Patent Application
20210085474
The present application relates to apparatuses and methods for humeral implants and for the adjustment of positioning and/or orientation of the same.
A typical anatomical shoulder joint replacement attempts to mimic anatomic conditions. For example, a humeral stem and a humeral head replacement are attached to the humerus of the arm and replace the humeral side of a shoulder joint that is arthritic, has suffered trauma or otherwise requiring replacement to improve the condition of the patient. The humeral head replacement can articulate with the native glenoid socket or with an opposing glenoid resurfacing device.
For more severe cases, a reverse reconstruction can be performed, which includes reversing the kinematics of the shoulder joint. A reverse shoulder prosthesis can be provided by securing a semi-spherical device (sometimes called a glenosphere) to the glenoid and implanting a humeral stem with a cavity capable of receiving the glenosphere.
Before implanting the humeral implant, it may be desirable to trial the humeral implant to determine an appropriate length of the stem, appropriate inclination angle of the articulating head, and/or size of the articulating head, or other characteristics of the implant. The trial humeral implant can be assembled and then inserted into the humerus. Afterwards, the entire trial implant can be removed, and the definitive humeral implant can be chosen and implanted in the bone.
Accordingly, there is a need for additional humeral stem assemblies that enhance a surgeon's ability to position and orient the assembly during implantation. A wider range of possible version adjustments, including finer version adjustments, can allow for increased precision in positioning the assembly and to more closely match an appropriate position for a particular patient. Such assemblies preferably include components and configurations that reduce, e.g., minimize stress risers while enhancing durability.
In one embodiment a humeral stem assembly is provided that includes a stem portion, a metaphyseal portion, and an intermediate spacer. The stem portion has a stem engagement feature that has a first plurality of teeth. The stem engagement feature is located on a superior end of the stem portion. The metaphyseal portion has a metaphyseal engagement feature. The metaphyseal engagement feature can include a second plurality of teeth. The metaphyseal engagement feature is located on an inferior end of the metaphyseal portion. The intermediate spacer has a first spacer engagement feature and a second spacer engagement feature. The first spacer engagement feature has a third plurality of teeth on an inferior end of the intermediate spacer. The second spacer engagement feature has a fourth plurality of teeth on a superior end of the intermediate spacer. The third plurality of teeth of the first spacer engagement feature is configured to engage with the first plurality of teeth of the stem engagement feature at a first interface. The fourth plurality of teeth of the second spacer engagement feature is configured to engage with the second plurality of teeth of the metaphyseal engagement feature at a second interface. A number of teeth of the third plurality of teeth differs from a number of teeth of the fourth plurality of teeth.
In another embodiment, a humeral stem assembly is provided that includes a stem and a metaphyseal portion. The stem has a first portion and a second portion. The first portion has a first end for insertion into a humerus and a second end opposite the first end. A first engagement feature is located on the second end of the first portion. The second portion has a first end that has a second engagement feature and a second end opposite the first end that has a third engagement feature. The metaphyseal portion has a fourth engagement feature. The fourth engagement feature is located on a first end of the metaphyseal portion. The metaphyseal portion is rotatable in a first direction about a longitudinal axis of the assembly to a plurality of discrete positions defined by engaging the fourth engagement feature with the third engagement feature. The second portion of the stem is rotatable in a second direction about the longitudinal axis to a plurality of discrete positions defined by engaging the second engagement feature with the first engagement feature. A version adjustment greater than zero and less than 10 degrees can be provided by a rotation of the metaphyseal portion in the first direction relative to the second portion of the stem and a rotation of the second portion of the stem in the second direction relative to the first portion of the stem.
In another embodiment a method of adjusting version of a humeral stem is provided. A metaphyseal portion, an intermediate portion, and a stem portion are assembled. The intermediate portion is slid into engagement with the stem portion at a first interface. The intermediate portion is slid into engagement with the metaphyseal portion at a second interface. Version of the humeral stem is adjusted by rotating the intermediate portion at the first interface to a discrete position in a first direction about a longitudinal axis of the implant. Version of the humeral stem is adjusted by rotating the metaphyseal portion at the second interface to a discrete position in a second direction about the longitudinal axis. The first direction is opposite the second direction. The version is adjusted by a non-zero angle less than an angular spacing between discrete positions defined at the first interface and at the second interface.
These and other features, aspects and advantages are described below with reference to the drawings, which are intended for illustrative purposes and should in no way be interpreted as limiting the scope of the embodiments. Furthermore, various features of different disclosed embodiments can be combined to form additional embodiments, which are part of this disclosure. In the drawings, like reference characters denote corresponding features consistently throughout similar embodiments. The following is a brief description of each of the drawings.
Humeral implants can include modular components. It may be desirable to be able to adjust the configuration of the assembly with a small number of modular components. For example, it would be advantageous to provide a great deal of adjustability of a biomechanical aspect of the assembled humeral implant, such as version, with a small number of components. It would be advantageous to be able to adjust version or another biomechanical aspect by small amounts, e.g., by non-zero amounts less than ten degrees. These adjustments can enable the humerus to have a proper orientation to the glenoid and/or to an articular component coupled with the glenoid.
I. Shoulder Joint Anatomy and Fine Version Adjustable Stem
As discussed further below, in some cases the humerus 52 may be fractured or otherwise damaged by trauma or disease such that a portion of the humerus 52 including the head 50 and a portion distal to the anatomic neck 62 has been removed or is not present. In such cases one portion of the stem 104 can be embedded in the remaining portion of the humerus 52 and another portion can extend proximally from the embedded portion.
The following embodiments illustrate how a fine degree of version adjustment can be provided in a stem for the humerus 52. These embodiments can be used in other orthopedic assemblies involving stems and similar structures where rotational orientation adjustment is useful.
II. Humeral Stem Assemblies
For example, each of the first portion 132, the humerus 12 and the metaphyseal portion 108 can include a lumen that extends therethrough. The lumens can be aligned such that a bolt member 124 can be advanced through the metaphyseal portion 108, into the intermediate spacer 112, and further into the first portion 132. As discussed further below, the bolt member 124 can be configured to be threaded into the first portion 132. The tooling interface 129 can enable a powered or manual driver to engage a proximal end of the bolt member 124 to advance threads at a distal end thereof into thread disposed in a distal portion of the humeral stem assembly 100, e.g., within a lumen 133 of the first portion 132.
The first portion 132 is coupled with the intermediate spacer 112. The intermediate spacer 112 is coupled with the metaphyseal portion 108. The first portion 132, intermediate spacer 112, and metaphyseal portion 108 are secured together in a suitable manner such as by securing the bolt member 124 in the central lumens thereof using the cap screw 130 or otherwise.
After the humeral stem assembly 100 has been assembled in the humerus 52 adjustments to biomechanical configuration of the humeral stem assembly 100 can be made. Such adjustments can include a version adjustment. In some cases, a fine version adjustment can be provided. Fine and other version adjustments are discussed below in connection with
After the humeral stem assembly 100 has been assembled and adjusted to the satisfaction of the surgeon a humeral assembly 90 can be provided by coupling a tray 92 with the humeral stem assembly 100. The tray 92 can include a taper on a distal side thereof and a concave recess on a proximal side thereof. The taper can be configured to be inserted into a recess formed in a proximal face of the metaphyseal portion 108. The taper and the recess can have corresponding conical configurations that facilitate an interference fit, such as by a Morse taper connection. The concave recess of the tray 92 can be configured to receive a mating projection of an insert 94 to be mated with the tray 92. The insert 94 is configured such that the mating projection is on a distal side thereof. The insert 94 can have a concave articular surface formed in a proximal side thereof. The concave articular surface of the insert 94 can be configured to articulate over a convex member configured to be coupled with the glenoid 58 of the scapula 54. The convex member is sometimes referred to as a glenosphere. The foregoing description and as depicted in
Although a reverse shoulder configuration is illustrated in
The second end 144 can include a first plurality of teeth 148. The first plurality of teeth 148 can be disposed at the proximal end of the first portion 132 of the stem 104. The first plurality of teeth 148 can be disposed to be proximally facing to enable the first portion 132 to mate with the intermediate spacer 112 as indicated by the arrow extending from the intermediate spacer 112 to the second end 144 of the first portion 132. The first plurality of teeth 148 can take any suitable configuration, as discussed further below. In some embodiments the first plurality of teeth 148 has planar edges that meet at linear edges. In some embodiments the first plurality of teeth 148 includes curved faces that meet at smooth curved peaks. Linear edge peaks provide excellent mating. Smooth curved peaks provide less stress concentration compared to that of the linear edge teeth.
The intermediate spacer 112 has a second spacer engagement feature 168 disposed at the second end 156 of the cylindrical body thereof. The second spacer engagement feature 168 can have a third plurality of teeth 172. The third plurality of teeth 172 can be disposed on a proximal facing side of the intermediate spacer 112. The third plurality of teeth 172 can have sharp or rounded configurations as discussed herein. The teeth of the third plurality of teeth 172 will be of a number different from the number of teeth of the second plurality of teeth 164. The spacing between the third plurality of teeth 172 is a different spacing than the spacing of the second plurality of teeth 164 in some embodiments. In one example the third plurality of teeth 172 includes thirty teeth and the second plurality of teeth 164 includes thirty-six teeth. In one example, the teeth of the third plurality of teeth 172 are spaced apart by twelve degrees and the teeth of the second plurality of teeth 164 are spaced apart by ten degrees. There can also be more or less teeth in the third plurality of teeth 172. For example, there can be about 20-35 teeth (e.g., there can be 22 teeth, 25 teeth, 30 teeth, 33 teeth, etc.). In other embodiments, a different angular spacing can be provided between the teeth of the third plurality of teeth 172. For example, there can be an angular spacing of about 10 to 18 degrees (e.g., there can be angular spacing of 12 degrees, 14.4 degrees, etc.) between teeth on the second spacer engagement feature 168 of the intermediate spacer 112.
The teeth of the metaphyseal engagement feature 184 can be of a different number of teeth than is the teeth of the first plurality of teeth 148. The teeth of the metaphyseal engagement feature 184 can be spaced apart by a different angular separation than are the teeth of the first plurality of teeth 148. As a result, the metaphyseal portion 108 can be rotated in a first direction relative to the stem 104 or to the intermediate spacer 112 by an angular amount that is different in magnitude from a relative rotation of the first portion 132 of the stem 104 relative to the intermediate spacer 112 or another portion (e.g., a proximal portion) of the humeral stem assembly 100.
The number of teeth at the first interface 116 can be different from the number of teeth at the second interface 120. Similarly, the angular spacing between adjacent teeth at the first interface 116 can be different from the angular spacing between adjacent teeth at the second interface 120. The difference between the angular spacing between adjacent teeth at one of the two interfaces and the angular spacing between adjacent teeth at another interface can be between 0 and 10 degrees (e.g., the difference in angular spacing can be 0.5 degrees, 2 degrees, 5 degrees, etc.).
The metaphyseal portion 108 has a proximal portion that is connectable to an articular component or assembly as discussed above.
A rigid connection can be made between the stem 104, the metaphyseal portion 108, and the intermediate spacer 112 by any suitable manner For example, a connector 122 can be provided that secures these components together. The connector 122 can be in the form of an assembly that provides for secure connections. The connector 122 can include a bolt member 124 with a threaded end 126. The threaded end 126 can include threads and also a taper 128. The bolt member 124 can include a tapered head 224 at the proximal end thereof. The bolt member 124 can include a tooling interface 129 (see
III. Methods of Fine Adjustment
Although it has been known to use teeth to secure components of a humeral assembly together such prior approaches did not enable fine biomechanical configuration adjustment.
After the initial version is confirmed the connector 122 can be used to secure the metaphyseal portion 108, the first portion 132 of the stem 104 and the intermediate spacer 112 together. Or if the version provided by the initial version 238 is not suitable an adjustment can be made.
In one embodiment, the mating teeth at the first interface 116 are offset by 10 degrees, e.g., by providing 36 equally spaced teeth at the first interface 116. The mating teeth at the second interface 120 are offset by 12 degrees, e.g., by providing 30 equally spaced teeth at the second interface 120. Thus, an anterior or posterior adjustment of 10 degrees can be provided by rotating the intermediate spacer 112 relative to the first portion 132 of the stem 104 by one tooth but not changing the relative positions of the metaphyseal portion 108 and the intermediate spacer 112. An anterior or posterior adjustment of 12 degrees can be provided by rotating the metaphyseal portion 108 relative to the intermediate spacer 112 by one tooth but not changing the relative positions of the intermediate spacer 112 relative to the first portion 132 of the stem 104. An adjustment of 20 or 24 degrees can be provided by adjusting in the same manner by two teeth.
Smaller, fine adjustments can be provided by the method illustrated by
In another embodiment, the mating teeth at the first interface 116 are offset by 14.4 degrees, e.g., by providing 25 equally spaced teeth at the first interface 116. The mating teeth at the second interface 120 are offset by 15 degrees, e.g., by providing 24 equally spaced teeth at the second interface 120. Larger or finer adjustment can be made by rotating one or both interfaces as discussed above. This configuration can provide 0.6 degree adjustment (or multiples thereof).
In another example, the teeth at the first interface 116 are spaced apart by 15 degrees and the teeth at the second interface 120 are spaced apart by 10 degrees. This enables adjustments to be made in the same manner described above in connection with
In another example, the teeth at the first interface 116 are spaced apart by 15 degrees and the teeth at the second interface 120 are spaced apart by 14.4 degrees. This enables adjustments to be made in the same manner described above in connection with
Certain embodiments have been described herein with a single spacer. However, any number of spacers can be used to form the humeral implant (e.g., two, three, four, or more). Further, the spacers in the humeral implant do not need to be identical. For example, some of the spacers can have the engagement features describe above while other spacers can have different engagement features (e.g., threadable engagements, slideable engagements, etc.). As another example, the spacer can include one or more springs, stoppers, and flange portions on pins. More details of alternative spacers are disclosed in U.S. Pat. No. 9,597,203, which is hereby incorporated by reference in its entirety.
The foregoing embodiments have described humeral implant applications. These embodiments can have other orthopedic applications, including implantation in other long bones or other long bone areas, e.g., the proximal or distal femur in hip or knee procedures, distal humerus in an elbow procedure, proximal or distal radius or ulna in elbow or wrist procedures, proximal or distal tibia or fibula in knee or ankle procedures. In each of these cases, the embodiments can enable gross or fine adjustment of a component, such as a first articular surface relative to an opposing component, such as a second native or prosthetic articular surface. These embodiments can be used in other joint procedures where the orientation of the components could benefit from gross or fine adjustment, such as in spinal body fusion or spinal motion preserving implants in spinal joints.
Terminology
Certain methods are described as sliding a first component relative to a second component. However, it should be understood that relative motion between first and second components can also include sliding the second component relative to the first component. For example, “sliding the intermediate portion in a transverse direction relative to a longitudinal axis of the metaphyseal portion” can also include “sliding the metaphyseal portion in a transverse direction relative to a longitudinal axis of the intermediate portion.”
“Implant” is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and includes, without limitation, temporary implants (e.g., for trialing) or permanent implants (also referred to herein as definitive implants) for any anatomy, including, but not limited to, shoulder replacements, knew replacements, femoral replacements, and hip replacements.
As used herein, the term “metaphyseal portion” refers to either a reverse metaphyseal portion or an anatomic metaphyseal portion unless otherwise specified.
As used herein, the relative terms “proximal” and “distal” shall be defined from the perspective of the humeral component. Thus, proximal refers to the direction of the metaphyseal portion and distal refers to the direction of the stem portion.
For expository purposes, the term “transverse” as used herein is defined as a direction generally perpendicular to the longitudinal axis of the assembly, unless otherwise specified.
Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments.
The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.
The terms “approximately,” “about,” “generally,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within less than 10% of the stated amount, as the context may dictate.
The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between” and the like includes the number recited. Numbers preceded by a term such as “about” or “approximately” include the recited numbers. For example, “about four” includes “four”
Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. For example, actions such as “distally moving a locking element” include “instructing distal movement of the locking element.”
Although certain embodiments and examples have been described herein, it will be understood by those skilled in the art that many aspects of the humeral assemblies shown and described in the present disclosure may be differently combined and/or modified to form still further embodiments or acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. A wide variety of designs and approaches are possible. No feature, structure, or step disclosed herein is essential or indispensable.
Some embodiments have been described in connection with the accompanying drawings. However, it should be understood that the figures are not drawn to scale. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, it will be recognized that any methods described herein may be practiced using any device suitable for performing the recited steps.
For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. Further, the actions of the disclosed processes and methods may be modified in any manner, including by reordering actions and/or inserting additional actions and/or deleting actions. It is intended, therefore, that the specification and examples be considered as illustrative only, with a true scope and spirit being indicated by the claims and their full scope of equivalents.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/024399 | 3/27/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62652421 | Apr 2018 | US |
