseplate <NUM> can be rotated clockwise without the threads engaging and without the baseplate advancing axially along the longitudinal axis of the anchor member <NUM>. Thus, the anchor member <NUM> and the baseplate <NUM> are restrained in axial translation but are permitted to rotate relative to each other. Of course, the threaded surface <NUM> and the threads in the aperture <NUM> could be right-handed and in such arrangement the baseplate could be rotated counterclockwise without the threads engaging.

In some embodiments, the anchor member <NUM> can be advanced from the distal end <NUM> of the baseplate <NUM>, through the first aperture <NUM>. The threaded surface <NUM> of the anchor member <NUM> can engage the threaded surface <NUM> of the baseplate <NUM>. The anchor member <NUM> can be advanced until the threaded surface <NUM> on the proximal head <NUM> is proximal of the threaded surface <NUM> such that the threads of the surface <NUM> disengage from the threads of the threaded surface <NUM> of the first aperture <NUM>. When the threaded surface <NUM> of the proximal head <NUM> disengages from the threaded surface <NUM> of the first aperture <NUM>, the threaded surface <NUM> of the proximal head <NUM> is disposed within the central portion <NUM>. <FIG> show that in this configuration, the anchor member <NUM> is prevented from axial translation with respect to the baseplate <NUM> but is freely rotatable with respect to the baseplate <NUM>.

In some embodiments, the proximal head <NUM> of the anchor member <NUM> is advanced into the central portion <NUM> of the baseplate <NUM> before the anchor member <NUM> is driven into the bone. For instance, the manufacturer can provide the anchor member <NUM> coupled to the baseplate <NUM>, as shown in <FIG>, or this assembly can be provided by the surgeon after selecting the baseplate <NUM> and/or the anchor member <NUM> from a plurality of baseplates and/or anchor members as discussed elsewhere herein. The baseplate <NUM> can be held in a desired orientation when the anchor member <NUM> is driven into the bone. In some embodiments, the baseplate <NUM> is maintained in a desired orientation by one or more tools, such as the cannulated tools as described in connection with <FIG> below while the anchor member <NUM> is advanced by rotation into the bone.

According to some methods, the anchor member <NUM> is partially or fully seated within the bone before the proximal head <NUM> of the anchor member <NUM> is advanced into the central portion <NUM> of the baseplate <NUM>. As noted above, the first aperture <NUM> and the threaded surface <NUM> of the proximal head <NUM> can have left-handed threads. The external lateral surface <NUM> of the anchor member <NUM> can have right-handed threads. The baseplate <NUM> can be rotated with respect to the proximal head <NUM> such that the proximal head <NUM> advances through the first aperture <NUM> and is disposed within the central aperture <NUM> without disengaging the external lateral surface <NUM> of the anchor member <NUM> from the bone. Once the threaded surface <NUM> on the proximal head <NUM> is contained within the central portion <NUM>, the surgeon can then rotate the baseplate <NUM> to align the baseplate <NUM> with anatomical features of the patient. In some embodiments, following proper orientation of the baseplate <NUM> relative to the patient, the surgeon can fully seat anchor member <NUM> into the bone. In some embodiments, the locking structure <NUM>, described in greater detail above, can be utilized with anchor member <NUM> and baseplate <NUM>. The locking structure <NUM> applies a force to the anchor member <NUM>, which prevents subsequent rotation of the anchor member <NUM> with respect to the baseplate <NUM>. The locking structure <NUM> may also apply a force to glenosphere <NUM>, which creates a frictional lock with the baseplate <NUM>. Further details regarding the use of the locking structure and methods of using the anchor member <NUM> and baseplate <NUM> are described below.

<FIG> shows that the anchor member <NUM> can be cannulated. The cannulation allows the anchor member <NUM> to slide over a guide wire during insertion. The use of a guide wire helps to ensure the proper placement of the anchor member <NUM> within the bone. The anchor members <NUM>, 104A-104E can also be cannulated to facilitate placement.

<FIG> show an embodiment of a glenoid implant <NUM> that is similar to the embodiments of <FIG> and <FIG> except as described differently below. Descriptions of features of the embodiments of <FIG> and <FIG> may be combined singly or in combination with the features of <FIG>. The implant <NUM> is configured to be implanted in a glenoid of a scapula to provide a portion of a shoulder prosthesis. In certain configurations, the implant <NUM> provides a reverse shoulder component including the glenosphere <NUM>. The glenosphere <NUM> provides an articulating surface as discussed above.

<FIG> shows that the implant <NUM> includes an anchor member <NUM>. The anchor member <NUM> is shown in <FIG> and <FIG> and has a longitudinal portion <NUM> and a proximal head <NUM>. The proximal head <NUM> has an external threaded surface <NUM>. The longitudinal portion <NUM> and the anchor member <NUM> are configured to be secured to a bone, e.g., into the scapula at the glenoid. In some embodiments, anchor member <NUM> can be a bone screw component of the implant <NUM>.

<FIG> shows that in the anchor member <NUM> (lower right hand member of the kit <NUM>), the proximal head <NUM> can include a first smooth portion <NUM> disposed distally of the external threaded surface <NUM> and a second smooth portion <NUM> disposed proximally of the external threaded surface <NUM>. When assembled, the proximal smooth portion <NUM> can extend between the physical proximal end (articulating surface) of anchor member <NUM> and the proximal end of the external threaded surface <NUM>. In some cases, the proximal smooth portion <NUM> can extend entirely from the proximal end of the anchor member <NUM> to the external threaded surface <NUM>. The distal smooth portion <NUM> can extend between the external threaded surface <NUM> and threads disposed on the longitudinal portion <NUM>. The distal smooth portion <NUM> can extend entirely from the external threaded surface <NUM> to the threads disposed on the longitudinal portion <NUM>. The proximal smooth portion <NUM> provides an axial insertion zone that is useful in aligning the threads of the external threaded surface <NUM> with corresponding mating threads of the implant <NUM> as discussed further below. The distal smooth portion <NUM> is adapted to be aligned with, e.g., at the same longitudinal position as, threads of a baseplate <NUM> of the implant <NUM> in a configuration that permits axial restraint of the anchor member <NUM> while permitting rotational orientation of the baseplate <NUM> as discussed further below.

The baseplate <NUM> that can be similar to any of the baseplates described herein. <FIG> shows an example of the baseplate <NUM> in more detail. The baseplate <NUM> includes a proximal end <NUM> and a distal end <NUM>. A protrusion <NUM> can be disposed on the distal side of the baseplate <NUM>. The protrusion <NUM> can be a central protrusion or can be located peripherally as described herein in connection with certain embodiments. The distal end <NUM> includes a first aperture <NUM> sized to accept the proximal head <NUM> of the anchor member <NUM>. The first aperture <NUM> comprises an internal threaded surface <NUM> and a space in the form of a central portion with a smooth surface <NUM> disposed therein. The smooth surface can be located proximal of the internal threaded surface <NUM>.

The smooth surface <NUM> is disposed in the central protrusion <NUM> at a location immediately adjacent to the threaded surface <NUM> in one embodiment. The smooth surface <NUM> defines a portion that permits rotational orienting of the baseplate <NUM> relative to the anchor member <NUM> without axially advancing the baseplate <NUM> relative to an anchor member. The smooth surface <NUM> can define a length of the first aperture <NUM> that has a larger diameter than that of the threaded surface <NUM>. The larger diameter section can correspond to a reduced wall thickness radially outward of the smooth surface <NUM> in the central protrusion <NUM>. In other embodiments, the central protrusion <NUM> could be thicker in the area of the smooth surface <NUM> to allow the wall thickness to not decrease in the area of the smooth surface <NUM>. The length of the smooth surface <NUM> preferably is larger than the length of the external threaded surface <NUM> of the proximal head <NUM> of the anchor member <NUM>. As a result, the external threaded surface <NUM> can be aligned with, e.g., disposed within the smooth surface <NUM> in one configuration.

The central protrusion <NUM> preferably also has an anchor member interface zone <NUM> proximal of the smooth surface <NUM>. The interface zone <NUM> surrounds the proximal smooth portion <NUM> of the anchor member <NUM> in one configuration. The proximal smooth portion <NUM> can be used to initially align the anchor member <NUM> with the baseplate <NUM>. For example, the proximal smooth portion <NUM> can include an unthreaded length that can have an outer diameter that is less than the inner diameter of the threads of the internal threaded surface <NUM> of the baseplate <NUM>. This permits the unthreaded length of the proximal smooth portion <NUM> to be inserted into the first aperture <NUM> and through the internal threaded surface <NUM> without any threaded engagement. The unthreaded engagement allows the surgeon to align the longitudinal axis of the anchor member <NUM> with the longitudinal axis of the aperture <NUM> or otherwise position the anchor member relative to the baseplate <NUM> to allow for quick threading of the member <NUM> to the baseplate <NUM>. Such alignment facilitates engaging thread-start(s) of the internal threaded surface <NUM> with the thread start(s) on the external threaded surface <NUM> of the anchor member <NUM> without crossthreading these components. In this context, a thread-"start" is a broad term that includes either end of a thread regardless of whether the end is initially threaded into another structure.

In use, the arrangement of the implant <NUM> provides for axially restraining the position of the baseplate <NUM> relative to the anchor member <NUM>. At the same time, the implant <NUM> permits rotational positioning of the baseplate <NUM> relative to the anchor member <NUM>. For example, when the external threaded surface <NUM> of the proximal head <NUM> is disposed proximal of the internal threaded surface <NUM> of the first aperture <NUM>, the threads disposed on these threaded surfaces are disengaged. In the illustrated arrangement, the external threaded surface <NUM> is disposed adjacent to, e.g., in the same longitudinal position within the aperture <NUM> as the smooth surface <NUM> of the first aperture <NUM>. In this position, the baseplate <NUM> is axially restrained but is configured to allow rotational alignment. In this context, the threads are said to be in the same longitudinal position along the longitudinal axis of the aperture <NUM> when the distal-most aspect of the external threaded surface <NUM> the anchor member <NUM> is located proximal of a distal end of the smooth surface <NUM> of the first aperture <NUM>. In some embodiments, the proximal-most aspect of the external threaded surface <NUM> of the anchor member <NUM> is located distal of the proximal end of the smooth surface <NUM> when the threaded surface <NUM> is in the same longitudinal position as the surface <NUM>. In some configurations, the distal-most aspect of the external threaded surface <NUM> is proximal of the distal end of the smooth surface <NUM> and the proximal-most aspect of the external threaded surface <NUM> is distal of the proximal end of the smooth surface <NUM>. When the external threaded surface <NUM> is in the same longitudinal position as the smooth surface <NUM> there is no thread engagement and thus the threads do not result in axially advancement of the baseplate <NUM> relative to the anchor member <NUM> upon relative rotation.

The baseplate <NUM> also includes an internal member <NUM> disposed therein. The internal member <NUM> is disposed peripherally relative to the first aperture <NUM>. The internal member <NUM> is moveably mounted in the baseplate <NUM>. For example, the internal member <NUM> can have a spherical outer surface <NUM> that is mated with a spherical inner surface <NUM> disposed in the baseplate <NUM>. As discussed below, the internal member <NUM> can have various flats or projections as well as an outer surface that otherwise generally conforms to a sphere in at least one embodiment. In other embodiments, the internal member <NUM> has a curved surface that is moveable within the baseplate <NUM> about a range of motion enabling directing peripheral screws (e.g., the peripheral screw <NUM> discussed above in connection with <FIG>) into the bone. The internal member <NUM> can have internal threads <NUM> that mate with the peripheral screw. <FIG>, which are discussed below, elaborate on the peripheral screws and internal member <NUM> provide advantageous features discussed below.

<FIG> also shows a kit <NUM> that can include the anchor member <NUM> as well as anchor members 404A and 404B having different length and diameter respectively. The anchor member 404A may be well suited for patients with thinner bone portions beneath the glenoid. The anchor member 404B may be well suited for a revision patient, e.g., a patient being adapted from an anatomical shoulder joint to a reverse shoulder joint, where a pre-existing hole in the scapula can be re-used with a larger diameter screw. In each case, the proximal portion of the anchor member 404A, 404B is adapted for the same engagement with a baseplate as described above. That is the smooth sections <NUM>, <NUM>, where provided, can be received in the baseplate <NUM> and the threaded portion <NUM> can be disposed in the same longitudinal position in the aperture <NUM> as the space in the form of the central portion with the smooth surface <NUM> to permit rotation of the baseplate relative to the anchors 404A, 404B which rotation does not cause axial advancement of the baseplate as in a threaded connection. An anchor member 404C can be provided with a threadless distal portion. Such an implant can be used to secure in bone where ingrowth provides sufficient securement to the patient's bone or where the bone is too brittle to support a threaded anchor member. The anchor member 404C provides the threaded section <NUM> immediately adjacent to the distal portion thereof. As a result, the anchor member 404C is able to secure to any of the baseplates herein by virtue of the threads <NUM>. When the threads <NUM> of the anchor member 404C are fully engaged with a baseplate, further rotation of the baseplate relative to the anchor member 404C will be prevented by the proximal face of the threadless longitudinal portion 408C. Further rotation of a baseplate will result in rotation of the anchor member 404C in the bone. Such further rotation is acceptable because the longitudinal portion 408C is not threaded and thus is not secured to the bone at this stage of the procedure. The anchor member 404C is suitable where less precision is required in rotation alignment of the corresponding baseplate.

A method of using the glenoid implant <NUM> can include a plurality of steps, in addition to the method of assembling the glenoid implant <NUM> described above. The surgeon may select one or more of the plurality of steps. Further, a manufacturer providing a glenoid implant can provide instructions for one or more of the plurality of steps.

In one embodiment, a method of using a glenoid implant comprises selecting a preferred baseplate and/or preferred anchor member from a plurality of anchor members such as anchor members <NUM>, 104A-104E, <NUM> and/or a plurality of baseplates such as baseplates <NUM>, 108B-<NUM>, <NUM> described above, to best suit the patient. For example, any of the baseplates <NUM>, 108B-<NUM>, <NUM> and/or the anchors <NUM>, 104A-104E, <NUM> can be selected based upon the shape of the prepared bone. The baseplates and/or anchors can also be selected based on patient anatomy. For example, a baseplate could be selected that has holes arranged to be positioned above underlying scapular bone. Or a baseplate could be selected that has holes arranged to be positioned above underlying high quality, e.g., high density, bone. As discussed above with reference to <FIG> and <FIG>, the baseplate can have a variety of different bone engaging surfaces <NUM>, <NUM>, <NUM>, <NUM><NUM>, and configurations in order to best suit the patient. Further, the surgeon may select from a variety of bone anchors, such as those shown in <FIG>, <FIG>, and <FIG>. The plurality of anchor members can include different diameters of the longitudinal portion, wherein the bone anchor is selected based on the best fit with the anatomic structure of the patient, specifically the best fit in accordance with the glenoid that was removed. As noted above, the bottom loaded design (e.g., where the anchor member is inserted in the distal end <NUM> of the baseplate) permits the longitudinal portion and the external lateral surface of the anchor member to have a larger diameter than the diameter of one or more of the following: the second aperture, the first aperture, the lumen, and the central protrusion, which is an advantage for revision cases where much glenoid bone is typically removed. Further, the surgeon can make this selection after exposing the shoulder joint and inspecting the patient's anatomy. The bone anchors in the kit can have different thread pitch, lengths and diameters of the longitudinal portion, and integral components such as those to promote bony ingrowth, as shown in <FIG>.

After selecting a preferred anchor member and a preferred baseplate, the surgeon or other practitioner may attach the anchor member to the baseplate. For example, a surgeon may insert the proximal head <NUM> of any of the anchor members <NUM>, 104A-104E into the first aperture <NUM> of any of the baseplates <NUM>, 108B-<NUM>. This insertion can result in coupling the anchor member <NUM>, 104A-104E to the baseplate <NUM>, 108B-<NUM>. The proximal head <NUM> is inserted from the distal end <NUM> of the baseplate <NUM>, 108B-<NUM> into the first aperture <NUM>. The proximal head <NUM> does not traverse the second aperture <NUM>. The longitudinal portion <NUM>, 216A-216E of the anchor member <NUM>, 104A-104E remains distal to the baseplate <NUM>, 108B-<NUM> when the proximal head <NUM> of the anchor member <NUM>, 104A-104E is inserted into the first aperture <NUM> of the baseplate <NUM>, 108B-<NUM>. The longitudinal portion <NUM>, 216A-216E of the anchor member <NUM>, 104A-104E is not inserted into the first aperture <NUM>. The longitudinal portion <NUM>, 216A-216E of the anchor member <NUM>, 104A-104E is not inserted into the second aperture <NUM>. The longitudinal portion <NUM>, 216A-216E of the anchor member <NUM>, 104A-104E remains outside the confines of the baseplate <NUM>, 108B-<NUM> during coupling of the anchor member <NUM>, 104A-104E to the baseplate <NUM>, 108B-<NUM>. During coupling, the longitudinal portion <NUM>, 216A-216E extends distally.

As shown in <FIG>, an anchor member (such as anchor member <NUM>) with a baseplate pre-attached (such as baseplate <NUM>) can be inserted into a bone such as the scapular glenoid. It will be appreciated that although certain embodiments described herein involve the surgeon or practitioner pre-attaching the anchor member and baseplate before inserting the anchor member into bone, in other embodiments, the anchor member may be inserted separately from the baseplate. For example, an anchor member <NUM> may be at least partially seated or fully seated within the bone before the proximal head <NUM> of the anchor member <NUM> is inserted into the first aperture <NUM> of the baseplate <NUM>. In yet other embodiments, an anchor member and a baseplate may come pre-attached by the manufacturer.

With reference to <FIG>, as the surgeon prepares the patient for the implantation of the glenoid implant <NUM>, the surgeon first pierces a hole in the glenoid, typically the hole being slightly smaller than the diameter of the anchor member <NUM>. In one embodiment, the surgeon rotates the anchor member <NUM> into the glenoid using a tool designed to mate with the cavity <NUM> of the anchor member, e.g., with a hexagonal tip. This tool may be inserted through the lumen <NUM> in the baseplate when the baseplate is pre-attached to the anchor member. The self-tapping threads of the external lateral surface <NUM> of the anchor member <NUM>, if provided, permit the anchor member to be driven into the bone, optionally into the pre-formed hole. The surgeon can insert a guide wire into the bone in combination with a cannulated anchor member. The guide wire can facilitate placement of the anchor member with respect to the bone.

In some methods, a hole is made in the glenoid of a diameter of the central protrusion <NUM> of the baseplate <NUM> in order to accommodate the central protrusion <NUM> when the anchor member is fully seated in the bone. One method step includes shaping the bone to match the distal surface <NUM> of the baseplate <NUM>. The hole in the glenoid and the shaping of the bone may be done to accommodate the shapes of any of the other baseplates (e.g., baseplates 108B-<NUM> and <NUM>) described herein.

In certain embodiments the anchor member is pre-attached to the baseplate. In other embodiments, the anchor member is or can be attached to the baseplate by the surgeon during implantation.

After advancing the anchor into the bone such that the baseplate is adjacent to the glenoid the anchor member can be rotated (e.g. driven into the bone) without corresponding rotation of the baseplate. These arrangements allow the surgeon to position the baseplate relative to bone, specifically anatomical features of the bone, and maintain that position as the bone anchor member is rotated further into the bone to frictionally secure the baseplate to the bone). In some embodiments, the baseplate <NUM> is held in a desired orientation when the anchor member <NUM> is driven into the bone. In some embodiments, the baseplate <NUM> is maintained in a desired orientation by tools, as described below.

Referring now to <FIG>, in some methods tools are used to maintain the orientation of the baseplate <NUM> relative to the bone. In one embodiment, a cannula <NUM> is configured to interact with the baseplate <NUM>. In some embodiments, the cannula <NUM> has two radially extending legs <NUM>, <NUM>. The radially extending legs <NUM>, <NUM> permit the cannula <NUM> to be a smaller diameter than the diameter of the baseplate <NUM>. In some embodiments, the radially extending legs <NUM>, <NUM> include a distal feature that mates with a feature on the proximal end <NUM> of the baseplate <NUM>, for instance with tool engaging grooves <NUM> shown in <FIG>. In some embodiments, the radially extending legs <NUM>, <NUM> may extend, and partially cover the holes <NUM>, <NUM>. In some embodiments, the cannula <NUM> is sized to accept an inner cannula <NUM>. The inner cannula <NUM> can have multiple functions in some embodiments. The inner cannula <NUM> can be configured to assist in docking and un-docking the legs <NUM>, <NUM> with the baseplate <NUM>. For example, the outer profile of the inner cannula <NUM> can be larger than the inner profile of the outer cannula <NUM> near the distal end of the legs <NUM>, <NUM>. As the inner cannula <NUM> is advanced distally in the outer cannula <NUM> the outer surface of the inner cannula <NUM> spreads the legs <NUM>, <NUM>. Another function for the inner cannula <NUM> in some embodiments is to provide access for a driver therethrough to mate with the cavity <NUM> in the proximal head <NUM> of the anchor member <NUM>. The inner cannula <NUM> can have an inner lumen to provide such access. Thus, the driver can be used to insert the anchor member <NUM> into the bone while the cannula <NUM> maintains the rotational orientation of the baseplate <NUM>. The cannula <NUM> may further be used to rotate baseplate <NUM> to a desired orientation with respect to the bone.

In some embodiments, the baseplate <NUM> is rotated to align the holes <NUM>, <NUM> (shown in <FIG>) with anatomic features of the patient. In some embodiments, the baseplate <NUM> is rotated to align the bone engaging surface <NUM> with anatomic features of the patient. When the baseplate <NUM> is coupled to the anchor member <NUM>, the baseplate <NUM> is freely rotatable with respect to the anchor member <NUM>. The baseplate <NUM> can be rotated and orientated without adjusting the rotational position of the anchor member <NUM>. The anchor member <NUM> can be rotated and orientated without adjusting the rotational position of the baseplate <NUM>. In some embodiments, the baseplate <NUM> is rotated after the anchor member <NUM> is partially or fully driven into the bone. In some embodiments, the baseplate <NUM> is rotated before the anchor member <NUM> is driven into the bone.

Following proper orientation of the baseplate <NUM> relative to the bone, the surgeon can fully seat anchor member <NUM> into the bone using the driver. After the anchor member <NUM> is fully seated in the bone and the baseplate <NUM> is properly oriented relative to the bone, or peripheral anchors or screws <NUM> such as shown in <FIG> may be inserted into holes <NUM> and <NUM> provided in the baseplate <NUM>. In some embodiments, perimeter anchors <NUM> are inserted from the proximal end <NUM> of the baseplate <NUM> to the bone engaging surface <NUM> of the baseplate <NUM>, or through the baseplate <NUM>. This is the opposite direction the anchor member <NUM> is inserted into the baseplate <NUM>.

<FIG> show variations of an advantageous peripheral screw assembly <NUM> of the glenoid implant <NUM>. The peripheral screw assembly <NUM> includes the baseplate <NUM>, an internal member <NUM> and a peripheral screw <NUM>. The internal member <NUM> is disposed between an outer periphery <NUM> of the baseplate <NUM> and the central protrusion <NUM>.

<FIG> shows an aperture <NUM> that extends through the baseplate <NUM> adjacent to the outer periphery <NUM>. The aperture <NUM> extends from a proximal surface <NUM> of the baseplate <NUM> to a distal portion <NUM> thereof. The distal portion <NUM> can be a side of the baseplate <NUM> that engages the bone when the baseplate <NUM> is applied to the patient. In <FIG> one of the apertures <NUM> is labeled and another aperture <NUM> is shown with a peripheral screw <NUM> disposed therein, but not labeled for clarity. The internal member <NUM> is disposed in the aperture <NUM> of the baseplate <NUM>. <FIG> shows the internal member <NUM> having an internal threaded surface <NUM>. The internal threaded surface <NUM> is disposed within the aperture <NUM>.

<FIG> shows that in one embodiment, the internal member <NUM> has a C-shaped configuration including a peripheral wall <NUM>. The peripheral wall <NUM> extends around a lumen <NUM>. The lumen <NUM> extends along an axis L. A gap <NUM> is provided in the wall <NUM>. The gap <NUM> provides for flexing and movement of the internal member <NUM> when disposed in the baseplate <NUM>. The outer surface <NUM> of the wall is configured to permit rotation of the internal member <NUM> within the aperture <NUM>. For example, the outer surface can be curved and even at least partially spherical in some embodiments to move easily in the aperture <NUM> prior to being secured into a selected orientation as discussed below. The internal threaded surface <NUM> has a thread-start <NUM> disposed thereon. As discussed above, in this context, a thread-"start" is a broad term that includes either end of a thread regardless of whether the end is initially threaded into another structure. In some embodiments, the internal threaded surface <NUM> has a plurality of thread-starts <NUM> disposed therein. <FIG> shows an embodiment with four thread-starts. Two of the thread-starts <NUM> are shown in the perspective view and an additional two thread-starts are disposed on a portion of the wall opposite to the thread-starts that are shown. In other embodiments, there can be six, eight or ten or any other number of thread-starts.

The internal member <NUM> can have other features disposed on the outside wall thereof. A protrusion <NUM> can be disposed on the outside wall to engage a corresponding recess in the aperture <NUM> of the baseplate. The protrusion <NUM> allows the internal member <NUM> to rotate but prevents the member from being dislodged from the aperture <NUM>. The internal member <NUM> can have flats <NUM> disposed on the external wall. The flats make the internal member <NUM> more flexible such that it can be deflected to a secured configuration as discussed below.

The peripheral screw assembly <NUM> includes the peripheral screw <NUM> configured to be placed through the aperture <NUM>. The screw <NUM> has a proximal end <NUM>, a distal end <NUM>, and a body <NUM> that extends along the length thereof. The proximal end <NUM> can include a head <NUM> that has a tool engagement feature on an end and a tapered portion <NUM> projecting distally from the end. The screw <NUM> has an external threaded surface <NUM>. The external threaded surface <NUM> includes a thread-start <NUM> disposed at the distal end <NUM>. Accordingly, the external threaded surface <NUM> includes a thread-start <NUM> disposed near the proximal end <NUM> adjacent to the tapered portion <NUM> of the head <NUM>.

<FIG> show that the peripheral screw <NUM> includes profile with a diameter that is not constant along the length of the body of the screw. The screw <NUM> has a proximal portion <NUM> with a larger diameter section and a distal portion <NUM> with a smaller diameter section. The diameter of the screw <NUM> is enlarged, and may be stepped or changed in diameter in some embodiments adjacent to the proximal end <NUM> of the screw <NUM>. The screw <NUM> preferably has the same thread form in the proximal portion <NUM> and in the distal potion <NUM>. For example, the thread pitch can be the same in the proximal and distal portions <NUM>, <NUM>. The constant thread form in combination with the threading of internal member <NUM> enables the screw <NUM> to be advanced at a constant rate in both the proximal and distal portions <NUM>, <NUM>.

In one embodiment, the internal member <NUM> has a first number of thread-starts <NUM> disposed on the internal threaded surface <NUM>. The number of thread-starts is greater than the number of thread-starts on the disposed on the external threaded surface <NUM> of the anchor member <NUM>. This enables the screw <NUM> to be more rapidly advanced through the internal member <NUM>. In one embodiment, the glenoid implant <NUM> is provided with the internal member <NUM> having two times the number of thread-starts <NUM> as the number of thread-starts <NUM> on the anchor member <NUM>.

<FIG> shows partial advancement of the peripheral screw <NUM> through the internal member <NUM>. In this position, the gap <NUM> of the member <NUM> is not significantly expanded by the presence of the screw. As a result, the internal member is permitted to move to some extent allowing the trajectory of the aperture <NUM> and accordingly the screw <NUM> to be adjusted relative to the baseplate.

<FIG> shows full advancement of the peripheral screw <NUM> through the internal member <NUM>. In this position, the proximal portion <NUM> is disposed within the internal member <NUM>. The larger diameter of the proximal portion <NUM> causes the internal member <NUM> to expand within the aperture <NUM>. When the screw <NUM> is in this position, the gap <NUM> is enlarged to an extent sufficient to cause the peripheral wall <NUM> to be urged into secure engagement with an inside of the baseplate <NUM>. The secure engagement can include a high friction force being applied between these walls of the implant <NUM> such that movement of the aperture <NUM> is not possible or is minimal. By securing the orientation of the internal member <NUM> there is less play in the implant <NUM> making the implant less prone loosening after being secured to the scapula.

In some embodiments, after the anchor member and baseplate are attached to the bone, the locking structure <NUM> may be used to further secure the anchor member relative to the baseplate and to attach the glenosphere to the baseplate. For example, after the anchor member <NUM> shown in <FIG> has been inserted into the bone, the baseplate <NUM> is in the desired orientation with respect to the patient, and the perimeter anchors <NUM> have been inserted, the rotation of the anchor member <NUM> with respect to the baseplate <NUM> can be restricted via the locking structure <NUM>. With the locking structure <NUM> already assembled as described with respect to <FIG> above, and either with or without the glenosphere <NUM> attached to the threaded member <NUM>, the locking screw <NUM> is inserted into the second aperture <NUM> of the baseplate which has the threaded surface <NUM>. The locking screw <NUM> is rotated until the locking screw <NUM> applies a force on the proximal head <NUM> of the anchor member <NUM>. In some embodiments, the locking screw <NUM> enters a cavity <NUM> in the proximal head <NUM> of the anchor member <NUM>. In some embodiments, the force interacts with the member <NUM> to prevent rotation of the anchor member <NUM> with respect to the baseplate <NUM>. After application of force by the locking screw <NUM>, the anchor member <NUM> is prohibited from axial translation and rotation with respect to the baseplate <NUM>.

With the locking structure <NUM> in place, a glenosphere <NUM> such as shown in <FIG> and <FIG> may be attached to the baseplate <NUM>. In one embodiment, the glenosphere <NUM> may have already been attached to the threaded member <NUM> when the locking screw <NUM> is inserted into the cavity <NUM> in the proximal head <NUM> of the anchor member <NUM>. In another embodiment, the glenosphere <NUM> may be attached to threaded member <NUM> after the locking screw <NUM> is inserted into the cavity <NUM>. In some embodiments, the lateral surface <NUM> of the baseplate <NUM> is tapered and the interior surface <NUM> of the glenosphere <NUM> is tapered. When the glenosphere <NUM> moves distally, the interior surface <NUM> engages with the lateral surface <NUM> of the baseplate <NUM>. In some embodiments, the interior surface <NUM> and the lateral surface <NUM> form a Morse taper.

In some embodiments, the locking screw <NUM> simultaneously applies a force to the anchor member <NUM> and the glenosphere <NUM> when the locking screw <NUM> is advanced through the second aperture <NUM>. In some embodiments, the glenoid implant <NUM> is dimensioned so that the locking screw <NUM> applies a force to the proximal head <NUM> of the anchor member <NUM> simultaneously with the glenosphere <NUM> interior surface <NUM> mating with the lateral surface of the baseplate <NUM>. In this way, the locking screw <NUM> creates a downward force on the anchor member <NUM> and creates a downward force on the threaded member <NUM> which is coupled to the glenosphere <NUM>. The downward force causes the interior surface <NUM> and the lateral surface <NUM> to engage. In some embodiments, the locking screw <NUM> creates a push force on the glenosphere <NUM> and/or a pull force on the baseplate <NUM>.

As illustrated in <FIG>, the compression washer <NUM> provided between the proximal head <NUM> of the locking screw <NUM> and the baseplate <NUM> may be utilized to prevent micromotion. The compression washer <NUM> provides resistance against backout when the locking screw <NUM> creates a push force on the anchor member <NUM>. The compression washer <NUM> is designed to fill the space between the proximal head <NUM> of the locking screw <NUM> and the threaded member <NUM> as the locking screw <NUM> creates a push force on the glenosphere <NUM> and/or pull force on the baseplate <NUM>. The placement and use of the compression washer <NUM> facilitates the rigidity of the glenoid implant <NUM>, and further prevents rotation, translation and/or micromotion of the anchor member <NUM> with respect to the baseplate <NUM>. Further, preventing micromotion involves no additional step from the current procedure of securing a locking member.

In some embodiments, a bone graft (not shown) may be placed into the bone. The bone graft can be attached to or disposed about any of the surfaces or portions of the baseplates described herein including the distal surface <NUM>, distal end <NUM>, the bone engaging surface <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, the central protrusion <NUM>, <NUM>, or the longitudinal portion <NUM>, 216A-216E of the anchor member <NUM>, 104A-104E or any other feature that would benefit from bony ingrowth. Allowing the anchor member <NUM>, 104A-104E to be driven into the bone independently of rotation of the baseplate <NUM>, 108B-<NUM> causes less wear and stress on the bone graft during insertion. In some embodiments, the anchor member <NUM>, 104A-104E is freely rotatable with respect to the bone graft. In some embodiments, the bone graft is coupled to the baseplate <NUM>, 108B-<NUM> and rotates when the baseplate <NUM>, 108B-<NUM> rotates but not when the anchor member <NUM>, 104A-104E rotates. In some embodiments, the bone graft is inserted after the anchor members <NUM>, 104A-104E is fully or partially seated within the bone.

Claim 1:
A glenoid implant for a shoulder prosthesis comprising:
an anchor member (<NUM>; <NUM>) comprising a longitudinal portion (<NUM>) configured to be secured to a bone and a proximal head (<NUM>; <NUM>) comprising an external threaded surface (<NUM>; <NUM>);
a baseplate (<NUM>; <NUM>) comprising a proximal end (<NUM>) and a distal end (<NUM>; <NUM>), wherein the distal end comprises a first aperture (<NUM>; <NUM>) sized to accept the proximal head (<NUM>; <NUM>) of the anchor member (<NUM>; <NUM>), the first aperture comprising an internal threaded surface (<NUM>; <NUM>) and a space (<NUM>; <NUM>) disposed proximal of the internal threaded surface;
characterized in that when the external threaded surface (<NUM>; <NUM>) of the proximal head (<NUM>; <NUM>) is disposed in the space (<NUM>; <NUM>) proximal of the internal threaded surface (<NUM>; <NUM>) of the first aperture (<NUM>; <NUM>) the anchor member (<NUM>; <NUM>) is restrained against axial translation with respect to the baseplate (<NUM>; <NUM>) but is rotatable with respect to the baseplate.