HK1243303B - An intramedullary fixation apparatus and system for use in hip and femur fracture surgery - Google Patents

Description

Intramedullary fixation devices and systems for use in hip and femoral fracture surgery

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Non-Provisional Application No. 14/735,068, filed on June 9, 2015, in the U.S. Patent and Trademark Office.

Statement Regarding Federal Funding of Research and Development

not applicable

Microfilm accessories

not applicable

Technical Field

At least some embodiments disclosed herein relate generally to the field of orthopedic implant devices and systems for bone and joint surgery, and more particularly to intramedullary fixation devices and systems for certain types of fractures, including but not limited to hip and femoral fractures.

Background Art

Open reduction and internal fixation (ORIF) is an orthopedic procedure used to repair a broken bone. It is a two-part procedure. First, the broken bone is reduced or put back into place. Next, an internal fixation device is placed on or in the bone, or both, to hold the broken bones together, usually using screws, plates, rods, pins, or nails. Dynamic hip screws and gamma nails are two currently accepted fixation devices to treat unstable intertrochanteric and subtrochanteric fractures, which are common in older patients with osteoporosis but can be challenging and difficult to fix.

In the 1980s, perhaps the most common fixation method employed was the dynamic hip screw. Typically, a dynamic hip screw has three components: a dynamic compression screw (inserted into the femoral neck), a side plate, and multiple cortical screws (fixed to either the proximal or distal side of the femoral shaft, or both). The concept behind this design is to allow the femoral head component to move along a single plane—that is, the dynamic hip screw allows for controlled dynamic sliding of the femoral head component along the bone anatomy—and, because bone responds to dynamic stresses, the native femur can remodel and heal properly by compressing the fracture line. However, a disadvantage of this technique is that the plate is transverse to the weight-bearing line of the hip, so any defect in the medial femoral cortex (whether due to poor reduction, comminution, or migration) means that varus stresses will be applied to the fixation device with each weight-bearing step, which can lead to screw dislodgement from the femoral head, failure of the nail-plate joint, or dislodgement of the screws securing the plate to the bone.

The intramedullary Zickel nail addresses some of the above issues, but insertion has proven technically difficult even for experienced surgeons and presents its own challenges, one of which is the increased likelihood of fracture at the base of the greater trochanter.

The Gamma Nail is also an intramedullary fixation device design developed for semi-closed insertion. The Gamma Nail has three main components: an intramedullary rod (nail), which passes downward through the medullary cavity of the upper shaft of the femur; a compression screw, which passes through a hole in the proximal portion of the intramedullary rod and from there into the femoral head; and a positioning screw, which is used to prevent the main screw from rotating. The placement of the Gamma Nail itself is slightly difficult, and biomechanical experiments have shown that although the sliding ability of the compression screw is maintained in the Gamma Nail, it is still reduced compared to the sliding ability of the dynamic hip screw. This is a particular problem for robust or obese patients because it is difficult to gain access to the trochanter and to find the optimal entry point for introducing the compression screw. In addition, accidental fractures and over-penetration caused by the compression screw are not uncommon for the Gamma Nail, and the optimal level of compression of the fractured bone cannot always be achieved during surgery.

Other intramedullary fixation devices and systems have also emulated the Gamma Nail. For example, one relevant to the present application is disclosed in International Application Publication No. WO 02/098330 A2 (December 12, 2012) by HOFFMAN S.R.L. HOFFMAN S.R.L. discloses a device for proximally locking an intramedullary nail, in which a self-tapping transcervical longitudinal element (serving as a compression screw element) is housed within a "bell" (serving as a sheath) with one end tapered. A pin integrally extends from the inner surface of the bell (it is unclear whether there is a transverse hole in the bell to receive the pin, as the specification does not mention such a hole). The pin engages a slit in the outer surface of the self-tapping transcervical longitudinal element, preventing rotation of the longitudinal element within the bell but allowing translation of the compression screw element. The structure formed by the compression screw element and bell passes through the intramedullary nail and is locked relative to the intramedullary nail by a set screw, much like the compression screw in the Gamma Nail and similar devices and systems. This design, like the Gamma nail and other intramedullary nailing devices and systems known in the art, does not have a mechanism to prevent the compression screw from over-penetrating the femoral neck and femoral head, and achieving optimal compression is challenging because the structure formed by the compression screw and bell is fixed relative to the intramedullary nail.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of non-limiting examples in the accompanying figures in which like references indicate like elements.

1 is a perspective view of an intramedullary nail, a dynamic compression screw structure consisting of a longitudinal sheath and a compression screw, and a surgical screw as a fixation device;

FIG2 is a cross-sectional view of a dynamic compression screw structure with the compression screw fully inserted into the longitudinal sheath, illustrating a dynamic passageway for introducing an intramedullary nail through the dynamic compression screw structure;

FIG3 is a perspective view of a femur with the femoral head and neck reamed to receive a dynamic compression screw structure and with the longitudinal sheath in position ready for insertion;

FIG4 is a perspective view of a femur with a longitudinal sheath of a dynamic compression screw structure inserted into the femur and the compression screw of the dynamic compression screw structure positioned to be inserted into the sheath and thereby into the femoral neck and femoral head;

FIG5 is a perspective view of a femur that has been reamed for placement of an intramedullary nail through a dynamic compression screw construct via a dynamic passage created by aligning the upper and lower holes of a longitudinal sheath with the slits in the compression screw;

FIG6 is a perspective view of a femur and a surgical screw having an intramedullary nail inserted into the femur through a dynamic compression screw structure, the surgical screw being in a position ready for distal installation as a fixation device for securing the intramedullary nail in position relative to the femur;

7 is a perspective view of a femur into which an intramedullary nail has been inserted through a dynamic compression screw structure and into which a surgical screw has been inserted distally through a side hole of the intramedullary nail;

8 is a cross-sectional view of the intramedullary nail inserted through the dynamic compression screw construct into the medullary diaphysis of the femur showing the outer lip of the compression screw engaging the inner lip of the longitudinal sheath and the outer flange of the longitudinal sheath engaging the lateral cortex of the femur.

DETAILED DESCRIPTION

The following description and accompanying drawings are illustrative and should not be construed as restrictive. Numerous specific details are described to provide a thorough understanding. However, in some cases, well-known or conventional details are not described to avoid obscuring the description. References to "one embodiment" or "an embodiment" in this disclosure do not necessarily refer to the same embodiment, but may refer to at least one embodiment.

Throughout this specification, the phrase "one embodiment" or "an embodiment" indicates that a particular feature, structure, or characteristic described for that embodiment is included in at least one embodiment of the present disclosure. The appearance of the phrase "in one embodiment" or a substantially similar phrase in multiple places throughout this specification does not necessarily refer to the same embodiment, nor does it indicate that additional or alternative embodiments are exclusive of other embodiments. Furthermore, various features are described that are exhibited by some embodiments but not by others. Similarly, various requirements are described that are specific to some embodiments but not to others.

As shown in FIG1 , an embodiment of the system of the present invention includes: an intramedullary nail (intramedullary rod) 101; a dynamic compression screw structure 102, which includes a longitudinal sheath 103, the longitudinal sheath being open at a distal end 116 and a proximal end 117 and having an upper hole 109 and a lower hole 110; the dynamic compression screw structure further includes a compression screw 104 having a longitudinal slit and configured to be inserted into the proximal end of the longitudinal sheath; and may also have some fixation devices known in the art, such as surgical screws, bolts, or cable fixation devices, configured to maintain the intramedullary nail 101 in an appropriate position relative to the bone. By way of illustration and not limitation, in one embodiment, the intramedullary nail 101 may have one or more side holes 105 extending through the intramedullary nail proximally or distally, or both proximally and distally, relative to the long bone, each side hole 105 being configured to receive one or more surgical screws 106 configured to penetrate or pass through the intramedullary nail 101. As known in the art, intramedullary nail 101 can have solid, semi-solid or hollow core, can be curved to adapt to the anterior curvature of patient's femur, and can have length and proximal diameter and distal diameter that vary depending on specific patient.Particularly, the distal end 107 of intramedullary nail 101 tapers so that insertion, and intramedullary nail 101 can be configured to receive guide device or similar instrument currently known in the art at its proximal end 108 place.

In one embodiment, the longitudinal sheath 103 of the dynamic compression screw structure 102 is open at the distal end 116 and the proximal end 117 and has an upper hole 109 and a lower hole 110, which together are configured to receive the intramedullary nail 101 and allow at least a portion of the intramedullary nail 101 to pass laterally through the longitudinal sheath 103. In one embodiment, the distal end (insertion end) 116 of the longitudinal sheath 103 can be tapered, and its proximal end 117 can have an outer flange 118, and the longitudinal sheath can have an inner lip 119. The outer flange 118 can be configured to ensure that the longitudinal sheath 103 is not inserted beyond the lateral cortex of the femur. In one embodiment, the longitudinal sheath 103 can be pressed or screwed into the bone through a hole or passage that has been reamed in the bone.

In one embodiment, a self-tapping thread 111 may be employed at the distal end (insertion end) of the compression screw 104. In one embodiment, a drive portion 112 may be provided at the proximal end of the compression screw 104. The drive portion 112 may include some form of internal thread 113 or other fixing portion configured to receive a self-gripping screwdriver or similar tool currently known in the art. In one embodiment, the compression screw 104 may have a longitudinal slit 114 through the shank 115, which is configured to receive the intramedullary nail 101 and allow at least a portion of the intramedullary nail to pass through the compression screw 104. In one embodiment, the compression screw 104 may have an outer lip 120 at the proximal end, which is configured to engage the inner lip 119 of the longitudinal sheath 103 to prevent the compression screw 104 from further penetrating the bone.

2 , in one embodiment, a compression screw 104 can be inserted into the proximal end of the longitudinal sheath 103, and at least a portion of the intramedullary nail 101 passes through a dynamic pathway formed by alignment of the upper and lower holes 109, 110 of the longitudinal sheath 103 with the longitudinal slit 114 in the shank 115 of the inserted compression screw 104, and thereby into the medullary diaphysis of the femur, the dynamic pathway being configured to allow for postoperative movement of the compression screw relative to the intramedullary nail 101. This dynamic compression screw structure 102 or similar structures can be configured to allow for dynamic adjustment of the three-dimensional position, i.e., longitudinal, transverse, and normal (i.e., vertical) position of the compression screw 104 relative to the intramedullary nail 101, and thus, respectively, relative to the femoral shaft, femoral neck, and femoral head, thereby allowing for further compression of the fractured bone when the patient begins to bear weight on the joint after surgery.

An embodiment may be constructed from various stainless steels, titanium, titanium alloys, biodegradable materials, and other suitable materials known in the art, alone or in combination.

On the fracture operating table, after patient's proximal femur fracture is reset (if necessary) and after fluoroscope or similar guiding device or system are positioned on the proximal femur of fracture, can horizontally mark a small incision (usually less than 1 inch) on the fracture proximal femur, and can under the condition of reaming or not reaming, intramedullary nail 101 (can be Steinmann pin) is inserted into the degree of depth that is applicable to patient's anatomical structure in femoral neck or femoral head, and in fracture proximal femoral head, centered and slightly backward.Then, can place intramedullary nail 101 by means of guiding device or system, so that guarantee that intramedullary nail 101 becomes appropriate angle with respect to fracture proximal femur shaft.Then, can determine that compression screw 104 will be inserted into the required degree of depth in femoral neck and femoral head.

As shown in Figures 3 and 4, the neck 301 of the femur 303 and the bone 302 can then be reamed in a two-step process. First, a passage can be reamed at the desired angle from the lateral cortex of the fractured proximal femur to the center of the bone at the fractured proximal femur, according to the previously determined depth required for the compression screw. Second, a wider, shorter passage can be reamed at a roughly equal angle to accommodate the longitudinal sheath 103. Next, the longitudinal sheath 103 can be pressed or screwed into the bone until the outer flange of the sheath reaches the lateral cortex of the fractured proximal femur.

As shown in Figures 4 and 5, then, can the compression screw 104 (can be to be attached on the self-clamping screwdriver or similar device) be inserted through the longitudinal sheath 103 that has been embedded in the bone, and screw or otherwise be inserted in the femoral neck or the femoral head and enter in the longer narrower path that initially reamed out.As shown in Figure 6, the upper hole 109 in the longitudinal sheath 103 and lower hole 110 and the slit 114 in the compression screw 104 that has been inserted in the longitudinal sheath 103 can align, and the formed dynamic path that is used to introduce intramedullary nail 101 aligns with the medullary canal of femoral shaft.Then, can utilize fluoroscope or other guiding device or system to pass the bone structure and the medullary canal that intramedullary nail 101 is placed in femur by trochanterus of femur.As shown in Figure 6, Figure 7 and Figure 8, then, can utilize fluoroscope or other guiding device or system with one or more surgical screws 106 that intramedullary nail 101 is fixed to bone.

In the foregoing specification, the present disclosure has been described with reference to specific exemplary embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Claims (14)

1. An orthopedic fixation device, comprising: A dynamic compression screw structure, comprising a longitudinal sheath open at a distal end and a proximal end, the longitudinal sheath having an upper hole and a lower hole; and further comprising a compression screw having a longitudinal slit, the compression screw being configured to be inserted into the proximal end of the longitudinal sheath so as to form a dynamic passageway by alignment of the upper hole and the lower hole with the longitudinal slit, the dynamic passageway being configured to receive at least a portion of an intramedullary nail to be laterally passed through the dynamic passageway of the dynamic compression screw structure, the dynamic passageway being further configured to allow the compression screw to move relative to the intramedullary nail after implantation of the orthopedic fixation device; an intramedullary nail, at least a portion of which is configured to be passed laterally through a dynamic compression screw structure via a dynamic passage; and A fixation device is configured to maintain the intramedullary nail in position relative to the bone. 2 . The orthopedic fixation device according to claim 1 , wherein the distal end of the longitudinal sheath is tapered. The orthopedic fixation device according to claim 1 , wherein the longitudinal sheath has an outer flange at its proximal end. 4 . The orthopedic fixation device according to claim 1 , wherein the longitudinal sheath has an inner lip at a proximal end thereof, and the compression screw has an outer lip configured to engage the inner lip when the compression screw is inserted into the proximal end of the longitudinal sheath. 5 . The orthopedic fixation device according to claim 1 , wherein the compression screw has a driving portion, the driving portion has a fixing portion, and the fixing portion is configured to be received by a clamping screwdriver. The orthopedic fixation device according to claim 1 , wherein the compression screw has a self-tapping thread at a distal end thereof. 7. The orthopedic fixation device according to claim 1, wherein the intramedullary nail has one or more side holes passing through the intramedullary nail transversely. 8. The orthopedic fixation device according to claim 1, wherein the proximal end of the intramedullary nail is configured to receive a guide device. 9 . The orthopedic fixation device according to claim 1 , wherein a distal end of the intramedullary nail is tapered. 10. The orthopedic fixation device according to claim 1, wherein the intramedullary nail is solid. 11. The orthopedic fixation device according to claim 1, wherein the longitudinal sheath, the compression screw and the intramedullary nail are made of titanium. 12. The orthopedic fixation device according to claim 7, wherein the fixation means comprises one or more surgical screws, each surgical screw being configured to pass through one or more of the side holes. 13. The orthopedic fixation device of claim 12, wherein at least one of the surgical screws is self-tapping. 14. The orthopedic fixation device of claim 13, wherein at least one of the surgical screws is made of titanium.