Joint stabilizing bone screw system

Abstract

A device comprising a cannulated screw configured to receive a spring into an interior volume of the cannulated screw, a first button sized to fit within the interior volume of the cannulated screw over the spring, and a second button. The device includes a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring.

Description

Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.JOINT STABILIZING BONE SCREW SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 777,421 entitled "JOINT STABILIZING BONE SCREW SYSTEM" and filed on March 25, 2025, the entire contents of which are hereby incorporated by reference.FIELD

[0002] The present invention generally relates to medical devices and, more specifically, to a bone screw system configured to provide improved joint stabilization.BACKGROUND

[0003] Patients with neuromuscular conditions often have subluxation of their hip joints.Conventionally, this condition is treated with invasive surgical procedures that cut and realign the proximal femur (osteotomy) and the acetabulum (hip socket) to try to increase joint stability. While these osseous re-alignments are often successful, re-dislocation is not uncommon because the procedure cannot fix the underlying issues related to abnormal muscle tone, pull, and incompetent soft tissues.

[0004] Due to the invasive and morbid nature of the current treatments, guided growth, or using a screw to modify the growth of the proximal femur has been utilized in an attempt at changing the shape of the proximal femur and improve stability. However, like the osteotomies, these guided growth procedures only address the skeletal elements of the instability.SUMMARY{08844365 / 1} -1-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.

[0005] This summary section is neither intended to be, nor should be, construed as being representative of the full extent and scope of the present disclosure. Additional benefits, features and embodiments of the present disclosure are set forth in the attached figures and in the description hereinbelow, and as described by the claims. Accordingly, it should be understood that this Summary section may not contain all of the aspects and embodiments claimed herein.

[0006] Additionally, the disclosure herein is not meant to be limiting or restrictive in any manner. Moreover, the present disclosure is intended to provide an understanding to those of ordinary skill in the art of one or more representative embodiments supporting the claims. Thus, it is important that the claims be regarded as having a scope including constructions of various features of the present disclosure insofar as they do not depart from the scope of the methods and apparatuses consistent with the present disclosure (including the originally filed claims). Moreover, the present disclosure is intended to encompass and include obvious improvements and modifications of the present disclosure.

[0007] The present invention generally relates to a device comprising a cannulated screw configured to receive a spring into an interior volume of the cannulated screw, a first button sized to fit within the interior volume of the cannulated screw over the spring, and a second button. The device includes a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[0009] In the drawings:

[0010] FIG. 1 is an exploded view of a joint stability implant device.{08844365 / 1} -2-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.

[0011] FIG. 2 is a diagram depicting a typical installation of the present joint stability implant device into a patient to provide joint stability.

[0012] FIGS. 3A-3D depicts a device comprising a sliding hip screw that may be utilized to inhibit growth of the femoral head.

[0013] FIG. 4 depicts a device comprising a sliding hip screw that may be utilized to inhibit growth of the femoral head that incorporates only a compression spring.

[0014] FIG. 5 depicts a device comprising a sliding hip screw.

[0015] FIGS. 6A-6D depicting an alternate embodiment of a device comprising a sliding hip screw.DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0016] The present invention generally relates to medical devices and, more specifically, to a bone screw system configured to provide improved joint stabilization.

[0017] Patients with neuromuscular conditions often have subluxation of their hip joints. This condition involves a partial (or total) dislocation of the hip joint in which the femoral head is displaced out of the hip socket. This condition is often treated via surgical procedures that involve cutting and realigning the proximal femur (osteotomy) and the acetabulum to try to increase joint stability. Although these surgeries can be successful, re-dislocation is not uncommon due to the factors (e.g., abnormal muscle tone, pull, and incompetent soft tissues) that resulted in the condition in the first place.

[0018] The present disclosure, therefore, provides an implantable device that provides proximal femoral guided growth through the use of a cannulated screw that provides augmented stability through an incorporated flexible and inelastic material. Using the device, hip rotation is controlled by a compressible chamber within the screw (e.g., containing a ball and spring). Under such a scenario, the screw of the device acts to guide growth, improving the shape of the proximal femur, while the device provides joint stability utilizing the flexible material traversing the hip joint. Consequently, the present device allows, but can be{08844365 / 1} -3-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.configured to constrain, rotatory motion of the hip joint through compression and relaxation of the incorporated spring.

[0019] The present implantable device, therefore, can provide growth control of the proximal femur, augment stability of the hip joint, and provide that stability while allowing some controlled hip motion. The device, therefore, may be utilized to repair coxofemoral luxation while maintaining sufficient degrees of freedom (e.g., allowing adequate flexion, extension, abduction, adduction, external rotation, internal rotation and circumduction).

[0020] In the present device, a flexible but generally inelastic material (e.g., a suture wire) passes through an entry port of a spherical button and then through the inner diameter of a compression spring that is housed / facilitated within the hollow body of the cannulated screw. The suture wire continues to pass through the remaining inner diameter of the cannulated screw body and out the femoral head where the wire then passes through the socket of the pelvis. The suture wire then passes through and double backs over another button returning through the screw, the spring, and the initial spherical button where a knot is tied to secure the mechanism and fix a loop in the suture wire. In this configuration, the compression spring allows for the maintaining the three degrees of freedom for a ball and socket joint. The medial button becomes fixated due to compressive forces from the suture wire and spring. As the joint undergoes abduction / adduction and external / internal rotation, the spring compresses within the body of the cannulated screw allowing for joint mobility rather than a single point fixation.

[0021] FIG. 1 is an exploded view of joint stability device 100. Device 100 is made up of button 102, which can be a spherical button referred to as the lateral button, a compression spring 104 (e.g., a stainless steel compression spring or nitinol spring), a hollow bodied cannulated screw 106 that is sized to receive and to house compression spring 104 in an interior volume of cannulated screw 106, and button 108 that may be shaped as a rectangular prism.

[0022] Although illustrated as having a spherical shape (i.e., button 102) or rectangular prism shape (i.e., button 108), it should be understood that button 102 and button 108 can have any shape, depending upon the requirements of the particular application of device 100. For example, each of button 102 and button 108 can generally have any shape that allows each{08844365 / 1} -4-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.button to provide an anchoring function, as described below, in which the button can receive (e.g., via holes formed within the buttons) or otherwise couple to inelastic material 110.

[0023] When device 100 is implanted, button 108 can operate as an anchoring mechanism within the pelvis. A loop of flexible but inelastic material 110 (e.g., heavy suture or metal cable) is threaded through device 100 and when forming a loop of fixed size (i.e., fixed length) operates to fix the maximum distance between button 102 and button 108.

[0024] In typical use cases, button 108 operates as a medial button that is placed on the inner surface of the pelvis and button 102 operates as a lateral button that is positioned inside hollow bodied cannulated screw 106 and against spring 104. With hollow bodied cannulated screw 106 placed within the femoral head, device 100 provides improved stability of soft tissue in the region. In particular, hollow bodied cannulated screw 106 is configured to house compression spring 104 but prevents spring 104 from passing through hollow bodied cannulated screw 106 (e.g., via a constriction or other blocking feature incorporated into a distal end of the cannula of hollow bodied cannulated screw 106). In this configuration, compression of compression spring 104 allows for rotation (internal and external) of the bone, that might not afforded by sutures that are fixed to the bone as in conventional stabilization approaches.

[0025] FIG. 2 is a diagram depicting aspects of a typical installation of device 100 into a patient to provide joint stability. The view of FIG. 2 is exploded to better illustrate the installation of device 100.

[0026] As shown, device 100 can be used to provide stability to a hip joint 200 that includes a femur 202 and pelvis 204 (only a portion of pelvis 204 is shown in FIG. 2). For installation, a first hole is formed through the head of femur 202 and a second hole is formed through the pelvis 204.

[0027] Hollow bodied cannulated screw 106 is then screwed into the hole of femur 202 and is retained therein. Button 108 is positioned over the hole formed in pelvis 204 (i.e., on the medial side of pelvis 204, as shown), on a surface of pelvis 204 opposite femur 202. Button 108 is dimensioned so that a longest dimension of button 108 (i.e., the length of button 108) is{08844365 / 1} -5-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.greater than the diameter of the hole and therefor, in the orientation shown in FIG. 2 cannot pass through the hole. In other embodiments, button 108 is dimensioned so that a smallest dimension of button 108 (i.e., the length of button 108) is greater than the diameter of the hole. For example, button 108 may be shaped as a sphere, where the diameter of the sphere is greater than a diameter of the hole.

[0028] Spring 104 is inserted into hollow bodied cannulated screw 106 and button 102 is positioned over compression spring 104 to form a cap on spring 104. Button 102 is sized to be able to enter the opening of hollow bodied cannulated screw 106 but cannot pass through the central opening of compression spring 104. Flexible but inelastic material 110 is threaded through all of the components of device 100 and is tied off to form an inelastic loop of material with button 102 and button 108 engaged at opposing ends of the loop of inelastic material 110.

[0029] With device 100 installed as depicted in FIG. 2, hollow bodied cannulated screw 106 provides proximal femoral guided growth. Additionally, the tension formed in flexible but inelastic material 110 by the position of button 102 and button 108 limits the ability of femur 202 to move away from pelvis 204, thereby retaining the head of femur 202 within the hip socket of pelvis 204. However, because in this arrangement, button 102 is constrained against the distal end of compression spring 104, with sufficient force applied to flexible but inelastic material 110, compression spring 104 will compress to some degree allowing for some additional (but constrained by compression spring 104) movement of femur 202 with respect to pelvis 204. When compression spring 104 is fully compressed, no further movement of the head of femur 202 away from pelvis 204 is possible.

[0030] Consequently, with device 100 installed as shown in FIG. 2, the patient retains some ability to move femur 202 in a rotational movement with respect to pelvis 204. The flexible but inelastic material 110 limits the amount by which the patient can perform hip abduction (i.e., increasing the distance between the femoral head and the pelvis) thereby mitigating the risk of subluxation. However, some abduction is permitted through button 102 applying a compressive force on spring 104 that, upon compression of compression spring 104, allows for additional movement of femur 202.{08844365 / 1} -6-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.

[0031] As depicted in FIGS. 1-2, in an embodiment, hollow bodied cannulated screw 106 is a relatively static component configured to be screwed or otherwise placed within the femoral head. In alternative embodiments of the present invention, hollow bodied cannulated screw 106 may be replaced a similarly configured screw members that are active and may thereby provide a femoral head growth modulation function or otherwise modulate a range of motion of femur 202 with respect to pelvis 204.

[0032] To illustrate, FIGS. 3A - 3D depicts device 300 comprising a sliding hip screw that may be utilized to control growth of the femoral head and that may be used in place of hollow bodied cannulated screw 106 of device 100 of FIG. 1. FIG. 3A depicts device 300 in which certain components are rendered transparently allowing internal components and features to be viewed. FIG. 3B is an exploded view of device 300 depicts all components of device 300 separated from one another. FIG. 30 is a perspective view of the exploded view of FIG. 3B allowing for views of additional features of device 300. FIG. 3D is a cross-sectional view of the exploded view of FIG. 3B taken at plane 3D-3D.

[0033] In the depicted embodiment, device 300 incorporates a spring configured to facilitate modulation of growth of the head of femur 202 by applying a compressive force across the growth plate thereof. At the same time a second spring is incorporated into device 300 to allow for some movement within the femoral head, as described below.

[0034] Device 300 includes anchor screw 302 and anchor screw 304. Sleeve component 306 is fixed to anchor screw 302. Shaft 308 is fixed to anchor screw 304. Shaft 308 is configured to fit within an opening formed by sleeve component 306.

[0035] The interior surface of the sleeve component 306 is non-uniform and includes a curved recessed portion 350 that runs along a length of the interior surface of sleeve component 306. Either side of curved recessed portion 350, the interior surface of the sleeve component 306 includes sloped, but planar, surfaces 352. These interior surface elements of sleeve component 306 are configured to receive similarly shaped surfaces on the outer surface of shaft 308. In particular, the outer surface of shaft 308 includes curved convex surface 354, which has the same curvature as curved recessed portion 350, and sloped, but planar, surfaces 356. Because{08844365 / 1} -7-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.the interior surface of sleeve component 306 and the exterior surface of shaft 308 as so configured, when shaft 308 is inserted into sleeve component 306, shaft 308 and sleeve component 306 cannot rotate with respect to one another. This allows the sleeve component 306 to be rotatably driven by application of a rotational force to shaft 308 when shaft 308 is inserted into sleeve component 306.

[0036] When device 300 is installed within the femoral header, a hole may first be formed into the femoral head. Then, device 300, which comprised both shaft 308 and sleeve component 306 to be driven into the hole by first inserting anchor screw 302 part-way into the hole and then applying a rotational force to shaft 308 to turn the combination of shaft 308 and sleeve component 306. That turn, when applied to anchor screw 302 screws device 300 into the femoral head. This action can be continued to screw device 300 into the femoral head until screw 304 engages with and is eventually screwed into the femoral head itself.

[0037] In one example installation of device 300, device 300 is installed across the growth plate of the femoral head such that anchor screw 302 is located on one side of the growth plate and screw 304 is located on another side of the growth plate. As such, when installed, device 300 passes through the growth plate of the femoral head. Shaft 308 can move within (i.e., slide into or slide out of, but not rotate within) sleeve component 306 so that the length of device 300 can be modified, such as when bone growth occurs at the growth plate.

[0038] In the depicted embodiment, sleeve component 306 includes a spring retention device 310 (e.g., a retention pin), which is fixed to sleeve component 306 and, thereby, anchor screw 302. Spring retention device 312 (e.g., a retention pin) is fixed to an end of shaft 308. Spring 314, which operates as an extension spring, is coupled at each end to spring retention device 310 and spring retention device 312. In this configuration, spring 314 prevents anchor screw 302 from moving away from anchor screw 304. When installed into a patient, such as with anchor screw 302 installed into a first bone feature, and anchor screw 304 installed into a second bone feature, spring 314 therefore applies a force configured to prevent those bone features from being moved apart from one another. As such, when device 300 is placed across the growth plate of the femoral head, for example, spring 314 is configured to generate a{08844365 / 1} -8-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.compressive force, thereby controlling growth at that growth plate and thereby modulating growth of the femoral head.

[0039] Additionally, device 300 includes spring 316 that is positioned within shaft 308. In this configuration, spring 316 operates as a compression spring (e.g., providing similar functionality to compression spring 104 of device 100). Specifically, as depicted in the cross-sectional view of FIG. 3D, the internal cannula of shaft 308 is constrained by retention feature 360 at the distal end of shaft 308 ( i.e ., opposite screw 304) that prevents spring 316 form passing through the distal end of the cannula of shaft 308.

[0040] As in device 100, described above, during use of device 300 in place of hollow bodied cannulated screw 106, a loop of flexible but inelastic material (not shown) (e.g., heavy suture or metal cable) can be threaded through device 300. In that configuration, where device 300 replaces hollow bodied cannulated screw 106 in device 100, spring 316 is constrained between retention feature 360 and button 102 thereby providing the functionality of compression spring 104 of device 100, as described above.

[0041] In other embodiments, of device 300, either spring 314 or spring 316 may be omitted to provide desired functionality of the device.

[0042] For example, FIG. 4 depicts device 400, which generally includes device 300 in which spring 314 is omitted. FIG. 4 depicts device 400 in which certain components are rendered transparently allowing internal components and features to be viewed. In this configuration, device 400 includes a sliding hip screw that may be utilized to control growth of the femoral head that incorporates only a compression spring. Device includes anchor screw 402 and anchor screw 404. Sleeve component 406 is fixed to anchor screw 402. Shaft 408 is fixed to anchor screw 404. Shaft 408 is configured to fit within an opening formed by sleeve component 406.

[0043] Device 400 includes spring 416 that is positioned between anchor screw 404 and end 418 of shaft 408. In this configuration, spring 416 operates as a compression spring (e.g., providing similar functionality to compression spring 104 of device 100). In this configuration, with device 400 installed across the growth plate of the femoral head (i.e., with anchor screw{08844365 / 1} -9-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.402 anchored on a first side of the growth plate and anchor screw 404 anchored on a second side of the growth plate) the femoral head is free to grow because, as growth occurs at the growth plate, anchor screw 402 and screw 404 are free to move apart from one another.

[0044] As in device 100, described above, during use of device 400, a loop of flexible but inelastic material (not shown) (e.g., heavy suture or metal cable) can be threaded through device 400. In that configuration, where device 400 replaces hollow bodied cannulated screw 106 in device 100, spring 416 provides the functionality of compression spring 104 of device 100, as described above.

[0045] FIG. 5 depicts device 500 comprising a sliding hip screw. Device 500 is similar to device 300 but omitting spring 316. Device includes anchor screw 502 and anchor screw 504. Sleeve component 506 is fixed to anchor screw 502. Shaft 508 is fixed to anchor screw 504. Shaft 508 is configured to fit within an opening formed by sleeve component 506.

[0046] Sleeve component 506 includes a spring retention device 510, which is fixed to sleeve component 506 and, thereby, anchor screw 502. Spring retention device 512 is fixed to an end of shaft 508. Spring 514, which operates as an extension spring is coupled at each end to spring retention device 510 and spring retention device 512. In this configuration, spring 514 prevents anchor screw 502 from moving away from anchor screw 504.

[0047] As in device 100, described above, during use of device 500, a loop of flexible but inelastic material (not shown) (e.g., heavy suture or metal cable) can be threaded through device 500.

[0048] FIGS. 6A and 6B depict device 600 comprising a sliding hip screw. FIG. 6A depicts a side view of device 600. FIG. 6B shows a cross-sectional view of device 600. Device 600 is similar to device 300 but omitting spring 316 and replacing spring 314 with a compression spring. Device includes anchor screw 602 and anchor screw 604. Sleeve component 606 is fixed to anchor screw 602. Shaft 608 is fixed to anchor screw 604. Shaft 608 is configured to fit within an opening formed by sleeve component 606.

[0049] Spring 614 is disposed within the interior volume of sleeve component 606, which operates a compression spring when compressed between an end 650 of the interior volume of{08844365 / 1} -10-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.sleeve component 606 and the end 652 of shaft 608. In this configuration, spring 614 prevents anchor screw 602 from moving towards anchor screw 504 and thereby provides a similar functionality as compression spring 104 of device 100, described above.

[0050] As in device 100, described above, during use of device 600, a loop of flexible but inelastic material (not shown) (e.g., heavy suture or metal cable) can be threaded through device 600.

[0051] In an embodiment of the present disclosure, a device comprises a cannulated screw configured to receive a spring into an interior volume of the cannulated screw, a first button sized to fit within the interior volume of the cannulated screw over the spring, and a second button. The device includes a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring.

[0052] In some aspects, the techniques described herein relate to a device, including: a spring; a cannulated screw configured to receive the spring into an interior volume of the cannulated screw; a first button sized to fit within the interior volume of the cannulated screw over the spring, wherein a smallest dimension of the first button is greater than an internal diameter of the spring; a second button; and a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring.

[0053] In some aspects, the techniques described herein relate to a device, wherein the flexible and inelastic material includes a suture wire.

[0054] In some aspects, the techniques described herein relate to a device, wherein the cannulated screw includes a sleeve component and a shaft component.

[0055] In some aspects, the techniques described herein relate to a device, wherein the shaft component, when inserted into the sleeve component, can slide into and out of the sleeve component but cannot rotate with respect to the sleeve component.

[0056] In some aspects, the techniques described herein relate to a device, wherein the spring includes nitinol.{08844365 / 1} -11-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.

[0057] In some aspects, the techniques described herein relate to an implant system, including: a cannulated screw configured to be inserted into a head of a femur, wherein the cannulated screw defines an interior volume of the cannulated screw; a spring configured to be disposed within the interior volume of the cannulated screw; a first button sized to fit within the interior volume of the cannulated screw over the spring, wherein a smallest dimension of the first button is greater than an internal diameter of the spring; a second button configured to be disposed at an inner surface of a pelvis; and a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring, wherein the implant system is configured to allow for abduction of the femur by compression of the spring.

[0058] In some aspects, the techniques described herein relate to an implant system, wherein the flexible and inelastic material is configured to determine a maximum distance between the first button and the second button.

[0059] In some aspects, the techniques described herein relate to an implant system, wherein the flexible and inelastic material determine a maximum abduction distance of the femur from the pelvis.

[0060] In some aspects, the techniques described herein relate to an implant system, wherein the cannulated screw, when installed into the femur, is configured to modulate a bone growth of the head of the femur.

[0061] In some aspects, the techniques described herein relate to an implant system, wherein the flexible and inelastic material includes a suture wire.

[0062] In some aspects, the techniques described herein relate to an implant system, wherein the spring includes nitinol.

[0063] In some aspects, the techniques described herein relate to a method, including: placing a cannulated screw into a head of a femur, wherein the cannulated screw defines an interior volume of the cannulated screw; inserting a spring into the interior volume of the cannulated screw; positioning a first button into the interior volume of the cannulated screw against the spring, wherein a smallest dimension of the first button is greater than an internal diameter of{08844365 / 1} -12-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.the spring; forming a hole in a pelvis; positioning a second button proximate an inner surface of the pelvis; and attached a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring and through the hole in the pelvis.

[0064] In some aspects, the techniques described herein relate to a method, wherein the flexible and inelastic material is configured to determine a maximum distance between the first button and the second button.

[0065] In some aspects, the techniques described herein relate to a method, wherein the flexible and inelastic material determine a maximum abduction distance of the femur from the pelvis.

[0066] In some aspects, the techniques described herein relate to a method, wherein the cannulated screw, when installed into the femur, is configured to modulate a bone growth of the head of the femur.

[0067] In some aspects, the techniques described herein relate to a method, wherein the flexible and inelastic material includes a suture wire.

[0068] In some aspects, the techniques described herein relate to a method, wherein the cannulated screw includes a sleeve component and a shaft component.

[0069] In some aspects, the techniques described herein relate to a method, wherein the shaft component, when inserted into the sleeve component, can slide into and out of the sleeve component but cannot rotate with respect to the sleeve component.

[0070] In some aspects, the techniques described herein relate to a method, wherein the cannulated screw is configured to modulate a growth of the head of the femur.

[0071] In some aspects, the techniques described herein relate to a method, wherein the spring includes nitinol.

[0072] The preceding detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments.

[0073] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as exemplary is not necessarily to be{08844365 / 1} -13-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, or detailed description.

[0074] The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in an embodiment of the subject matter. In addition, certain terminology may also be used herein for the purpose of reference only, and thus are not intended to be limiting, and the terms "first", "second" and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context.

[0075] As used herein, a "node" means any internal or external reference point, connection point, junction, signal line, conductive element, or the like, at which a given signal, logic level, voltage, data pattern, current, or quantity is present. Furthermore, two or more nodes may be realized by one physical element (and two or more signals can be multiplexed, modulated, or otherwise distinguished even though received or output at a common node).

[0076] The foregoing description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless expressly stated otherwise, "connected" means that one element is directly joined to (or directly communicates with) another element, and not necessarily mechanically. Likewise, unless expressly stated otherwise, "coupled" means that one element is directly or indirectly joined to (or directly or indirectly communicates with, electrically or otherwise) another element, and not necessarily mechanically. Thus, although the schematic shown in the figures depict one exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in an embodiment of the depicted subject matter.

[0077] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any{08844365 / 1} -14-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.{08844365 / 1} -15-

Claims

Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.CLAIMSWhat is claimed:

1. A device, comprising:a spring;a cannulated screw configured to receive the spring into an interior volume of the cannulated screw;a first button sized to fit within the interior volume of the cannulated screw over the spring, wherein a smallest dimension of the first button is greater than an internal diameter of the spring;a second button; anda flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring.

2. The device of claim 1, wherein the flexible and inelastic material includes a suture wire.

3. The device of claim 1, wherein the cannulated screw includes a sleeve component and a shaft component.

4. The device of claim 3, wherein the shaft component, when inserted into the sleeve component, can slide into and out of the sleeve component but cannot rotate with respect to the sleeve component.

5. The device of claim 1, wherein the spring includes nitinol.

6. An implant system, comprising:{08844365 / 1} -16-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.a cannulated screw configured to be inserted into a head of a femur, wherein the cannulated screw defines an interior volume of the cannulated screw;a spring configured to be disposed within the interior volume of the cannulated screw;a first button sized to fit within the interior volume of the cannulated screw over the spring, wherein a smallest dimension of the first button is greater than an internal diameter of the spring;a second button configured to be disposed at an inner surface of a pelvis; anda flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring, wherein the implant system is configured to allow for abduction of the femur by compression of the spring.

7. The implant system of claim 6, wherein the flexible and inelastic material is configured to determine a maximum distance between the first button and the second button.

8. The implant system of claim 7, wherein the flexible and inelastic material determine a maximum abduction distance of the femur from the pelvis.

9. The implant system of claim 6, wherein the cannulated screw, when installed into the femur, is configured to modulate a bone growth of the head of the femur.

10. The implant system of claim 6, wherein the flexible and inelastic material includes a suture wire.

11. The implant system of claim 6, wherein the spring includes nitinol.

12. A method, comprising:{08844365 / 1} -17-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.placing a cannulated screw into a head of a femur, wherein the cannulated screw defines an interior volume of the cannulated screw;inserting a spring into the interior volume of the cannulated screw;positioning a first button into the interior volume of the cannulated screw against the spring, wherein a smallest dimension of the first button is greater than an internal diameter of the spring;forming a hole in a pelvis;positioning a second button proximate an inner surface of the pelvis; andattached a flexible and inelastic material attached to the first button and the second button, wherein the flexible and inelastic material is threaded through the interior volume of the cannulated screw and the spring and through the hole in the pelvis.

13. The method of claim 12, wherein the flexible and inelastic material is configured to determine a maximum distance between the first button and the second button.

14. The method of claim 13, wherein the flexible and inelastic material determine a maximum abduction distance of the femur from the pelvis.

15. The method of claim 12, wherein the cannulated screw, when installed into the femur, is configured to modulate a bone growth of the head of the femur.

16. The method of claim 12, wherein the flexible and inelastic material includes a suture wire.

17. The method of claim 12, wherein the cannulated screw includes a sleeve component and a shaft component.{08844365 / 1} -18-Patent Application Atty. Docket No. 12558.0011.002 Phoenix Children 's Hospital, Inc.

18. The method of claim 17, wherein the shaft component, when inserted into the sleeve component, can slide into and out of the sleeve component but cannot rotate with respect to the sleeve component.

19. The method of claim 12, wherein the cannulated screw is configured to modulate a growth of the head of the femur.

20. The method of claim 12, wherein the spring includes nitinol.{08844365 / 1} -19-

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