Patent Description:
The shoulder joint is a complex joint with the scapula, clavicle and the humerus all coming together to enable a wide range of movement, at least in a properly functioning joint. In a properly functioning shoulder joint the head of the humerus fits into a shallow socket in the scapula, typically referred to as the glenoid. Articulation of the shoulder joint involves movement of the humeral head in the glenoid, with the structure of the mating surfaces and surrounding tissues providing a wide range of motion.

The shoulder joint can undergo degenerative changes caused by various issues, such as rheumatoid arthritis, osteoarthritis, rotator cuff arthroplasty, vascular necrosis or bone fracture. When severe joint damage occurs and no other means of treatment is found to be effective, a total, partial, or reverse shoulder replacement or reconstruction may be necessary. Total shoulder replacements can involve a humeral prosthetic, including a stem and a head portion used to replace the natural humeral head. Total shoulder replacements will also typically involve resurfacing of the glenoid with a prosthetic implant. The glenoid implant generally will include an articulating cup shaped to receive the prosthetic humeral head. A reversal shoulder replacement (arthroplasty) involves a different set of humeral and glenoid replacement prosthetics. In a reverse shoulder the humeral component includes a cup shaped articular surface attached to a stem implanted into the humerus, while a spherical glenoid component is used to provide an articular surface for the humeral cup. <CIT> discloses an adjustable humeral cutting guide for defining a cutting plane for a saw in a bone in which a positioning structure is located includes a clamp, a saw guide, and an orientable coupling. The clamp is configured to be secured to the positioning structure. The saw guide includes a slot formed therein sized to receive a saw and limit the saw to cutting in a specific plane. The orientable coupling is mounted to the clamp and the saw guide. The orientable coupling is configured to adjust the saw guide at a selectable anterior/posterior angle and a selected medial/lateral angle.

Various techniques have been developed for resecting the humeral head to facilitate implantation of the humeral component. One such technique, utilizes an intramedullary rod or reamer to mount a cut block to facilitate resecting the humeral head. One problem to be solved by the present systems and instruments was known instrument assemblies utilized several knobs and thumbscrews. These knobs and thumbscrews can be cumbersome to loosen to manipulate the cut block to a different desired position. They also must then be retightened once the cut block is in the desired position. Additionally, previous systems and instruments constrained movement of the cut block to allow for movement only along one direction (generally along a boom arm). This can leave undesired gaps between the cut block face and a face of the humerus. However, the present instruments and systems can provide the surgeon with more flexibility in repositioning the cut block used in performing resection of the humerus. Rotational movement of the cut block can be achieved with the present instruments and systems. This provides the surgeon with improved ability to adjust the cut block to assist in resection of the humerus. Other instruments in the system are disclosed and provide the surgeon with other advantages such as improved efficiency through reduced complexity and reduced time to perform the procedure. For example, the present systems and instruments provide for pins that can be angled relative to one another and pins that can be placed at the resection surface. These configurations can facilitate better fixation of the cut block to the humerus reducing the likelihood the block would vibrate or shift positions in performing the guided resection.

The instrument assembly according to the invention is defined in claim <NUM>. Further embodiments of the invention are recited in the dependent claims.

As discussed herein, orthopedic systems and apparatuses are disclosed herein that facilitate resection and/or sizing of tissue. It should be noted that although described in reference to a humerus, the apparatuses and systems of the present application are applicable to other bones or bone portions including the femur or tibia, for example.

<FIG> shows a system <NUM> that includes cut guide assembly <NUM> according to one example. The cut guide assembly <NUM> can used to resect a head <NUM> of a humerus <NUM> as further discussed an illustrated herein. The system <NUM> can further include a reamer <NUM> and other components as further discussed herein. The cut guide assembly <NUM> can be mounted in position relative to the humerus <NUM> via the reamer <NUM>. The cut guide assembly <NUM> can include various components including a clamp <NUM>, a first arm <NUM>, a carriage <NUM>, a cut block <NUM> and indicia <NUM>.

As shown in <FIG>, the reamer <NUM> can be inserted into the humerus <NUM> along a longitudinally extending intramedullary recess thereof. The clamp <NUM> can be configured to couple the remainder of the cut guide assembly <NUM> to the reamer <NUM>. The first arm <NUM> can couple to one or more parts of the clamp <NUM>. The first arm <NUM> can project away from the reamer <NUM> in a cantilevered manner. The carriage <NUM> can couple with the first arm <NUM>. The carriage <NUM> can be selectively moveable along a longitudinal length of the first arm <NUM>. The carriage <NUM> can include a portion thereof that extends away from the first arm <NUM> generally distally and posteriorly toward the head <NUM> of the humerus <NUM>. The cut block <NUM> can be coupled to the carriage <NUM> at an end thereof that opposes an end that is coupled to the first arm <NUM>. As discussed further herein, the cut block <NUM> can be selectively rotatable relative to the carriage <NUM>. Such configuration for the cut block <NUM> can be facilitated by one or more magnets and/or other mechanisms as further discussed herein. The indicia <NUM> can include one or more rods <NUM> that can be mounted to indicate varus orientation of the cut guide assembly <NUM>. One of the one or more rods <NUM> can be angled to be aligned with the lower forearm of the patient, for example.

The clamp <NUM> can be selectively movable along a shaft of the reamer <NUM> and can be lockable thereto. As shown in <FIG>, the clamp <NUM> can include a shaft clamp <NUM> and locking mechanism <NUM>. The shaft clamp <NUM> can comprise a sleeve or C-clamp type device configured to receive portions of the reamer <NUM>. The shaft clamp <NUM> can be sized to be moveable along the shaft of the reamer <NUM>. The locking mechanism <NUM> can extend through the shaft clamp <NUM> to selectively engage the reamer <NUM> as further discussed and illustrated herein. The clamp <NUM>, via the locking mechanism <NUM> can connect the clamp <NUM> and a remainder of the cut guide assembly <NUM> to the reamer <NUM> when a desired position is achieved.

The shaft clamp <NUM> can be connected to the first arm <NUM>. According to some examples, such connect can be an integral connect or via a weld connection. However, another type of connection, such as a keyway, fastener, etc. is contemplated. According to some examples, the first arm <NUM> can have an open frame design and can be configured to receive portions of the locking mechanism <NUM> therein as further discussed subsequently. The first arm <NUM> can extend radially outwards from the reamer <NUM> to an open end.

The carriage <NUM> moveable relative to the first arm <NUM> along a longitudinal length thereof. The carriage <NUM> can include a bracket <NUM>, a second arm <NUM> and a retainer <NUM>. The bracket <NUM> can comprise an open ended feature configured to receive the first arm <NUM>. The bracket <NUM> can include a connection feature configured to lock a position of the carriage <NUM> relative to the first arm <NUM> as further discussed herein. The second arm <NUM> can couple with the bracket <NUM> and can extend outwards therefrom and from the first arm <NUM>. The second arm <NUM> can be configured to generally distally in a spaced manner generally parallel with a longitudinal length of the reamer <NUM>. The second arm <NUM> can couple with the retainer <NUM>. The retainer <NUM> can be selectively positioned by the clamp <NUM> and the carriage <NUM> so as to be positioned generally outwards (anterior) of the head <NUM> of the humerus <NUM> as shown in <FIG>.

The retainer <NUM> can be configured to capture the cut block <NUM> therein to mount the cut block <NUM>. However, the retainer <NUM> can be configured to capture the cut block <NUM> in a moveable manner. For example, the cut block <NUM> can be rotatable relative to the retainer <NUM> and other parts of the carriage <NUM> as further discussed herein.

As shown in <FIG>, the system <NUM> can include a plurality of pins <NUM> or other features such as bone screws, etc. These can be configured to be driven or otherwise inserted into the head <NUM> of the humerus <NUM> by a driver <NUM> or other instrument. The plurality of pins <NUM> can be directed by slots or apertures in the cut block <NUM> as illustrated.

As a result of the components and features described herein, the cut guide assembly <NUM> can be selectively movable along the reamer as shown by arrow A1. The carriage <NUM> and remainder of the cut guide assembly <NUM> can be moveable along the first arm <NUM> as shown by arrow A2. The cut block <NUM> can be rotatable and moveable relative to the carriage <NUM> and humerus <NUM> as shown by arrow R1. More particularly, the cut block <NUM> can be moveable in a constrained manner toward and away from the head <NUM> as guided by the retainer <NUM> as further discussed herein. Additionally, the cut block <NUM> can be rotatable relative to the retainer <NUM>.

<FIG> shows an enlarged cross-sectional view of portions of the first arm <NUM> and the carriage <NUM>. <FIG> shows the bracket <NUM> can included a spring finger <NUM>. The spring finger <NUM> can be biased or otherwise configured to interfere with or otherwise engage the first arm <NUM>. This allows constant friction to be applied to the first arm <NUM>. This arrangement can improve vibration resistance of the carriage <NUM>. The spring finger <NUM> can engage with an outer surface of the arm <NUM>. Using the spring finger <NUM>, the carriage <NUM> can be locked or otherwise coupled to the first arm <NUM>. This can maintain relative positioning between the two components. The carriage <NUM> can be moved relative to the first arm <NUM> by disengaging the spring finger <NUM> from engagement with the first arm <NUM>. This can allow the bracket <NUM> to be slide or otherwise moved along a longitudinal length or the first arm <NUM>.

<FIG> shows a perspective view of the clamp <NUM> and first arm <NUM> with some components of the clamp <NUM>, in particular, the locking mechanism <NUM> exploded. As previously discussed and illustrated, the clamp <NUM> can include the shaft clamp <NUM> configured to receive the reamer. <FIG> shows the first arm <NUM> can have an open frame design with a cavity <NUM> formed by walls of the frame.

The locking mechanism <NUM> can include a lever <NUM>, a leaf spring <NUM> and a plunger <NUM>. The lever <NUM> can couple to the leaf spring <NUM> at a first end thereof by a pin <NUM> or other known feature or fastener such as a bolt, etc. The lever <NUM> can also be pivotally movable relative to the first arm <NUM> and can be pivotally coupled thereto such as via a second pin <NUM>. The lever <NUM> can be configured as a handle to be graspable. The lever <NUM> can be configured to actuate the leaf spring <NUM> and the plunger <NUM> as further described. According to some examples, the lever <NUM> can be configured as a camming mechanism to bring the plunger <NUM> into engagement with the reamer <NUM> (<FIG>).

As shown in <FIG>, the leaf spring <NUM> can be an elongate rod or member with a relatively thinner lateral thickness as compared with a longitudinal length. The leaf spring <NUM> can be configured to be received in the <NUM> of the first arm <NUM>. The leaf spring <NUM> can be slightly bowed along the longitudinal length thereof. Bowing of the leaf spring <NUM> can increase with engagement of the plunger <NUM> against the reamer as further illustrated herein.

The plunger <NUM> can connect with the leaf spring <NUM> at a second end thereof. This second end can oppose the first end that is connected to the lever <NUM>. The plunger <NUM> can be configured to selectively engage the reamer as further illustrated herein. Engagement of the reamer by the plunger <NUM> can lock a position of the clamp <NUM> and the arm <NUM> relative to the reamer as previously discussed.

<FIG> show operation of the clamp <NUM>, in particular, the locking mechanism <NUM>. In <FIG>, portions of the first arm <NUM> and carriage <NUM> are removed to better illustrate operation of the locking mechanism <NUM>. <FIG> and <FIG> show the locking mechanism <NUM> in the locked position with the lever <NUM> rotated to bring the plunger <NUM> into engagement with a shaft <NUM> of the reamer <NUM>. <FIG> shows the locking mechanism <NUM> in an unlocked position with the lever <NUM> rotated to bring the plunger <NUM> out of engagement with the shaft <NUM> of the reamer <NUM>.

In <FIG>, with the lever <NUM> in the unlocked position, the plunger <NUM> is positioned via the leaf spring <NUM> so as to be spaced from the shaft <NUM> of the reamer <NUM>. In <FIG>, the lever <NUM> is rotated to the locked position, this moves the plunger <NUM> into engagement with the shaft <NUM> of the reamer <NUM>.

Additionally, as shown in <FIG>, in the locked position, the leaf spring <NUM> can bow or otherwise deflect laterally outward relative to a longitudinal length as compared with the unlocked position. The configuration of the leaf spring <NUM> can provide for a more smooth or iterative application of force on the reamer <NUM> and reduced and/or smoother application of actuation force to rotate the lever <NUM>. The configuration of the clamp <NUM>, particularly using the leaf spring <NUM> facilitates vibration-resistant connection with the shaft <NUM> of the reamer <NUM>. The clamp <NUM> is configured to resist shaking loose or changing tension on the reamer <NUM> when the cut guide assembly is subjected to an oscillating saw blade.

The pin <NUM> can affix the leaf spring <NUM> to the lever <NUM> at a first end thereof. The first arm <NUM> and/or carriage <NUM> can be provided with a stop <NUM> to retain and/or halt lateral deflection of the leaf spring <NUM>. The shaft clamp <NUM> can have a passage <NUM> therein. The passage <NUM> can be configured to receive and retain the plunger <NUM> (i.e. the second end of the leaf spring <NUM>) even during deflection of the middle portion of the leaf spring <NUM> as shown in <FIG>. The passage <NUM> can extend through the shaft clamp <NUM> allowing the plunger <NUM> to selectively engage with the shaft <NUM> of the reamer <NUM>.

<FIG> and <FIG> show the carriage <NUM> in further detail. An interface between the carriage <NUM> and the cut block <NUM> can comprise a pair of interfaces designed for coupling the two components together. One interface can be mechanical and one can be magnetic. The mechanical interface can be between opposing undercuts (rails) in the bottom portion of the carriage <NUM> and a pair of closely-fitted lips on the cut block <NUM> (as shown in <FIG>). These features can accurately locate the cut block <NUM> at the correct angle as set by the carriage <NUM>. Basically, these interfaces can set the resection plane as defined by atop of the cut block <NUM>. However, these features can allow he cut block <NUM> to be free to rotate and/or to slide (or otherwise move) back and forth in the plane. However, the cut block <NUM> can be constrained to motion only in this plane as dictated by the orientation of the carriage <NUM> and the rails (see discussion below). The magnetic interface can hold the cut block <NUM> against the mating surface of the carriage <NUM>, with the force being defined by the magnetic field strength of the magnet(s) embedded into the carriage <NUM>.

<FIG> shows components previously discussed including the bracket <NUM>, the second arm <NUM> and the retainer <NUM>. <FIG> and <FIG> additionally illustrate further components and features of the retainer <NUM>. Thus, <FIG> and <FIG> show one or more magnets <NUM>, one or more inverted cups <NUM> and one or more wave springs <NUM>. The retainer <NUM> can include one or more recesses <NUM>, one or more rails <NUM> and one or more grooves <NUM>.

As shown in <FIG>, the retainer <NUM> can have the one or more recesses <NUM> configured to receive the one or more magnets <NUM>, one or more inverted cups <NUM> and one or more wave springs <NUM>. The one or more recesses <NUM> can be configured to position the assembly of the one or more magnets <NUM>, one or more inverted cups <NUM> and one or more wave springs <NUM> below or flush with a surface <NUM> of the retainer <NUM>.

The one or more inverted cups <NUM> can be configured to receive the one or more magnets <NUM> therein. The one or more inverted cups <NUM> can be welded or otherwise affixed to an interior of the one or more recesses <NUM>. The wave springs <NUM> can be seated in a bottom of the recesses <NUM> and can be configured to bias the one or more magnets <NUM> against an interior lid of the one or more inverted cups <NUM> as shown in <FIG>.

The retainer <NUM> can be shaped as a track having open opposing ends. The one or more rails <NUM> and the one or more grooves <NUM> can be positioned laterally relative to these openings. The one or more grooves <NUM> can be positioned distal of the one or more rails <NUM> adjacent the surface <NUM>. The one or more rails <NUM> can be shaped as hooks to couple with mating female features of the cut block. Similarly, the one or more grooves <NUM> can be shaped to receive and mate with male features of the cut block. It should be noted that the one or more grooves <NUM> and the one or more rails <NUM>, and indeed the shape of the retainer <NUM> can allow for generally anterior-posterior adjustment of the cut block. Furthermore, the one or more magnets <NUM>, the one or more grooves <NUM> and the one or more rails <NUM> can be configured to allow rotational adjustment of the cut block as previously discussed and illustrated relative to <FIG>.

<FIG> show the cut block <NUM> in further detail. The cut block <NUM> can be oriented by the remainder of the cut guide assembly to be adjacent (including slightly spaced or abutting the head <NUM>) of the humerus <NUM>. In particular, the cut block <NUM> can be oriented anterior of the head <NUM> and can be distal of a portion of the head <NUM>. Although the cut block <NUM> is shown as oriented diagonal extending proximal-distal and medial-lateral in <FIG> and <FIG> various other orientations for the cut block <NUM> are contemplated. As discussed previously, the cut block <NUM> can be rotatable relative to the humerus <NUM>, the reamer <NUM> and other portions of the cut guide assembly <NUM> as previously discussed and illustrated. It should be noted that according to some examples, once the cut block <NUM> is pinned as shown in <FIG>, the remainder of the cut guide assembly <NUM> can be removed.

The cut block <NUM> can include one or more portions thereof or can be entirely constructed of ferrous material. Alternatively, the cut block <NUM> can include one or more magnets configured to be attracted to the one or more magnets of the carriage. As shown in <FIG>, the cut block <NUM> can be shaped to be <NUM> degrees rotationally adjustable. Thus, in some implementations a bone interfacing side <NUM> of the cut block <NUM> as shown in <FIG> and <FIG> can be <NUM> degrees rotated in orientation so as to be reversed to be a bone opposing side. In such case, an opposing side <NUM> of the cut block <NUM> would become the bone interfacing side. The cut block <NUM> can also be configured for use on either a left humerus or a right humerus.

As shown in <FIG>, the cut block <NUM> can include a proximal or resection surface <NUM> and a plurality of apertures <NUM>. The plurality of apertures <NUM> can be configured to receive pins <NUM> or other features as shown in <FIG> and <FIG>. Some of the plurality of apertures <NUM> can have openings to the proximal or resection surface <NUM> that can allow portions of affixing pins to be exposed at the proximal or resection surface <NUM>. These exposed pins can aid in guiding resection of the humeral head <NUM> as shown in <FIG>. More particularly, a top tangent surfaces of all the pins along with the proximal or resection surface <NUM> can form one continuous, step-free, plane for the saw blade to traverse while the cut is being made.

As shown in <FIG>, a number of the plurality of apertures <NUM> can also be recessed a desired distance from the resection or proximal surface <NUM>. Various different aperture orientations including intersecting or non-aligned orientations for the apertures relative to one another are contemplated. These splayed apart apertures (rather than being parallel) can works to retain the cut block <NUM> against the humerus against oscillating saw blade vibrations. <FIG> additionally shows a base <NUM> having mating features such as lips <NUM> for the one or more grooves <NUM> and the one or more rails <NUM> of the retainer <NUM> (<FIG> and <FIG>) to facilitate coupling therewith.

The clamp <NUM> can eliminate the need for threaded thumbscrews or other mechanisms typically used with prior cut guide assemblies. Once the cut block <NUM> is in place and pinned, the clamp <NUM> can be loosened in a single motion. This can allow the remainder of the cut guide assembly <NUM> save the cut block to be removed without having to loosen or disengage other components as with the prior cut guide assemblies. The spring finger <NUM> can eliminate the need for another thumbscrew or other mechanism typically used with prior cut guide assemblies. The one or more magnets along with the configuration of the one or more grooves <NUM> and the one or more rails <NUM> of the retainer <NUM> can eliminate the need for yet another thumbscrew or other mechanism typically used with prior cut guide assemblies. Fitment between the one or more rails <NUM> of the retainer <NUM> and the cut block <NUM> allows the cut block <NUM> to be slid up adjacent to the humerus to give the minimum possible gap between the cut block <NUM> and the head <NUM>. Some of the plurality of apertures <NUM> with an opening to the resection or proximal surface <NUM> of the cut block <NUM> make the tops of the affixing pins an extension of the cut block <NUM> into the bone itself, which further improves resection flatness and accuracy. These open to the resection or proximal surface <NUM> plurality of apertures <NUM> also can serve as a "flatness gauge" for the cut, by allowing the surgeon to view any areas of the resection that the pin sides are not visible to be re-cut or the resection "polished" with the saw blade until the resection is flat. The indicia <NUM> including rods, which can be attached quickly and efficiently to every instrument in the system <NUM> that requires reference to the patient's forearm to set or check retroversion. These parts are versatile in that they can be used together for a <NUM> / <NUM> / <NUM> degree combination retroversion setup for either Left or Right hand surgeries, or the center <NUM> degree Rod can be used alone if desired.

The above description includes references to the accompanying drawings, which form a part of the detailed description. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more Examples thereof), either with respect to a particular example (or one or more Examples thereof), or with respect to other examples (or one or more Examples thereof) shown or described herein.

Geometric terms, such as "parallel", "perpendicular", "round", or "square", are not intended to require absolute mathematical precision, unless the context indicates otherwise. Instead, such geometric terms allow for variations due to manufacturing or equivalent functions. For example, if an element is described as "round" or "substantially round," a component that is not precisely circular (e.g., one that is slightly oblong or is a many-sided polygon) is still encompassed by this description.

The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more Examples thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment.

Claim 1:
An instrument assembly (<NUM>) for an orthopedic procedure, comprising:
a reamer (<NUM>); and
a cut guide assembly (<NUM>) configured to couple to the reamer, the cut guide assembly comprising:
a clamp (<NUM>) selectively movable along a shaft of the reamer and lockable thereto;
a first arm (<NUM>) projecting from the reamer;
a carriage (<NUM>) selectively moveable along a longitudinal length of the first arm; and
a cut block (<NUM>) coupled to the carriage via one or more magnets (<NUM>);
wherein the carriage includes a second arm (<NUM>) projecting away from the first arm and a retainer (<NUM>) configured to receive the one or more magnets therein;
further comprising one or more inverted cups (<NUM>) configured to receive the one or more magnets therein; and
further comprising one or more wave springs (<NUM>) configured to bias the one or more magnets against a lid of the one or more inverted cups.