WO2010062379A1 - Bone fracture fixation screws, systems and methods of use - Google Patents

Abstract

A bone screw (372) and suture anchoring device, and associated method, for the fixation of fractured bones. The device includes a threaded shaft (377), a head (376) and a plurality of suture receiving holes (342, 344) in the shaft and head. The device may be inserted across the fracture of a bone so that the threads of the shaft (377) exert a compressive force upon the fractured bone segments in order to fixate them and allow them to heal. Sutures may then be threaded through the receiving holes (342, 344) in the device and also through holes drilled into the bone segments requiring fixation, then tightened and tied to provide additional fixation force to the bone segments. The combination of functions of bone screw and suture anchor in the same device and the method of threading the sutures minimize the amount of hardware needed to accomplish the fixation and reduce the invasiveness of the procedure.

Description

Bone Fracture Fixation Screws, Systems and Methods of Use by Kai Mazur, Stephen Gunther, Stephen R. McDanial, Heber Saravia

Cross Reference to Related Applications This application claims priority from a Unites States Provisional Application No.

61/117,901 filed on 25 November 2008 by Mazur et al. The entire contents of that application are incorporated by reference herein.

Technical Field The present invention relates to devices and methods for providing reinforcement of bones. More specifically, the present invention relates to devices and methods for providing reconstruction and reinforcement of fractured bones.

Background Art Bone fractures are a common medical condition of the population. Sports and work-related accidents account for a significant number of fractures among all age groups. The incidence of fracture in the general population increases with age as osteoporosis and osteoarthritis, common in the elderly, are a significant underlying cause of fracture as well. One current treatment method of bone fractures includes surgically resetting the fractured bone and then setting the bone containing body part in an external cast to immobilize the section of the body containing the fracture until the bone can mend. Casts however are uncomfortable for the wearer as they are heavy and hot and interfere with the wearing of clothes during the healing process. They also provide no internal fixation of the fracture for reinforcement purposes and rely exclusively on the immobilization of the body part to ensure that the fractured bone segments remain aligned during the healing process.

(External fixation is another technique employed to repair fractures. In this approach the fracture may be set and a rod or brace may traverse the fracture site external to the epidermis where the rod is attached to the bone with trans-dermal screws. This requires multiple incisions and fixation screws and presents the opportunity for multiple infection paths. Furthermore the external fixation is cosmetically intrusive, bulky and prone to painful inadvertent manipulation by bumping or brushing against objects, lntermedullary nails or rods are another technique which are particularly well suited for fractures of longer, slender bones where the fracture occurs somewhere near the midpoint of the bone. In this application a metal rod is placed inside a canal of a bone and fixed in place by means of integrated or ancillary anchoring mechanisms. The anchoring mechanisms attach from the inside of the canal to the compact or denser cortical bone situated at the outside surface of the bone as well as to the softer, cancellous bone located in the center of the bone. The rod can be left in place or subsequently removed after the fracture has healed. While useful in situations where the fracture is situated closer to the midpoint of long, slender bones, intermedullary rods are not optimally-suited for situations where the fracture is closer to the end of the bone, especially if the smaller segment of bone is also connected to a ligament. Bone screws by themselves have long been available as a means for repairing fractures and are particularly well suited for fractures which occur close to the end of longer, slender bones where the use of an IM rod may not be well suited. In such instances the fracture often results in a smaller segment of bone requiring fixation to the longitudinal axis of the longer, slender segment A screw can be inserted through the smaller segment and then threaded into the longitudinal axis of the longer segment. The threads and head of the screw provide compressive force along the longitudinal axis which serve to mend the fracture. Frequently this compressive, longitudinal force is not sufficient to promote rapid mending because the smaller segment of bone is often attached to ligaments which provide a torsional rotating and tipping force to that segment. This torsional force cannot be completely counteracted by the compressive force of the bone screw no matter how tightly it is threaded across the fracture, and as a consequence the fracture does not heal properly because of repeated disturbance of the fracture from the force applied by the ligament.

Suturing of small fractured segments has long been an alternative to the use of rods, nails and screws and is particularly well suited to situations where the fracture may not be completely transverse to the longitudinal access. Where sutures are used as a fixation technique, an anchor, often in the form of a short screw with a through-hole in the distal portion of the shaft, may be inserted in the bone on one side of the fracture. Additional anchors may be inserted on the other side of the fracture if there is sufficient mass of bone to support an anchor at a second location. The suture is then arrayed between the anchors and across the fracture to provide compressive force across the fracture and resistance to torsional rotating and tipping forces about the smaller bone segment. Although a proven technique, the use of the suture by itself does not afford the reinforcing strength across the fracture that the bone screw or the rod do. Furthermore, the suture method described also requires the creation of at least two anchor points which is not required when using just the bone screw approach.

The currently available approaches have room for improvement in various areas such as fixation strength, fixation stiffness, incision size reduction, ability to treat comminuted fractures, treating more end of shaft fractures and resistance to torsional 75 rotation and lifting forces in bone segments attached to ligaments.

Therefore what is needed is a device and method which does not require the use of large incisions, casts or bulky eternal fixation devices for approximation and immobilization of fractures, while providing sufficient lateral stiffness and compressive fracture fixation force. Furthermore the device must not suffer from the inability to 80 counter the disruptive torsional forces exerted by ligaments on the proximal segments of fractured bones that occurs where intermedullary rods or bone screws are used by themselves. What is needed is a device and method which combines the features of a bone screw and a suture to fixate bone fractures with lateral rigidity across the fracture, compressive force along the axis, and resistance to ligament-induced torsion on the 85 proximal fractured segment.

Disclosure of Invention

The present disclosure advantageously addresses one or more of the 90 aforementioned deficiencies in the field of bone fracture fixation by providing a bone screw and suture anchoring device, and associated method, for the fixation of fractured bones. The device includes a threaded shaft, a head and a plurality of suture receiving holes in the shaft and head. The device may be inserted across the fracture of a bone so that the threads of the shaft can exert a compressive force upon the fractured bone 95 segments in order to fixate them and allow them to heal. Sutures may then be threaded through the receiving holes in the device and also through holes drilled into the bone segments requiring fixation, then tightened and tied to provide additional fixation force to the bone segments. In addition to the compressive force exerted by the screw threads, the device and method provide longitudinal rigidity as well as resistance to rotational and

100 lifting forces in bone fragments that are subject to torsion from ligament attachments and other sources. The combination of functions of bone screw and suture anchor in the same device and the method of threading the sutures minimize the amount of hardware needed to accomplish the fixation and reduces the invasiveness of the procedure.

An embodiment of the present disclosure comprises a bone screw with a shaft,

105 with a threaded section and unthreaded shank, a distal tip and a proximal head. The head has a diameter greater than that of the shaft in order to capture the proximal bone fragment which the underside of the head contacts when advanced against the fragment. This puts the proximal fragment into compression with the opposing, main bone fragment by virtue of the force exerted on the main fragment by the threaded section of the screw

110 embedded in that fragment Suture receiving holes may be configured transversely through the unthreaded shank of the screw at a point below the head to allow for the threading of sutures through the screw. Additional suture receiving holes may be configured in the head along transverse and longitudinal axes, with those along the longitudinal axes being offset from the central axis of the screw. These receiving holes,

115 like those in the shank, may be used to receive sutures and wires which may be anchored at locations on the main fragment on the distal side of the fracture.

In another embodiment, the screw head has an inner section connected to the shaft with a socket in this inner section for receiving a driving tool to rotate the screw during insertion and removal. Surrounding this inner section of the head is an outer

120 section in the form of an annular ring with a plurality of through holes for receiving sutures and wire; these through-holes being oriented both parallel and perpendicular to the axis of the screw. The outer head is configured to rotate freely about the inner head without being capable of sliding passed the inner head along the longitudinal axis of the shaft. This configuration allows sutures to be threaded through the holes in the outer

125 head before seating of the screw head in the cortical bone. Because the outer head can rotate freely about the inner head, the sutures and wires threaded through the holes in the outer head do not become tangled or twisted as the screw is advanced to its final position.

In another embodiment the screw may include a self tapping and self threading

130 tip whereby a cutting feature is created by the fluting of a portion of the helical threads surrounding the tapered tip of the screw. This may allow the screw to be inserted in the bone without first drilling and tapping a receiving hole.

In yet another embodiment the screw may include a self countersinking head with cutting surfaces arrayed on the underside of the head that allow it to be self-countersunk

135 into the bone thereby eliminating the need to create a countersink cavity with a separate instrument before insertion of the screw. The screw may then sit flush or recessed in the surface of the bone upon full insertion.

The disclosure also includes a method for employing the device whereby the screw is inserted across the fracture along the longitudinal axis of the bone. This is

140 accomplished by approximating or setting the bone fragments and then either drilling a cavity through the fragments along which to insert the screw or allowing the screw to create its own cavity as it is advanced by relying on self-tapping features of the screw if such a features is present in a particular embodiment. Once the screw is completely or nearly emplaced sutures or wires may be threaded through the receiving holes in the

145 shank and head. A small through hole may be drilled laterally through the bone of the main bone fragment. The sutures threaded through the holes in the screw are then threaded through the lateral hole of the main bone fragment and drawn tight and tied. If desired the sutures may be configured in a cross pattern to provide additional stability and resistance to torsional forces on the proximal fragment. The screws and sutures 150 may be left in place permanently or may be removed once the fracture is healed.

A novel and non obvious feature of the device and associated method is its combination of cross fracture fixation with suture anchoring in a single piece of hardware. This allows a single device to provide rigid resistance to opposing transverse forces on

155 opposite sides of the fracture, with longitudinal compressive force across the fracture, and resistance to torsional forces at the end of the fractured bone segment. This combination of capabilities is achieved by the placement of suture receiving holes in the head and shank of the bone screw thereby allowing the screw to serve both as a fracture fixator and a suture anchor.

160 Another novel feature is the combination of transverse and longitudinal suture receiving holes in the same device.

Another novel feature is the freely rotating outer head, in the form or an annular ring, which surrounds the main, inner head and contains suture receiving holes. The rotating outer head has teeth on the underside to aid in maintaining a fixed orientation

165 once the underside of the outer head comes into contact with the bone and the inner head continues to be rotated by a driver for purpose of tightening or advancing the screw.

The device affords the user one or more of the following advantages. The

170 multitude of forces exerted by the device and associated method allows the user to fixate fractures with one piece of hardware where previously two or more might have been necessary. For example if an intermedullary rod where used in place of the screw and sutures were also required at least one suture anchor would need to be installed in one of the bone fragment in addition to the rod.

175 Another advantage is that the presence of both transverse and longitudinal suture receiving holes in the same device allows the user the flexibility to choose which orientation is best suited for the current application after partial or complete insertion of the device. This is useful because it is sometimes only after insertion that it becomes apparent which hole orientation is more desirable. In addition, a multitude of orientations

180 in one device reduces the number of different devices the user must have on hand during a procedure.

Another advantage is that the freely rotating outer head with suture receiving holes allows the sutures to be threaded through the device prior to insertion of the device in the patient without the concern that the sutures will become tangled or improperly

185 oriented during insertion when the screw must be rotated by a driving mechanism. It is therefore the purpose of this invention to fixate bone fractures by providing rigid lateral fixation, compressive longitudinal cross-fracture force and resistance to torsional rotation and lifting of proximal bone fracture segments.

190

The present invention will now be described more fully with reference to the accompanying drawings, which are intended to be read in conjunction with both this summary, the detailed description, and any preferred or particular embodiments specifically discussed or otherwise disclosed. This invention may, however, be embodied

195 in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of illustration only so that this disclosure will be thorough, and fully convey the full scope of the invention to those skilled in the art.

200 Brief Description of Drawings

FIG. 1 illustrates a side elevation of an embodiment of the device where the tip is modified to include a self tapping and threading feature.

FIG. 2 illustrates a bottom perspective of the device depicted in FIG. 1.

FIG. 3 illustrates a plan view of the device depicted in FIG. 1. 205 FIG. 4 illustrates a top perspective view of the device depicted in FIG. 1.

FIG. 5 illustrates a side elevation of an embodiment of the device where the tip has a blunt profile and suture through holes are located in the shaft and head.

FIG. 6 illustrates a plan view of the device of FIG. 5.

FIG. 7 illustrates a bottom plan view of the device FIG. 5.

210 FIG. 8 illustrates a side elevation of an alternate embodiment where axial bores and radial suture through holes intersect at the outer circumference of the head.

FIG. 9 illustrates a side perspective of the alternate embodiment of FIG. 8.

FIG. 10 illustrates a cross section of the head of the alternate embodiment of FIG. 8.

215 FIG. 11 illustrates a top perspective of an embodiment with freely rotating outer head section and the attached inner head with suture receiving holes in the in the outer head section.

FIG. 12 illustrates a bottom perspective of the alternate embodiment of FIG. 11.

FIG. 13 illustrates a cross section of the device illustrated in FIG. 11 along the 220 longitudinal axis.

FIG. 14 illustrates an exploded view of the head from the embodiment illustrated in FIG. 11 with rotating outer head separated from the inner, attached head. FIG. 15 illustrates a top perspective of an alternate embodiment of the device with a self countersinking head.

225 FIG. 16 illustrates a bottom perspective of an alternate embodiment of the device with a self countersinking head.

FIG. 17 illustrates a top plan view of the device depicted in FIG. 15.

FIG. 18 illustrates a bottom plan view of the device depicted in FIG. 15.

FIG. 19 illustrates an embodiment of the device and an associated method of 230 use in which the device is inserted into a bone and threaded with sutures that also run through a lateral hole in the bone.

FIG. 20 illustrates top perspective view of the device and associated method depicted in FIG. 19.

FIG. 21 illustrates top down view of the device and method illustrated in FIGS. 19 235 -20.

FIG. 22 illustrates an embodiment of the device and associated method of use where the device is inserted across multiple fractures.

FIG. 23 illustrates and embodiment of the device and associated method of use where the device is inserted across multiple fractures and a suture is threaded through 240 the head of the device and lateral through holes in the in two bone fragments.

FIG. 24 illustrates an alternate method of use where the screws are inserted through bone into a curved hub of an intermedullary rod.

245 Best Mode for Carrying out the Invention

To provide context for the invention, it may be useful to understand that bone is often described as a specialized connective tissue that serves three major anatomical functions. First, bone provides a mechanical function by providing structure and muscular attachment for movement Second, bone provides a metabolic function by

250 providing a reserve for calcium and phosphate. Finally, bone provides protective function by enclosing marrow and vital organs. Bones ca be categorized as long bones (e.g. radius, femur, tibia and humerous) and flat bones (e.g. skull, scapula and mandible). Each bone type has a different embryological template. Each bone type contains cortical and trabecular bone in varying proportions. The devices of this

255 invention can be adapted for use in any of the bones of the body as will be appreciated by those skilled in the art.

Cortical bone (compact) forms the shaft, or diaphysis, of long bones and the outer shell of flat bones. The cortical bone provides the main mechanical and protective function. The trabecular bone (cancellous) is found a the end of the long bones, or the

260 epiphysis, and inside the cortex of flat bones. The trabecular bone consists of a network of interconnecting trabecular plates and rods and is the major site of bone remodeling and resorption for mineral homeostasis and is typically less dense than cortical bone.

Once a bone is fractured, the bone segments are positioned in proximity to each other, called approximation, in a manner that enables woven bone to be laid down on the

265 surface of the fracture. This finely woven bone lacks the organized structure of either cortical (dense) or cancellous (spongy) bone. Where fracture fixation devices such as the screws described in this disclosure are used to repair the fracture, access to the surface of the bone fragments is accomplished through surgical techniques. The segment or fragment of bone on the side of the fracture through which the fixation device

270 is initially introduced is regarded as the proximal segment while the segment of bone on the opposing side of the fracture is regarded as the distal segment.

This description of anatomy and physiology is provided in order to facilitate an understanding of the invention. Persons of skill in the art will also appreciate that the scope and nature of the invention is not limited by the anatomy discussion provided. It

275 will be appreciated there can be variations in anatomical characteristics between bones which are not described herein.

Detailed Description

The present disclosure is directed to a bone fracture fixation screw and method

280 for repairing bone fractures. As depicted in FIGS. 1-2 an embodiment of the device 340 can comprise a shaft with a threaded section 350 and an unthreaded shank section 352, a tip 353, and a head 346. Suture and wire receiving holes may be arrayed in a variety of configurations in the head 346 and shank 352 to accommodate various techniques for threading and tying sutures. As shown in FIGS. 3-4 the head 346 further comprises a

285 socket 348 for receiving a driving tool for purposes of inserting and removing the device. The head 346 of the screw 340 can be configured in a plurality of shapes and equipped with cutting surfaces on the underside of the head to aid in countersinking the screw into the bone. Likewise, the tip 353 of the screw may be configured in a plurality of profiles and can be configured with a self tapping and threading feature 354 to aid in insertion.

290 These elements, which can be configured in a variety of combinations with each other, are described in greater detail in the following sections.

Shaft

As depicted in FIGS. 1-2 the shaft comprises a cylindrical column extending 295 between a tip 353 and a head 346 of the screw 340. It comprises a threaded section

350, which may extend the entire length of the shaft, and an unthreaded section 352, the shank, in the case where the threaded section extends only from the tip to some intermediate point along the shaft. The shaft may be configured in a plurality of lengths and diameters depending on the size of the bone the device is intended for and the

300 location of the fracture within the bone, with fractures further from the ends of the bone requiring longer screws. The threads may be configured in a variety of pitches and thread depths to accommodate bones of different hardness and may be further configured to have an outside diameter greater than, equal to or lesser than the shank of the shaft.

305 As depicted in FIGS. 5-7 the shaft may further comprise suture receiving holes

388 positioned to extend radially through the shank of the shaft at a point below the head 390 of the screw. These receiving holes 388 are designed to allow the passage of sutures and wires through the shaft so that they may be tensioned and tied to each other as part of the fracture repair system. The shaft-positioned suture receiving holes 388 are

310 especially useful where smaller screws with small heads are employed where there is not sufficient space in the head of the screw to accommodate suture receiving holes in the area around the receiving socket for the driver.

Tip

315 The tip 353 of the screw is located at the distal end of the shaft and may be configured with a blunt profile as in FIG. 5, or a pointed profile as in FIG.16, or an intermediate profile as in FIG. 1 where the tip 353 is partially conical but the end is nonetheless blunted. The tip 353 may also be configured with a self-tapping and self threading cutting element 354 as depicted in FIGS. 1,2. This element is formed by the

320 creation of a longitudinal quarter-section cut into the first several threads at the distal end of the shaft which exposes the cross section of the threads for cutting purposes.

Head

The head 346 is connected to the proximal end of the shaft and as depicted in

325 FIG. 3 and comprises a socket 348 for accepting a driving tool, and a plurality of suture receiving holes 342, 344 for threading sutures or wires. The suture receiving holes 344 may be arrayed axially and offset from the center axis, laterally and offset from the center axis 342, or as in FIGS. 8-10, radially and intersecting 396. The axial, lateral and radial holes may be configured singularly or in multiples.

330 In an alternate embodiment show in FIGS. 11-14 the head may comprise two parts, a fixed inner head 376 attached to the proximal end of the shaft, and freely rotating outer head 374 in the form of an annular ring that can rotate about the inner head 376 and can translate axially toward the tip 354 of the screw but cannot translate axially past the inner head 376. The inner head 376 further comprises a socket for receiving a driver 335 and an outside axial surface 380 that is angled so that the circumference of the top of the inner head 376 is greater than the circumference of the bottom of the inner head 376. The inside surface 389 of the outer head is sized and angled to mate with the sloping outside surface 380 of the inner head so that the inner head can rotate freely passed the outer head but not pass through the outer head. The outer head 376 may further include

340 a plurality of suture receiving holes 342, 344 oriented axially and laterally through the outer head for the purpose of receiving sutures and wires.

As depicted in FIGS. 15 - 18, the head 212 may also include one or more cutting surfaces 214 on the underside of the head to aid in creating a countersink in the bone so that the screw may not protrude above the surface of the bone after it is inserted. The

345 cutting surfaces 214 comprise conical surfaces 218 that form a 65 degree angle with the top of the head 212. These same features form a 50 degree included angle with each other. In other embodiments not shown, the conical surface 218 may form a 30, 45, 60 or 75 degree with the top surface. In other embodiments, the angle may be between 0 and 90 degrees, inclusive. The cutting surfaces 218 may be ground, sheared, milled,

350 molded, cut or otherwise formed on the head 212 to create leading surfaces 220. Each leading surface 220 may form a compound angle with the longitudinal axis of the screw 210. The longitudinal component of the compound angle may be equivalent to the conical angle of head 212 (i.e. 65 degrees in the embodiment shown), as best seen in FIG 18. In the exemplary embodiment shown, the radial component of the compound

355 angle is about 30 degrees in that each leading surface 220 forms an angle α of about 30 degrees with a tangent line at the outer circumference of the head 212 when viewed axially, as shown in FIG. 18. In the embodiment shown, the wide section of each cutting surface 214 is 1/8 of the radius of the maximum circumference of the head 212. Although three cutting surfaces are shown, one, two, four, five, six or more may

360 alternatively be used. As will be apparent to those skilled in the art, alternative angles, dimensions, and features may be used to create the cutting surface for a self countersinking screw head.

In an embodiment depicted in FIG. 15, the device is intended to be self tapping 365 and self countersinking and thus comprises a threaded shaft, a pointed tip with self tapping element 216, a flat profile head 212 which further comprises a socket 206 and a plurality of cutting surfaces 218. This embodiment contains no suture receiving holes in either the shaft or the head.

An alternate embodiment is depicted in FIG. 1 , where the device 340 includes a 370 shaft with a threaded section 350 and an unthreaded shank section 352, a partially pointed tip with self threading cutting surface 354, a head 346 with laterally offset suture receiving holes 342, and axial wire receiving holes 344. The head 346 further comprises a socket for receiving a driving tool.

Referring now to FIGS. 11 -14 another embodiment of the present invention will

375 be described. In. this embodiment a screw 372 similar in construction to screw 340 described above is provided. Like screw 340, screw 372 includes two suture receiving holes 342 formed laterally through the head and two wire holes 344 formed axially through the screw head as described above. However, unlike screw 340, screw 372 is provided with a two-part head, a fixed inner head 376 attached to the proximal end of

380 the shaft, and freely rotating outer head in the form of an annular ring 374 that can rotate about the inner head 376 and can translate axially toward the tip 353 of the screw but cannot translate axially past the inner head 376. The inner head 376 further comprises a socket 348 for receiving a driver and an outside axial surface 380 that is angled so that the circumference of the top of the inner head 376 is greater than the circumference of

385 the bottom of the inner head 376. The inside surface 389 of the outer head 374 is sized and angled to mate with the sloping outside surface 380 of inner head 376 so that the inner head 376 can rotate freely passed the outer head 374 but not pass through the outer head 374. The outer head 374 may further include a plurality of suture and wire receiving holes 342, 344 oriented axially and laterally through the outer head 374 for the

390 purpose of receiving sutures and wires. In addition, the underside of the outer head 374 may also be provided with one or more spikes 382 for engaging with the bone so that its orientation with respect to the bone that it contacts remains fixed when pressure is applied to it by the advancing and rotating inner head 376. In this manner the two part head of screw 372 allows the screw to be loosened and tightened without changing the

395 orientation of the outer head 374. This in turn allows suture and wire receiving holes 342, 344 to be oriented as desired and remain independent from screw tightening or loosening.

In an exemplary embodiment, as depicted in FIG. 5, the device 384 includes a shaft with a threaded and an unthreaded shank section, and a tip 353 with a blunted

400 profile. The shaft is configured with six radial holes 388 at the top of the shank. The holes are arranged in two rows of three and extend transversely through the shank of the screw 384, with the holes of each row intersecting with each other at the center axis of the screw. The head 390 is configured with six axial holes 386 which are parallel to, offset from and equally spaced around a central longitudinal axis of the screw 384.

405 Holes 386 and 388 may each be configured to receive sutures or wires. The abundance of holes provided in screw 384 allows a surgeon to choose from a variety of hole orientations to suit each particular situation and/or allows many sutures and wires to be anchored to each screw 384 where fixation of multiple bone fragments may be required. Referring now to FIGS. 8 -10, another embodiment of the invention is shown.

410 Screw 392 is provided with four axial holes 394 and two radial holes 396. In this embodiment axial holes 394 are parallel to, offset from, and equally spaced around a central longitudinal axis of screw 391, and extend through head 398. Radial holes 396 extend transversely through the head 398, intersecting each other at the central axis of screw 392. Holes 386 and 388 may each be configured to receive sutures or wires.

415 Axial bores 400 may be provided at each circumferential exit point of radial holes 396 to provide clearance for sutures or wires extending through radial holes 396, so that the sutures or wires do not get pinched between the screw head and bone as the screw head 398 is tightened against the bone.

The device may be made from a variety of materials such as metal, composite,

420 plastic or amorphous materials which include, but are not limited to, steel, stainless steel, cobalt chromium plated steel, titanium, nickel titanium alloy (nitinol), superelastic alloy, and polymethylmethacrylate (PMMA). The device may also include other polymeric materials that are biocompatible and provide mechanical strength, that include polymeric material with ability to carry and deliver therapeutic agents, that include bioabsorbable

425 properties, as well as composite materials and composite materials of titanium and polyetheretherketone, composite materials of polymers and minerals, composite materials of polymers and glass fibers, composite materials of metal, polymer, and minerals.

Within the scope of the present invention, the device may further be coated with

430 proteins from synthetic or animal source, or include collagen coated structures, and radioactive or brachytherapy materials. Furthermore, the construction of the supporting framework or device may include radio-opaque markers or components that assist in the location during and after placement in the bone.

While exemplary embodiments of the present disclosure have been shown and

435 described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the disclosure. It should further be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the invention.

440

Industrial Applicability

Referring to FIGS. 19-21 a fixation arrangement according to aspects of the present disclosure is shown applied to a proximal fracture 314 in an ulna 316. Implantable bone screw 320 is provided with transverse holes 322, each formed through

445 the shank of the screw 320 just below the head 324. Screw 320 is driven through the proximal end 326 of the ulna 316 towards the distal bone segment, generally along the longitudinal axis of the bone. Screw 320 may bridge fracture 314 and engage with the main portion 328 of the ulna 316. A hole may first be prepared through the proximal bone portion 326 having a diameter larger than the maximum thread diameter of screw

450 320. With this arrangement, screw 320 may be slidably received through the screw hole in proximal bone segment 326 and threadably engage the main bone portion 328. When screw 320 is tightened, fracture 314 is approximated and screw 320 provides compressive fixation to keep proximal bone segment 326 from moving away from the main bone portion 328. This same result may be achieved be eliminating screw threads,

455 or providing a reduced screw shank diameter, in the portion of screw 320 that will be located within proximal bone segment 326. Alternatively, a smaller screw hole or no screw hole can be formed in proximal bone segment 326 prior to inserting screw 320. With this arrangement, fracture 314 may be approximated before screw 320 is installed across it, and screw 320 may threadably engage both bone portions 326 and 328.

460 Screw 320 may then provide compressive fixation to keep proximal bone segment 326 from moving away from main bone segment 328, and also provide tensile force to keep proximal bone segment 326 from moving closer to main bone segment 328. This latter arrangement may be desirable for fixating comminuted fractures.

Once screw 320 is at least partially implanted, a suture 330 may be placed

465 through one or both of the cross holes 322. As in the prior art, a hole 332 may be drilled laterally through the main bone portion 328, as shown, to provide an anchor point for the other end of suture 330. Suture 330 may be threaded in a figure-eight pattern and tightly tied to provide additional fixation and resistance to rotational and lifting torque. Screw 320 may be left with its head protruding from the bone 316 as shown, or it may be

470 tightened so that it rests against the bone 316, or is flush with or recessed in the bone surface depending on whether a countersink has been created, either by a cutting face on the underside of the screw head or a separate cutting implement. In some procedures sutures 330 may be omitted, with screw 320 providing all of the bone fixation. When no suture is used, the incision size may be reduced since no suture hole

475 through the distal bone segment need be provide. Accordingly, screw 320 may be provided with 0, 1, 2, 3, 4 or more cross holes for receiving sutures.

Referring to FIGS. 22, 23 another method of using the screw 340 is described. Much like the use of the screw 320 described above, screw 340 may be inserted in a generally axial direction through a long bone, such as an ulna 316. In the particular

480 situation depicted, the screw 340 traverses fractures 356 and 358. Thus, bone segments 360 and 362 are captured and secured to the main segment 364 of ulna 316. Bone segments 360 and 362 may be further secured by using sutures 330, shown in FIG. 23. In particular, transverse holes 366 and 368 may be formed in bone segment 362 and the main bone segment 364, respectively. As shown in FIG. 23, suture 330

485 may be secured through the hole 368 in the bone and one of the suture receiving holes 342 in the screw 340, in a manner similar to that described above. Another suture, omitted from illustration for clarity, may be secured through the hole 366 in the bone and through the same or other suture receiving holes 342 in the screw 340. To fixate a smaller bone segment 370 caused by fracture 371, that in this example is not captured

490 by screw 340, a rigid wire 308 may be inserted through one or both of the wire receiving holes 344 and into the bone segment 370, as shown in FIG 23. In this exemplary arrangement, screw 340, suture 330 and rigid wire 308 cooperate to fully fixate the comminuted fracture.

In another method of use the screws 206 are inserted through the straight or

495 curved hub 112 of a deployed intermedullary rod 100 for the purpose of fixing the position of the rod 100 in the bone. This method is shown in FIG. 24. Here, the fractured bone is approximated and the intermedullary fixator positioned across the fracture. Lateral holes are then drilled through the bone so as to intersect with preexisting holes in the hub 112 of the rod 100 that have been positioned so as to receive

500 the fixating screws 206. The fixating screws of the present disclosure are then inserted through the bone holes and the receiving holes in the hub of the rod. The cutting surfaces on the underside of the head serve to create a countersink cavity in the surface of the bone so that the screw may be positioned flush or recessed in the bone. The cutting surfaces may also seat into the hub 112 of the rod 100 thereby creating a locking

505 interface between the screw and the hub so that the screw does not inadvertently loosen with time.

While exemplary methods of use of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such methods are provided by way of example only and that other methods of employment are also

510 contemplated by this disclosure.

515

Claims

520 ClaimsWhat is claimed is:

1. A bone screw (340), comprising: 525 a. a shaft (351); b. a tip (353) at the distal end of the shaft (351); b. a threaded section (350) running from the tip (353) to a point along the shaft (351); c. an unthreaded section (352) extending along the shaft (351) from the proximal 530 end of the threaded section (350), said unthreaded section (352) having a plurality of radial through holes (388) for receiving sutures; and, d. a head (346) positioned at the proximal end of the unthreaded section of the shaft (352) comprising a socket (348) for receiving driving tools to rotate the screw and a plurality of through-holes (386) in the head (346) for receiving sutures and wires.

535

2. A device as in claim 1 wherein the tip (353) further comprises a cutting device (354) to aid in tapping and threading the screw hole.

3. A device as in claim 2 wherein the head (212) further comprises a plurality of cutting 540 faces (218) on the underside of the head (212) to cut a cavity as the head is rotated into the bone thereby allowing the screw to be self countersinking.

4. A device as in claim 2 wherein the through-holes (396) in the head are arrayed radially.

545

5. A device as in claim 2 wherein a plurality of the through-holes (342) in the head are arrayed laterally, and offset from the central axis.

6. A device as in claim 5 wherein a plurality of the through-holes (344) in the head (346) 550 are arrayed parallel to the axis of the screw.

7. A bone screw (372) comprising: a. a shaft for spanning a bone fracture and providing compressive force between fractured bone segments comprising:

555 i. a threaded section (377) of the shaft; and, ii. an unthreaded section (378) of the shaft; b. a tip (353) at the distal end of the shaft; and, c. a head at the proximal end, comprising: i. an inner section (376) connected to the shaft;

560 ii. a socket in the inner section for receiving a driving tool to rotate the device during insertion; ii. an outer section (374), surrounding the inner section (376), with a plurality of through-holes (342, 344) for receiving sutures and wires, said outer section (374) being configured to rotate freely about the inner section (376). 565

8. A device as in claim 7 wherein the tip (353) comprises a cutting device (354) to aid in tapping and threading the screw hole.

9. A device as in claim 8 wherein a plurality of the through-holes (344) in the outer 570 section of the head (374) are arrayed parallel to the axis of the screw (372).

10. A device as in claim 9 wherein a plurality of the through-holes (342) in the outer section (374) are arrayed laterally and offset from the axis of the screw (372).

575 11. A device as in claim 10 wherein the outer section of the head (374) has spikes (382) on the underside to prevent it from rotating once it is in pressured contact with bone.

12. A method for repairing fractured bones comprising: a. accessing the fractured bone through an opening in the skin, 580 b. approximating the bone segments in the correct position; b. inserting a bone screw with suture receiving holes from the proximal end of the bone across the fractures and along the longitudinal axis of the bone; c. drilling a lateral through-hole in the bone on the distal side of the fracture; d. threading at least one suture through the suture receiving holes of the screw 585 and the lateral through hole of the bone fragment; e. tightening the screw to the desired degree of compression; and, f. tying the sutures in a manner to provide additional resistance to rotation and lifting of the proximal bone segment.

590 13. A method as in claim 12 wherein the inserting step comprises: a. drilling a hole through the bone to access the intermedullary canal; b. advancing a threaded bone screw into the canal; and, c. seating the screw so that the head protrudes from the surface of the proximal bone segment. 595

14. A method as in claim 12 wherein the inserting step comprises: a. advancing a screw with self-tapping and threading tip into the bone without first drilling a hole into the intermedullary canal; b. creating a countersink for the screw head by cutting into the bone with the 600 cutting faces on the underside of the screw head; and, c. seating the screw in the bone with the head recessed below the surface of the bone.

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