Orthopedic fixation system including plate element with threaded holes having divergent axes

[0001] This application is a continuation-in-part of U.S. Ser. No. 10/315,787, filed Dec. 10, 2002, which is a continuation-in-part of U.S. Ser. No. 10/159,611, filed May 30, 2002, which is a continuation-in-part of U.S. Ser. No. 09/735,228, filed Dec. 12, 2000 and now issued as U.S. Pat. No. 6,440,135, which is a continuation-in-part of U.S. Ser. No. 09/524,058, filed Mar. 13, 2000 and now issued as U.S. Pat. No. 6,364,882, and U.S. Ser. No. 09/495,854, filed Feb. 1, 2000 and now issued as U.S. Pat. No. 6,358,250, all of which are hereby incorporated by reference herein in their entireties.

[0002] 1. Field of the Invention

[0003] This invention relates broadly to surgical devices. More particularly, this invention relates to a bone fixation system including a plate element and an arrangement of pegs fixed relative to the plate element.

[0004] 2. State of the Art

[0005] Referring to FIG. 1, a Colles' fracture is a fracture resulting from compressive forces being placed on the distal radius 10, and which causes backward displacement of the distal fragment 12 and radial deviation of the hand at the wrist 14. Often, a Colles' fracture will result in multiple bone fragments 16, 18, 20 which are movable and out of alignment relative to each other. If not properly treated, such fractures result in permanent wrist deformity. It is therefore important to align the fracture and fixate the bones relative to each other so that proper healing may occur.

[0006] Alignment and fixation are typically performed by one of several methods: casting, external fixation, interosseous wiring, and plating. Casting is non-invasive, but may not be able to maintain alignment of the fracture where many bone fragments exist. Therefore, as an alternative, external fixators may be used. External fixators utilize a method known as ligamentotaxis, which provides distraction forces across the joint and permits the fracture to be aligned based upon the tension placed on the surrounding ligaments. However, while external fixators can maintain the position of the wrist bones, it may nevertheless be difficult in certain fractures to first provide the bones in proper alignment. In addition, external fixators are often not suitable for fractures resulting in multiple bone fragments. Interosseous wiring is an invasive procedure whereby screws are positioned into the various fragments and the screws are then wired together as bracing. This is a difficult and time consuming procedure. Moreover, unless the bracing is quite complex, the fracture may not be properly stabilized. Plating utilizes a stabilizing metal plate typically against the dorsal side of the bones, and a set of parallel pins extending from the plate into holes drilled in the bone fragments to provide stabilized fixation of the fragments. However, the currently available plate systems fail to provide desirable alignment and stabilization. Likewise, other fractures at the ends of other long bones suffer from similar problems.

[0007] It is therefore an object of the invention to provide an improved fixation and alignment system for fractures at the end of long bones and which can specifically be used to treat fractures at the end of long bones.

[0008] It is another object of the invention to provide a fixation system which desirably aligns and stabilizes multiple bone fragments in a fracture to permit proper healing.

[0009] In accord with these objects, which will be discussed in detail below, a fixation system is provided which generally includes a plate intended to be positioned against the bone, a plurality of bone screws for securing the plate along a non-fractured portion of the bone, and a plurality of pegs (fasteners having threaded heads and threaded or non-threaded shafts) which extend from the plate and into bone fragments of the fracture.

[0010] According to one embodiment, the plate is generally a T-shaped plate defining an elongate shaft portion, a head portion angled relative to the shaft portion, a first side which is intended to contact the bone, and a second side opposite the first side. The shaft portion includes a plurality of countersunk screw holes for the extension of the bone screws therethrough. The head portion includes a plurality of threaded peg holes for receiving the pegs therethrough. According to a first embodiment, the peg holes are preferably arranged along a curve. According to a second embodiment, the peg holes are preferably linearly arranged. In either embodiment, the peg holes are preferably positioned increasingly distal in a medial to lateral direction along the second side. According to a preferred aspect of the invention, axes through the peg holes are oblique relative to each other, and are preferably angled relative to each other in two dimensions.

[0011] In use for stabilization of Colles' fracture, the plate is positioned with its first side against the volar side of the radius and bone screws are inserted through the bone screw holes into the radius to secure the plate to the radius. The bone fragments are aligned and a drill is used to drill holes into the bone fragments in alignment with the axes of the peg holes. The pegs are then inserted through the peg holes and into the holes in the bone, and the heads of the pegs are threadably engaged in the head portion of the plate. The pegs define a support framework which is preferably divergent both medial and laterally such that the pegs are arranged to follow the contour of subchondral bone of the bone being stabilized. The fixation system thereby secures the bone fragments in their proper orientation.

[0012] According to another embodiment, a fixation system includes a device having a proximal shaft portion defining an intramedullary nail and relatively flat plate head portion, preferably horizontally and vertically offset relative to the shaft portion by a neck portion. The shaft portion includes screw holes, and the plate portion has a low, narrow profile and includes longitudinally displaced peg holes, each of which is adapted to orient a peg in a different orientation from the others.

[0013] In use, a relatively small incision is made in the skin, and the shaft portion is introduced through the incision and through the fracture location into the medullary canal of the bone, and the plate portion of the device is maneuvered against a surface of the bone at the metaphysis. The shaft portion is fixed relative to the bone with one or more screws, while pegs are inserted through holes drilled in alignment with the peg holes and define a framework for stabilization and support of subchondral bone fragments. Moreover, as the pegs preferably enter the subchondral fragments from a plurality of directions, additional fixation of the device into the bone is provided.

[0014] The fixation system can be adapted to treatment of fractures at multiple sites. For example, the distal radius, the proximal humerus, the distal femur, the proximal tibia, the distal tibia, and the hip are all suitable for application of the system of the invention.

[0015] Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.

[0016] FIG. 1 is an illustration of an extremity subject to a Colles' fracture;

[0017] FIG. 2 is a top volar view of a fixation system specifically adapted for a distal radius fracture according to a first embodiment of the invention;

[0018] FIG. 3 is a side view of a peg with a non-threaded shaft according to an embodiment of the fixation system of the invention;

[0019] FIG. 3a is a side view of a peg with a threaded shaft according to an embodiment of the fixation system of the invention;

[0020] FIG. 4 is a side view of a bone screw of an embodiment of the fixation system of the invention;

[0021] FIG. 5 is a side view of an embodiment of the fixation system of the invention;

[0022] FIG. 6 is a front end view of an embodiment of the volar fixation system of an embodiment of the invention;

[0023] FIG. 7 is an exploded side view of the right hand volar plate and guide plate according to the first embodiment of the fixation system of the invention;

[0024] FIG. 8 is a side view of the guide plate positioned on the right hand volar plate to provide drill guide paths in accord with the invention;

[0025] FIG. 9 is an illustration of the first embodiment of the volar fixation system provided in situ aligning and stabilizing a Colles' fracture;

[0026] FIG. 10 is a top volar view of a left hand volar fixation system according to the second embodiment of the invention;

[0027] FIG. 11 is a lateral side view of the left hand volar fixation system according to the second embodiment of the invention;

[0028] FIG. 12 is a bottom view of the left hand volar fixation system according to the second embodiment of the invention;

[0029] FIG. 13 is an enlarged side elevation of a bone peg according to the second embodiment of the volar fixation system of the invention;

[0030] FIG. 14 is a proximal end view of the bone peg of FIG. 13;

[0031] FIG. 15 is first partial top view of the head portion of the left hand volar plate according to the second embodiment of the volar fixation system of the invention;

[0032] FIGS. 16-19 are section views across line 16-16, 17-17, 18-18, and 19-19, respectively in FIG. 15;

[0033] FIG. 20 is second partial top view of the head portion of the left hand volar plate according to the second embodiment of the volar fixation system of the invention;

[0034] FIGS. 21-24 are section views across line 21-21, 22-22, 23-23, and 24-24, respectively in FIG. 20;

[0035] FIG. 25 is a broken partial longitudinal section view across a distal end of a third embodiment of the volar fixation system of the invention;

[0036] FIG. 26 is a proximal perspective view of a bone peg according to the third embodiment of the invention;

[0037] FIGS. 27 and 28 are proximal and distal perspective views, respectively, of a set screw according to the third embodiment of the invention;

[0038] FIG. 29 is a distal end top perspective view of a fourth embodiment of a fixation device of the invention;

[0039] FIG. 30 is a proximal end top perspective view of the fixation device of FIG. 29;

[0040] FIG. 31 is a distal end bottom perspective view of the fixation device of FIG. 29;

[0041] FIG. 32 is a broken top view of the fixation device of FIG. 29; and

[0042] FIG. 33 is a broken longitudinal section view taken along line 33-33 in FIG. 32.

[0043] Turning now to FIGS. 2 through 4, a first embodiment of a fixation system 100 for aligning and stabilizing multiple bone fragments in a Colles' fracture generally includes a substantially rigid T-shaped plate 102 intended to be positioned against the volar side of the radial bone, a plurality of preferably self-tapping bone screws 104 for securing the plate 102 along a non-fractured portion of the radial bone, and a plurality of bone pegs 108, 108a which extend from the plate 102 and into bone fragments of a Colles' fracture.

[0044] Referring to FIGS. 2, 5 and 6, more particularly, the T-shaped plate 102 defines a relatively flat head portion 116 angled upwards relative to an elongate relatively flat shaft portion 118, a first side 120 which is intended to contact the bone, and a second side 122 opposite the first side. As the head portion and shaft portion are angled relative to each other, the first side preferably generally defines two planar portions. The angle between the head portion 116 and the shaft portion 118 is preferably approximately 18 and bent at a radius of approximately 1.00 inch (FIG. 5). The distal edge 121 of the head portion 116 is preferably angled proximally toward the medial side at an angle , e.g., 5, relative to a line P, which is perpendicular to the shaft portion. In one embodiment, the head portion 116 preferably has a width of 0.913 inch and a greatest proximal-distal dimension (i.e., from the corner of angle to the shaft portion) of approximately 0.69 inch, and the shaft portion preferably has a width of 0.375 inch and a length of 1.40 inches, though alternative dimensions may be provided for plates adapted for various individuals, or for plates adapted for use on bones other than the radius. The plate 102 preferably has a thickness of at least approximately 0.098 inch. The plate 102 is preferably made from a titanium alloy, such as Ti-6A-4V.

[0045] The shaft portion 118 includes three preferably countersunk screw holes 124, 126, 128 for the extension of the bone screws 104 therethrough. One of the screw holes, 128, is preferably generally elliptical (or oval).

[0046] The head portion 116 includes four threaded peg holes 130, 132, 134, 136 for individually receiving the pegs 108, 108a therethrough. According to a first preferred aspect of the first embodiment of the invention, the peg holes 130, 132, 134, 136, each preferably 0.100 inch in diameter, are preferably substantially linearly arranged along the head portion 116, and are provided such that the adjacent peg holes are provided further distally in a medial to lateral direction along the second side. Alternatively, the peg holes may be arranged along a smooth curve such as a shallow parabolic curve.

[0047] The peg holes define axes A₁, A₂, A₃, A₄ which are oblique (not parallel) relative to each other, and more preferably are angled in two dimensions (medial/lateral and proximal/distal) relative to each other; i.e., the pegs once inserted into the peg holes are also angled in two dimensions relative to each other. More particularly, the first axis A₁ of the first peg hole 130 (that is, the most proximal and medial peg hole) is preferably directed normal to the first side 120 of the head portion 116. The axis A₂ of the adjacent peg hole 132, i.e., the second axis, is preferably angled approximately 1-7 distal and lateral relative to the first axis A₁, and more preferably approximately 2.5 distal and lateral relative to the first axis A₁. The axis A₃ of the peg hole 134 laterally adjacent the second peg hole 132, i.e., the third axis, is preferably angled approximately 7-13 distal and lateral relative to the first axis A₁, and more preferably approximately 10 distal and lateral relative to the first axis A₁. The axis A₄ of the peg hole 134 laterally adjacent the third peg hole 132, i.e., the fourth axis, is preferably angled approximately 10-30 distal and lateral relative to the first axis A₁, and more preferably approximately 20 distal and lateral relative to the first axis A₁. The second side of the head portion 116, distal of the peg holes 130, 132, 134, 136 is preferably beveled.

[0048] Referring back to FIGS. 3 and 3a, the pegs 108, 108a, preferably approximately 0.872 inch in length, each have a threaded head 138 adapted to threadably engage the threads about the threaded peg holes 130, 132, 134, 136. Such dimensions permit the pegs to adequately support the bone fragments such that the bone is able to heal correctly. The pegs may have a relatively smooth shaft 140 (FIG. 3) or a threaded shaft (FIG. 3a). If threaded, the shafts 140a are preferably threaded at a pitch different from the threads on the head 138 of the pegs 108a. The pegs 108 are also preferably made from titanium alloy, and may be coated in a ceramic, e.g., titanium nitride, to provide a bone interface which will not adversely affect bone healing.

[0049] Turning now to FIGS. 7 and 8, the system 100 may also include a guide plate 146 which temporarily sits on the second side 122 of the volar plate 102 and includes guide holes 148, 150, 152, 154 (illustrated in overlapping section in FIG. 8) oriented according to the axes A₁, A₂, A₃, A₄ of the peg holes for guiding a drill into the bone fragments at the required orientation. That is, the guide holes together with the peg holes define a drill guide path along the axes with sufficient depth to accurately guide a drill (not shown) to drill holes at the desired pin orientations. The volar plate 102 and guide plate 146 are also preferably provided with mating elements, such as a plurality of holes 156, 158 on the second side of the volar plate (FIG. 2), and a plurality of protuberances 160 on the mating side of the guide plate (FIG. 7), to temporarily stabilize the guide plate on the volar plate during the hole drilling process. Alternatively, a threaded drill guide or other guide means may be used to guide a drill to drill holes in appropriate orientations relative to the peg hole axes, as is known in the art.

[0050] Referring to FIGS. 2 through 9, in use, the volar plate 102 is positioned with its first side 120 against the volar side of the radius. Bone screws 104 (either self-tapping or inserted with the aid of pre-drilled pilot holes) are inserted through the bone screw holes 124, 126, 128 into the radius bone 10 to secure the volar plate 102 to the radius. The bone fragments 16, 18, 20 are then aligned with the radius 10. Next, the guide plate 146 is positioned on the second side of the volar plate. A drill, guided by a guide path formed by the peg holes and the guide holes, drills holes into and between the bone fragments 16, 18, 20 (and possibly also a portion of the integral radius, depending upon the particular location and extent of the fracture), and the guide plate is then removed. The pegs 108, 108a (any combination thereof including solely non-threaded shaft pegs 108 and solely threaded shaft pegs 108a) are then inserted through the peg holes 130, 132, 134, 136 and into the holes drilled into the fragments, and the heads of the pegs are threadably engaged in the volar plate. The pegs 108, 108a, extending through the oblique-axis peg holes 130, 132, 134, 136, are positioned immediately below the subchondral bone of the radius and support the bone fragments for proper healing. The volar fixation system thereby secures the bone fragments in their proper orientation.

[0051] Referring to FIGS. 10-12, a second embodiment of a volar plate 210, substantially similar to the first embodiment (with like parts having numbers incremented by 100) and used in substantially the same manner as the first embodiment is shown. The plate 210 preferably has a length of approximately 2.35 inches, which is approximately 0.35 inch greater than in the first embodiment. This additional length accommodates an extra bone screw hole 229 in the shaft portion of the volar plate such that the volar plate preferably includes four bone screw holes 224, 226, 228, 229. The additional bone screw in screw hole 229 increases plate stability over the three holes of the first embodiment. The plate 210 preferably tapers in thickness from the shaft portion 218 to the head portion 216. A preferred taper provides a proximal shaft portion 218 thickness of approximately 0.098 inch and head portion 216 thickness of approximately 0.078 inch. The taper decreases the thickness of the head portion 216 relative to the shaft portion such that the weight of the volar plate is reduced and an improved tendon clearance is provided. The distal edge of the head portion 216 has an increased taper (preferably approximately 60 relative to a line normal to the head) to a distal edge 221. The edge 221 is broken (i.e., made blunt) to prevent irritation or disturbance to the surrounding anatomy.

[0052] The head portion 216 includes four threaded peg holes 230, 232, 234, 236 for individually receiving pegs 208 therethrough (FIGS. 13 and 14), and a guide hole 256 for alignment of a guide plate. According to a preferred aspect of the second embodiment of the invention, the peg holes 230, 232, 234, 236, preferably 0.100 inch in diameter, are preferably linearly arranged along the head portion 216, and are provided such that the adjacent peg holes are provided further distally in a medial to lateral direction along the first and second sides. Referring to FIG. 15, more particularly, according to a preferred dimensions of the second embodiment of the invention, the center of peg hole 230 is located approximately 0.321 inch proximal line P and approximately 0.750 inch medial of the lateral edge 237 of the head portion, the center of peg hole 232 is located approximately 0.306 inch proximal line P and 0.557 inch medial of the lateral edge 237, the center of peg hole 234 is located approximately 0.289 inch proximal line P and approximately 0.364 inch medial of the lateral edge 237, and the center of peg hole 236 is located approximately 0.272 inch proximal line P and approximately 0.171 inch medial of the lateral edge 237. As such, the distance from each of the peg holes to the distal edge 221 of the volar plate is relatively greater than in the first embodiment, and provides a preferred alignment with respect to the tapered distal edge 221.

[0053] Referring to FIGS. 15-24, in addition, as in the first embodiment, the peg holes define axes A₁, A₂, A₃, A₄ which are oblique relative to each other, and more preferably are angled in two dimensions (medial/lateral and proximal/distal) relative to each other; i.e., the pegs 208 once inserted into the peg holes are also angled in two dimensions relative to each other. More particularly, as in the first embodiment, the first axis A₁ of the first peg hole 230 is preferably directed normal (FIGS. 16 and 21) to the first side 220 of the head portion 216. The axis A₂ of peg hole 232 is preferably angled approximately 1-7 distal (FIG. 17) and approximately 1-7 lateral (FIG. 22) relative to the axis A₁, and more preferably approximately 2.5 both distal and lateral relative to axis A₁. The axis A3 of peg hole 234 is preferably angled approximately 7-13 distal (FIG. 18) and approximately 7-13 lateral (FIG. 23) relative to axis A₁, and more preferably approximately 10 both distal and lateral relative to axis A₁. Axis A₄ of the peg hole 234 is preferably angled approximately 10-30 distal (FIG. 19) and approximately 10-30 lateral (FIG. 24) relative to axis A₁, and more preferably approximately 20 both distal and lateral relative to axis A₁.

[0054] Referring to FIGS. 13 and 16-19, each of the peg holes has a countersunk portion 270, 272, 274, 276, respectively, for receiving the head 238 of peg 208. Countersunk portions 270, 272 are each preferably approximately 0.030 inch deep and threaded according to the head of the pegs, as described below. Countersunk portion 274 is preferably approximately 0.042 inch deep and likewise threaded. Countersunk portion 276 is preferably approximately 0.056 inch deep and also threaded. The respective depths of the countersunk portions are adapted to better accommodate the heads 238 of the pegs 208 relative to the respective axes of the peg holes.

[0055] Referring to FIGS. 13 and 14, the pegs 208, preferably approximately 0.872 inch in length, each have a threaded head 238 adapted to threadably engage threads about the peg holes 230, 232, 234, 236 and cylindrical shaft 240 which may be threaded or non-threaded. The heads 238 preferably include a no. 5 thread 280 at a count of 44 per inch. In addition, the heads 238 are rounded and include a hex socket 282 to facilitate stabilized threading into the peg holes. This design accommodates the reduced thickness of the volar plate at the head portion 216. The shafts 240 are preferably approximately 0.0792 inch (2 mm) in diameter and 0.765 inch in length. Such dimensions permit the pegs to adequately support the bone fragments such that the bone is able to heal correctly. The pegs 208 are also preferably made from titanium alloy, and are preferably tiodized to provide a strong finish which does not adversely affect bone healing.

[0056] From the foregoing embodiments, it is appreciated that the peg holes define a plurality of axes at least two of which are oblique relative to each other and at least one of which is oblique relative to the lower surface of the head of the plate immediately surrounding such hole. In addition, the threaded peg holes define axes which diverge in a direction away from the lower surface of the plate. As such, pegs coupled within such holes define a support framework which is preferably divergent both medial and laterally such that the pegs are arranged to follow the contour of subchondral bone of the bone being stabilized.

[0057] Furthermore, the head portion provides substantial support structure both proximal and distal of the threaded holes for supporting the bone fragments. So that substantial surface structure of the plate is provided for the support, preferably the peg holes define less than fifty percent of the area of the head portion, as clearly shown in FIGS. 2 and 15. Furthermore, as also shown in the embodiment of FIG. 15, a greater area of the head portion is preferably provided distal of the arrangement of the peg holes (on the side of the pegs holes opposite the shaft portion) relative to the area on the head portion proximal of the arrangement of peg holes (on the portion of the head portion adjacent the shaft portion). This large distal area provides a buttress for supporting bone fragments thereunder.

[0058] Turning now to FIG. 25, a volar fixation system 300 according to a third embodiment is shown in which each peg can be articulated through a range of angles within a respective peg hole and fixed at a desired angle within the range. The system includes a volar plate 302, four pegs 308, and four set screws 310, as well as bone screws, not shown but described above, for mounting the volar plate to the radius.

[0059] The volar plate 310 is substantially similar to the first or second embodiments, with the exception of the shape of the peg holes described below, and is used in substantially the same manner as the first embodiment. Each peg hole 312 in the volar plate includes a cylindrical upper bore 314 provided with threads 316 and a lower portion 318 having a radius of curvature. The surface 320 of the lower portion and/or the surface 330 of the head of the peg is preferably roughened, e.g., by electrical, mechanical, or chemical abrasion, or by the application of a coating or material having a high coefficient of friction. The lower opening 322 of each peg hole includes a circumferential bevel 324.

[0060] Referring to FIGS. 25 and 26, each peg 308 includes a head 330 and a cylindrical shaft 332. The proximal portion 334 of the head 330 includes a cup 336 having an outer radius R_o substantially corresponding to the radius of the lower portion 318 of the peg holes 312, and a relatively smaller inner radius R_i of curvature. The head 330 defines preferably approximately 160 of a sphere. The shaft 332 includes a slight taper 336 at the intersection with the head 330, and a rounded distal end 338. According to a preferred manufacture of the pegs 308, the cylindrical shaft 332 is first provided with a sphere (not shown) or a hemisphere (not shown) at a proximal end. If a sphere is provided, it is cut to a hemisphere. The hemisphere is then hollowed and further reduced to the 160 shape. Finally, the taper 336 is provided at the intersection.

[0061] Turning now to FIGS. 25, 27 and 28, each set screw 310 includes a proximal hex socket 340, circumferential threads 342 adapted to engage the threads 316 of the upper bore 314 of the peg hole, and distal hemispherical portion 344 having substantially the same radius of curvature as the inner radius of curvature of the cup 336, and preferably substantially smaller than a radius of the peg holes 312.

[0062] In accord with the third embodiment, the volar plate is positioned on the radius, a hole is drilled through the elliptical screw hole on the volar plate and into the radius. A bone screw is inserted through the plate and into the bone. The fractured bones are adjusted under the plate into their desired stabilized positions, and the bone screw is tightened. Then, through the peg holes, the surgeon drills holes into the bone for the stabilization pegs. Unlike the previous embodiments, the holes may be drilled at any angle within a predefined range, and preferably at any angle within a range of 20 relative to an axis normal A_N to the lower surface of the head of the volar plate. Each hole may be drilled at the same angle or at relatively different angles. After each hole is drilled, a peg 308 is inserted therein. The bevel 324 at the lower end 322 of the peg hole 312 and the taper 336 on the shaft cooperate to permit the peg to be oriented with greater angularity relative to the axis A_N, if required, as interference between the peg hole and peg shaft is thereby reduced. Once the peg 308 has been appropriately positioned within the peg hole, one of the set screws 310 is threaded into the upper bore 314 of the peg hole 312. The hemispherical portion 344 contacts the head 330 of the peg, seating in the concavity of the cup 336. As the set screw 310 is tightened, the head of the peg, which may be roughened, is sandwiched between the set screw and the roughened inner surface of the lower portion of the peg hole, thereby securing the peg in the selected orientation. The other pegs are similarly positioned and angularly fixed.

[0063] Turning now to FIGS. 29 through 33, a fixation device 410 for the treatment of a fracture at an end of a long bone, i.e., a metaphyseal fracture, is provided. The device 410 is preferably made of metal, e.g., titanium or stainless steel, and includes an intramedullary nail shaft portion 412 and a plate-like head portion 414 that is preferably horizontally and vertically offset relative to the shaft portion at a neck portion (or transition zone) 16. As such, the shaft portion 412 and the head portion 414 are fixed in a parallel, but non-coaxial relationship, with the head portion 414 longitudinally displaced relative to the shaft portion 412.

[0064] The shaft portion 412 is preferably substantially circular in cross section and includes a tapered resilient (flexible) section 420, and a relatively rigid section 422 generally substantially larger in diameter adjacent the shoulder portion 416. The rigid section 422 preferably tapers toward and into the resilient section 420. Referring to FIGS. 32 and 33, the rigid section 422 of the shaft portion 412 preferably includes two optionally threaded screw holes 424, 426 preferably extending vertically through the diameter of the shaft portion 412 and longitudinally displaced along the length of the rigid section 422. The screw holes 424, 426, if threaded are adapted to receive machine screws as described in detail in co-pending U.S. Ser. No. 10/315,787, and if not threaded are adapted to receive cortical screws, as described in detail in co-pending U.S. Ser. No. 10/159,611, both of which are hereby incorporated by reference herein in their entireties.

[0065] With respect to FIGS. 29 through 33, the plate-like head portion 414 is substantially rigid and has a low and narrow profile. The head portion 414 has a slightly concave bottom surface 444 (adapting the head portion to the anatomy) and a slightly convex upper surface 446 (reducing potential irritation of tendons and other tissue). The concave and convex surfaces 444 and 446 may be defined by facets approximating curved surfaces. The head portion 414 also includes preferably three longitudinally displaced, threaded peg holes 450, 452, 454, each of which is preferably adapted to orient a respective peg (e.g., pegs 108 and 108a of FIGS. 3 and 3a) in a different orientation from the others; i.e., the axes of the peg holes are oblique relative to each other so that the pegs inserted therethrough diverge away from the bottom surface 444 and define a framework under the subchondral surface which supports the fracture. In use, the shaft portion 412 of the device 410 is inserted in the intramedullary canal and the plate-like head portion 414 is provided external of the bone, as described in detail in previously incorporated U.S. Ser. Nos. 10/315,787 and 10/159,611.

[0066] There have been described and illustrated herein embodiments of an orthopedic fixation system suitable for numerous applications related to the fixation of various bone fractures. While embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while in one embodiment a volar plate for fixation of a fracture at the distal radius has been shown and described, it is appreciated that a plate with divergent threaded peg holes may be optimized in shape and size for placement on the dorsal radius or for fractures of other bones, such as of the ulna, humerus, femur, tibia, fibula, adjacent the ankle joint, etc. Furthermore, while particular materials for the elements of the system have been disclosed, it will be appreciated that other materials may be used as well. In addition, fewer or more peg holes and pegs than shown may be used, preferably such that at least two pegs angled in two dimensions relative to each other are provided. Also, while a right-handed volar plate for the distal radius is described with respect to an embodiment of the invention, it will be appreciated that both right- and left-handed models are intended, with such alternate models being mirror images of each other. Also, the plate, nail-plate device, and pegs may be provided in different sizes adapted for implant into different size people. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.