Embodiments of the technology relate, in general, to surgical cut guide technology, and in particular, to a cutting guide system that allows for measured resection of a metatarsal bone in order to shorten the bone. Specifically, the process allows for a reproducible shortening without inducing angulation, and for an oblique diaphyseal osteotomy for improved union rates compared to the current standard procedure. Furthermore, the cutting guide design allows for compatibility with a plating system to prevent the need for re-drilling to apply plate fixation as well as set alignment for the reduction to the plate.
Metatarsal shortening osteotomies are largely achieved via two methods: a transverse diaphyseal shortening osteotomy or an oblique intraarticular shortening osteotomy about the metatarsophalangeal joint. The transverse shortening method spares the joint, but has frequent problems with non-unions due to the diaphyseal and transverse nature of the osteotomy. The oblique intraarticular shortening osteotomy (also referred to as a “Weil” osteotomy) has good union rates, but is technically challenging and can result in avascular necrosis of the metatarsal head, osteoarthritis, or plantar translation of the metatarsal head, which results in persistent pain. There is a need for an osteotomy system that avoids the complications of both.
Currently available solutions include a system that makes an oblique osteotomy through a specialized plate, as well as an external jig for measured resection for Weil osteotomies. The measured resection for Weil osteotomies still has the same drawbacks as a traditional Weil. The plate that allows for an oblique osteotomy has not been widely adopted for a number of reasons: the plate is rather large and bulky, the osteotomy is oblique but does not resect bone, rather relies on translation to shorten the bone. This does shorten the bone, but also translates the metatarsal laterally. Furthermore, it limits the amount of shortening due to the design. There is a need for a cut guide that allows for a stepwise procedure that eliminates the many variables present in freehand resections.
It is well described that oblique osteotomies in other areas of the body (specifically, the ulna for ulnar shortening osteotomies) have increased union rates compared to transverse. However, ulnar osteotomies are based on a plate, and therefore, an expensive implant. The system used for ulnar shortening osteotomies would not translate to metatarsal bone because of anatomic constraints on metatarsals. There is a desire for pre-planned measured resection that does not result in translation of the metatarsal, only longitudinal shortening. There is a need for low-profile plating to reduce risk of need for removal of implants in a second surgery. Lastly, there is a desire to avoid the complications of Weil osteotomies. Outcomes for the surgical treatment of arthritis or avascular necrosis of lesser metatarsophalangeal joints are quite poor, so there is a need to avoid a potentially unsalvageable complication.
The drawings and detailed description that follow are intended to be merely illustrative and are not intended to limit the scope of the invention as contemplated by the inventor. The detailed description of specific embodiments herein can be best understood when read in conjunction with the following drawings.
Various non-limiting embodiments of the present disclosure will now be described to provide an overall understanding of the principles of the structure, function, and use of the compositions, methods, and processes disclosed herein. One or more examples of these non-limiting embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that compositions and methods specifically described herein are non-limiting embodiments. The features illustrated or described in connection with one non-limiting embodiment may be combined with the features of other non-limiting embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” “some example embodiments,” “one example embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with any embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” “some example embodiments,” “one example embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The inventor conceived of a novel cut guide system that, for the purpose of illustration, is disclosed herein as applied in the context of an oblique diaphyseal osteotomy system for metatarsal bone (or simply “metatarsal”) shortening. While the disclosed applications of the inventor's osteotomy system satisfy a long-felt but unmet need in the art of osteotomies, it should be understood that the inventor's osteotomy system is not limited to being implemented in the precise manners set forth herein, but could be implemented in other manners without undue experimentation by those of ordinary skill in the art in light of this disclosure. Accordingly, the examples set forth herein should be understood as being illustrative only, and should not be treated as limiting.
Generally, the system described herein allows for reproducible measured resection, without risk to the metatarsophalangeal joints, with significantly reduced rates of nonunion. It allows for use of standard, low-profile plating that reduces re-operation risk and keeps implant costs down. The present osteotomy system avoids the complications of traditional methods: it spares the joint, while providing a larger surface area of bone for healing and thus reducing the rate of non-union. This removable guide for an oblique shortening osteotomy allows for perfect alignment of the plate for the plane of the osteotomy. In some embodiments, the cut guide allows for the guide placement to be reused for plate fixation.
The cut guide can be made using any process, such as injection molding or 3D printing. The cut guide may be constructed from a number of different materials. For instance, one or more polymers (e.g., a polyamide polymer like nylon), stainless steel, titanium alloy, cobalt chrome, or any of many metallic alloys approved for use in orthopedic cutting devices, or combinations thereof. The cut guide can be patient-specific or generalized. The cut guide can be a one-time-use product or it may be reusable. The cut guide may comprise a handle.
In some embodiments, the cut guide 100 comprises a central block 110 between one or more fixation flanges 115 on the ends of the central block to help center the cut guide on the bone 105. In some embodiments, the central block 110 is generally wider than the fixation flanges 115. In some embodiments, the cut guide 100 comprises two fixation flanges: one fixation flange 115 is located at the proximal (ankle) end 120 of the central block 110 and the other fixation flange 130 is located at the distal (toe) end 125 of the central block 110. In other embodiments, there may be more than two flanges, for instance, in addition to fixation flanges, positioning flanges may protrude off the medial side or lateral side 135 proximally and distally that go deep to the bone and help align the guide. The fixation flanges 115, 130 each comprise one or more holes 140 that are congruent with a plating system. The central block 110 comprises one or more slots 150. The central block 110 may be open on one side to allow for a wider range of saw blade use. Furthermore, the proximal flange 115 or distal flange 130 may only have one hole if preferred. It is possible that a fixation hole need be incorporated into the central block 110 based on the fixation method used.
The flanges may be designed to complement the specific anatomy or equipment used in a procedure. Multiple exemplary embodiments of cut guides are illustrated herein: a first embodiment (
The fixation flanges each comprise one or more holes that are congruent with a plating system. In some embodiments, one or more holes may comprise a receiving lip around the hole that is higher than or lower than the flange top surface to aid in guiding the fixation wire. For instance, as shown in
The fixation flange at the distal portion of the cut guide comprises one or more holes designed for fixation, such as olive wire fixation. The fixation flange at the proximal portion of the cut guide comprises one or more holes (which may be slightly offset to the center of the screw hole in the complementary plating system used to allow for compression). In some embodiments, the holes distally are spaced to allow for reuse of these holes for plate fixation after an osteotomy, and are fixated using olive wires of a diameter and length such that the holes do not need to be re-drilled. In the fifth embodiment this will be the case for both the proximal and distal holes, the proximal holes being slightly offset from the corresponding plate to allow for compression through the plate. The cut guide is designed such that a plate will fit right on after the resection has been completed without the need for re-drilling, etc. The design of the olive wires does not require an extra step of drilling the holes distally for plate fixation. Lastly, the distal holes may be divergent up to 20 degrees to the medial and lateral, to allow for wire fixation across the metatarsophalangeal joint and into the shaft of the metatarsal in instances where that is deemed appropriate.
The dimensions of the central block vary depending on the width, kerf, and length of the saw or burr. In some embodiments, for instance as shown in
As shown in
The central block 110 may comprise one to ten slots 150, more preferably two to five slots 150. In some embodiments, the central block comprises three slots 150. In some embodiments, the central block comprises four slots 150.
As shown in
In some embodiments, the cut guide length is from about 10 mm to about 100 mm, or about 45 mm. In some embodiments, the cut guide width W is about 10 mm. In some embodiments, the height and/or width of the cut guide varies along its length.
In an embodiment where there are four holes in a cut guide positioned from left to right (e.g., distal end, hole 1, hole 2, hole 3, hole 4, proximal end), hole 1 may be on a distal fixation flange, hole 2 may be between two slots on a central block, hole 3 may be on a proximal fixation flange, and hole 4 may be on the proximal fixation flange. In some embodiments, hole 3 comprises an about 1.87 mm diameter hole clearance to accommodate about 1.57 mm diameter olive wire. In some embodiments, hole 4 comprises an about 2 mm diameter hole clearance to accommodate about 1.6 mm diameter K-wires (Kirschner wires). In one embodiment, the distance from hole 3 to the proximal end is about 17.6 mm. In another embodiment, the distance from hole 3 to the proximal end is about 15.6 mm.
As shown in
In certain embodiments, cut guide design variation allows for positioning flanges that can be narrowed on to the bone medially and laterally to “auto-center” the cut guide. For example, as shown in
One method for use of an oblique diaphyseal osteotomy system for metatarsal shortening is illustrated in cross-sectional
Turning to
As shown in
In some embodiments, the plate 195 may have more or less holes 196 than the cut guide. For example,
By design, in some embodiments, proximal plate holes may be slightly offset from the proximal fixation flange/proximal pre-drilled holes such that metatarsal compression occurs when the screws are tightened down. Finally, wound closure and fluoroscopic assessment are performed per surgeon preference, completing the procedure.
The plate can vary based on the dimensions of the cut guide. The cut guide can vary depending on desired plate for fixation. The plate can be hybrid for locking and non-locking screw options. The plate can be stainless steel or a titanium alloy, or other material based on surgeon preference. The plate can include positioning flanges to center the proximal bone into the reduction armpit.
In some embodiments, the olive wires comprise longer and thicker threaded stems, and shorter drive wires so as not to block the saw angle for cutting. Alternatively, longer drive wires can be used and cut. In some embodiments, the cut guide can be designed to fit existing plating systems or new kits may be created which comprise complementary cut guides and plating systems.
While specific embodiments were illustrated and described herein, variations and modifications may be made by those skilled in the art without departing from the scope of this disclosure. The present disclosure is for purposes of illustration and not of limitation; it may take many forms other than those explicitly disclosed herein. As such, the claims below shall be read to include all obvious variations and modifications that may be within the spirit of this disclosure.
Number | Date | Country | |
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63224717 | Jul 2021 | US |