US20010011172A1 - Volar fixation system with articulating stabilization pegs - Google Patents

Abstract

A volar fixation system includes a T-shaped plate intended to be positioned against the volar side of the radial bone, a plurality of bone screws for securing the plate along an non-fractured portion of the radial bone, and a plurality of bone pegs which extend from the plate and into bone fragments of a Colles' fracture. The plate is a T-shaped plate including a plurality of screw holes and a plurality of threaded peg holes. According to a preferred aspect of the invention, pegs can be articulated through a range of angles within respective peg holes and fixed at a desired angle within the range. The volar plate is positioned against the radius and screws are inserted through the screw holes to secure the volar plate to the radius. The bone fragments are aligned, and the holes are drilled through the peg holes into the fragments. The pegs are inserted through the peg holes and into the drilled holes in the bone. The pegs can be oriented at various angles relative to an axis normal to the lower surface of the plate. For each peg, once the peg has been appropriately positioned within the peg hole, a set screw is thread into the peg hole and tightened, thereby securing the peg in the selected orientation.

Description

• This application is a continuation-in-part of both U.S. patent application Ser. No. 09/524,058, field Mar. 13, 2000 and U.S. patent application Ser. No. 09/495,854, filed Feb. 1, 2000, which are each hereby incorporated by reference herein in their entireties.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0002]
• This invention relates broadly to surgical devices. More particularly, this invention relates to a bone fixation system, and particularly to a fixation system adapted to fixate a Colles' (or distal radial) fracture.[0003]
• 2. State of the Art[0004]
• Referring to FIG. 1, a Colles' fracture is a fracture resulting from compressive forces being placed on the[0005]distal radius10, and which causes backward displacement of thedistal fragment12 and radial deviation of the hand at thewrist14. Often, a Colles' fracture will result inmultiple bone fragments16,18,20 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.
• 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 the 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.[0006]
SUMMARY OF THE INVENTION
• It is therefore an object of the invention to provide an improved fixation and alignment system for a Colles' fracture.[0007]
• It is another object of the invention to provide a volar fixation system which desirably aligns and stabilizes multiple bone fragments in a distal radial fracture to permit proper healing.[0008]
• It is also an object of the invention to provide a volar fixation system which is highly adjustable to provide a customizable framework for bone fragment stabilization.[0009]
• In accord with these objects, which will be discussed in detail below, a volar fixation system is provided which generally includes a T-shaped plate intended to be positioned against the volar side of the radial bone, a plurality of bone screws for securing the plate along a non-fractured portion of the radial bone, and a plurality of bone pegs which extend from the plate and into bone fragments of a Colles' fracture.[0010]
• The plate is generally a T-shaped plate defining an elongate body, a head portion angled relative to the body, a first side which is intended to contact the bone, and a second side opposite the first side. The body 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 non-linearly arranged. According to a second embodiment, the peg holes are preferably linearly arranged. In either embodiment, the peg holes are positioned increasingly distal in a medial to lateral direction along the second side. According to a third embodiment, which preferably uses a volar plate with peg holes arranged according to either of the first and second embodiments, the pegs are adjustable relative to the peg holes and can be independently fixed in selectable orientations.[0011]
• In use, the volar 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 volar plate to the radius. The bone fragments are then aligned and the guide plate is positioned on the second side of the volar plate. A drill drills holes into the bone fragments.[0012]
• The pegs are then inserted through the peg holes and into the holes in the bone. In some embodiments, the heads of the pegs are threadably engaged in the volar plate. In other embodiments, the pegs are inserted into the peg holes and into the drilled holes at an angle chosen by the surgeon, and a set screw is inserted over each peg to lock the peg in the volar plate at the chosen orientation. The volar fixation system thereby stabilizes and secures the bone fragments in their proper orientation.[0013]
• 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.[0014]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an illustration of an extremity subject to a Colles' fracture;[0015]
• FIG. 2 is a top volar view of a right hand volar fixation system according to a first embodiment of the invention;[0016]
• FIG. 3 is a side view of a bone peg according to the first embodiment of the volar fixation system of the invention;[0017]
• FIG. 4 is a side view of a bone screw of the volar fixation system of the invention;[0018]
• FIG. 5 is a side view of the right hand volar plate of the volar fixation system according to the first embodiment of the invention;[0019]
• FIG. 6 is a front end view of the right hand volar plate of the volar fixation system according to the first embodiment of the invention;[0020]
• 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;[0021]
• 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;[0022]
• FIG. 9 is an illustration of the first embodiment of the volar fixation system provided in situ aligning and stabilizing a Colles' fracture;[0023]
• FIG. 10 is a top volar view of a left hand volar fixation system according to the second embodiment of the invention;[0024]
• FIG. 11 is a lateral side view of the left hand volar fixation system according to the second embodiment of the invention;[0025]
• FIG. 12 is a bottom view of the left hand volar fixation system according to the second embodiment of the invention;[0026]
• FIG. 13 is an enlarged side elevation of a bone peg according to the second embodiment of the volar fixation system of the invention;[0027]
• FIG. 14 is a proximal end view of the bone peg of FIG. 13;[0028]
• 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;[0029]
• FIGS.[0030]16-19 are section views across line16-16,17-17,18-18, and19-19, respectively in FIG. 15;
• 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;[0031]
• FIGS.[0032]21-24 are section views across line21-21,22-22,23-23, and24-24, respectively in FIG. 20;
• 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;[0033]
• FIG. 26 is a proximal perspective view of a bone peg according to the third embodiment of the invention; and[0034]
• FIGS. 27 and 28 are proximal and distal perspective views, respectively, of a set screw according to the third embodiment of the invention.[0035]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Turning now to FIGS. 2 through 4, a first embodiment of a[0036]volar fixation system100 for aligning and stabilizing multiple bone fragments in a Colles' fracture generally includes a substantially rigid T-shapedplate102 intended to be positioned against the volar side of the radial bone, a plurality of preferably self-tappingbone screws104 for securing theplate102 along a non-fractured portion of the radial bone, and a plurality of bone pegs108 which extend from theplate102 and into bone fragments of a Colles' fracture.
• Referring to FIGS. 2, 5 and[0037]6, more particularly, the T-shapedplate102 defines ahead portion116, anelongate body portion118 angled relative to the head portion, afirst side120 which is intended to contact the bone, and asecond side122 opposite the first side. Thefirst side120 at the head portion is preferably planar, as is the first side at the body portion. As the head portion and body portion are angled relative to each other, the first side preferably defines two planar portions. The angle θ between thehead portion116 and thebody portion118 is preferably approximately 18° and bent at a radius of approximately 1.00 inch (FIG. 5). Thedistal edge121 of thehead portion116 is preferably angled proximally toward the medial side at an angle α, e.g., 5°, relative to a line P, which is perpendicular to the body portion. Thehead portion116 preferably has a width of 0.913 inch and a greatest proximal-distal dimension (i.e., from the corner of angle α to the body portion) of approximately 0.69 inch, and the body portion preferably has a width of 0.375 inch and a length of 1.40 inches. Theplate102 preferably has a thickness of approximately 0.098 inch. Theplate102 is preferably made from a titanium alloy, such as Ti-6A-4V.
• The[0038]body portion118 includes three preferably countersunk screw holes124,126,128 for the extension of thebone screws104 therethrough. Thefirst screw hole124 has a center preferably 0.235 inch from the end of the body portion, thesecond screw hole126 has a center preferably 0.630 inch from the end of the body portion, and thethird screw hole128 is preferably generally elliptical (or oval) and defines foci-like locations at 1.020 inches and 1.050 inches from the end of the body portion. Thehead portion116 includes four threaded peg holes130,132,134,136 for individually receiving thepegs108 therethrough. According to a first preferred aspect of the first embodiment of the invention, the peg holes130,132,134,136, preferably 0.100 inch in diameter, are preferably non-linearly arranged along thehead portion116, and are provided such that the adjacent peg holes are provided further distally in a medial to lateral direction along the second side. More particularly, according to a preferred aspect of the first embodiment of the invention, the peg holes are preferably arranged along a parabolic curve, with the center ofpeg hole130 located approximately 0.321 inch proximal line P and approximately 0.719 inch medial of the lateral edge137 of the head portion, the center ofpeg hole132 located approximately 0.296 inch proximal line P and approximately 0.544 inch medial of the lateral edge137, the center ofpeg hole134 located approximately 0.250 inch proximal line P and approximately 0.369 inch medial of the lateral edge137, and the center ofpeg hole136 located approximately 0.191 inch proximal line P and approximately 0.194 inch medial of the lateral edge137.
• In addition, according to a second preferred aspect of the first embodiment of the invention, the peg holes define axes A[0039]₁, A₂, A₃, A₄which 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 A₁of the first peg hole130 (that is, the most proximal and medial peg hole) is preferably directed normal to thefirst side120 of thehead portion116. The axis A₂of theadjacent peg hole132, 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 A₃of thepeg hole134 laterally adjacent thesecond peg hole132, 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 A₄of thepeg hole134 laterally adjacent thethird peg hole132, 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 thehead portion116, distal of the peg holes130,132,134,136 is preferably beveled.
• Referring back to FIG. 3, the[0040]pegs108, preferably approximately 0.872 inch in length, each have a threadedhead138 adapted to threadably engage the threads about the peg holes130,132,134,136, and have a relatively smooth non-threadedcylindrical shaft140. Theshafts140 are preferably approximately 0.0675 inch 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. Thepegs108 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.
• Turning now to FIGS. 7 and 8, the[0041]system100 preferably also includes aguide plate146 which temporarily sits on thesecond side122 of thevolar plate102 and includes guide holes148,150,152,154 (illustrated in overlapping section in FIG. 8) oriented according to the axes A₁, A₂, A₃, A₄of 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. Thevolar plate102 and guideplate146 are also preferably provided with mating elements, such as a plurality ofholes156,158 on the second side of the volar plate (FIG. 2), and a plurality ofprotuberances160 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.
• Referring to FIGS. 2 through 9, in use, the[0042]volar plate102 is positioned with itsfirst side120 against the volar side of the radius. Bone screws104 (either self-tapping or inserted with the aid of pre-drilled pilot holes) are inserted through the bone screw holes124,126,128 into theradius bone10 to secure thevolar plate102 to the radius. The bone fragments16,18,20 are then aligned with theradius10. Next, theguide plate146 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 fragments16,18,20 (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. Thepegs108 are then inserted through the peg holes130,132,134,136 and into the holes drilled into the fragments, and the heads of the pegs are threadably engaged in the volar plate. Thepegs108, extending through the oblique-axis peg holes130,132,134,136, are positioned immediately below the subcondylar 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.
• Referring to FIGS.[0043]10-12, a second embodiment of avolar plate210, substantially similar to the first embodiment (with like parts having numbers incremented by100) and used in substantially the same manner as the first embodiment is shown, Theplate210 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 extrabone screw hole229 in the body of the volar plate such that the volar plate preferably includes four bone screw holes224,226,228,229. The additional bone screw inscrew hole229 increases plate stability over the three holes of the first embodiment. Theplate210 preferably tapers in thickness from thebody portion218 to thehead portion216. A preferred taper provides aproximal body portion218 thickness of approximately 0.098 inch andhead portion216 thickness of approximately 0.078 inch. The taper decreases the thickness of thehead portion216 relative to the body such that the weight of the volar plate is reduced and an improved tendon clearance is provided. The distal edge of thehead portion216 has an increased taper (preferably approximately 600 relative to a line normal to the head) to adistal edge221. Theedge221 is broken (i.e., made blunt) to prevent irritation or disturbance to the surrounding anatomy.
• The[0044]head portion216 includes four threaded peg holes230,232,234,236 for individually receivingpegs208 therethrough (FIGS. 13 and 14), and aguide hole256 for alignment of a guide plate. According to a preferred aspect of the second embodiment of the invention, the peg holes230,232,234,236, preferably 0.100 inch in diameter, are preferably linearly arranged along thehead portion216, 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 ofpeg hole230 is located approximately 0.321 inch proximal line P and approximately 0.750 inch medial of thelateral edge237 of the head portion, the center ofpeg hole232 is located approximately 0.306 inch proximal line P and 0.557 inch medial of thelateral edge237, the center ofpeg hole234 is located approximately 0.289 inch proximal line P and approximately 0.364 inch medial of thelateral edge237, and the center ofpeg hole236 is located approximately 0.272 inch proximal line P and approximately 0.171 inch medial of thelateral edge237. As such, the distance from each of the peg holes to thedistal edge221 of the volar plate is relatively greater than in the first embodiment, and provides a preferred alignment with respect to the tapereddistal edge221.
• Referring to FIGS.[0045]15-24, in addition, as in the first embodiment, the peg holes define axes A₁, A₂/ A₃, A₄which 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., thepegs208 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 A₁of thefirst peg hole230 is preferably directed normal (FIGS. 16 and 21) to the first side220 of thehead portion216. The axis A₂ofpeg hole232 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 A₃ofpeg hole234 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 A₄of thepeg hole234 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.
• Referring to FIGS. 13 and 16-[0046]19, each of the peg holes has a countersunkportion270,272,274,276, respectively, for receiving thehead238 ofpeg208.Countersunk portions270,272 are each preferably approximately 0.030 inch deep and threaded according to the head of the pegs, as described below.Countersunk portion274 is preferably approximately 0.042 inch deep and likewise threaded.Countersunk portion276 is preferably approximately 0.056 inch deep and also threaded. The respective depths of the countersunk portions are adapted to better accommodate theheads238 of thepegs208 relative to the respective axes of the peg holes.
• Referring to FIGS. 13 and 14, the[0047]pegs208, preferably approximately 0.872 inch in length, each have a threadedhead238 adapted to threadably engage threads about the peg holes230,232,234,236, and have a relatively smooth non-threaded cylindrical shaft240. Theheads238 preferably include a no. 5thread280 at a count of 44 per inch. In addition, theheads238 are rounded and include ahex socket282 to facilitate stabilized threading into the peg holes. This design accommodates the reduced thickness of the volar plate at thehead portion216. The shafts240 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. Thepegs208 are also preferably made from titanium alloy, and are preferably ‘tiodized’ to provide a strong finish which does not adversely affect bone healing.
• Turning now to FIG. 25, a[0048]volar fixation system300 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 avolar plate302, fourpegs308, and four setscrews310, as well as bone screws, not shown but described above, for mounting the volar plate to the radius.
• The[0049]volar plate310 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. Eachpeg hole312 in the volar plate includes a cylindrical upper bore314 provided withthreads316 and alower portion318 having a radius of curvature. Thesurface320 of the lower portion and/or thesurface330 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. Thelower opening322 of each peg hole includes a circumferential bevel324.
• Referring to FIGS. 25 and 26, each[0050]peg308 includes ahead330 and acylindrical shaft332. The proximal portion334 of thehead330 includes acup336 having an outer radius Ro substantially corresponding to the radius of thelower portion318 of the peg holes312, and a relatively smaller inner radius R_iof curvature. Thehead330 defines preferably approximately 1600 of a sphere. Theshaft332 includes aslight taper336 at the intersection with thehead330, and a roundeddistal end338. According to a preferred manufacture of thepegs308, thecylindrical shaft332 is first provided with a sphere (not shown) or a hemispher (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, thetaper336 is provided at the intersection.
• Turning now to FIGS. 25, 27 and[0051]28, eachset screw310 includes aproximal hex socket340,circumferential threads342 adapted to engage thethreads316 of the upper bore314 of the peg hole, and distalhemispherical portion344 having substantially the same radius of curvature as the inner radius of curvature of thecup336, and preferably substantially smaller than a radius of the peg holes312.
• 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 then 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 fracture location 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[0052]_Nto 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, apeg308 is inserted therein. The bevel324 at thelower end322 of thepeg hole312 and thetaper336 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 thepeg308 has been appropriately positioned within the peg hole, one of theset screws310 is threaded into the upper bore314 of thepeg hole312. Thehemispherical portion344 contacts thehead330 of the peg, seating in the concavity of thecup336. As theset screw310 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.
• There have been described and illustrated herein embodiments of a volar fixation system and a method of aligning and stabilizing a Colles' fracture. While particular 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 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, while a particular number of screw holes in the volar plates and bone screws have been described, it will be understood another number of screw holes and screws may be provided. Further, fewer screws than the number of screw holes may be used to secure to the volar plate to the radius. Also, fewer or more peg holes and bone pegs may be used, preferably such that at least two pegs angled in two dimensions relative to each other are provided. Moreover, while in the first embodiment it is preferred that the peg holes lie along a parabolic curve, it will be appreciated that they can lie along another curve. In addition, while a particular preferred angle between the head portion and body portion has been disclosed, other angles can also be used. Furthermore, while particular distances are disclosed between the peg holes and line P, it will be appreciated that the peg holes may be provided at other distances relative thereto. Moreover, while particular preferred medial/lateral and proximal/distal angles for the peg hole axes has been disclosed, it will be appreciated that yet other angles may be used in accord with the invention. Also, while a right-handed volar plate is described with respect to the first embodiment, and a left-handed volar plate is described with respect to the second embodiment, it will be appreciated that each embodiment may be formed in either a right- or left-handed model, with such alternate models being mirror images of the models described. In addition, while a range of 200 in which the pins may articulate is disclosed, the peg holes and pegs may be modified to permit a greater or smaller range of articulation. Furthermore, while a hex socket is disclosed on the set screws for applying rotational force thereto, it will be appreciated that other rotational engagement means, e.g., a Phillips, slotted, star, rectangular, or other configuration may be used. In addition, aspects from each of the embodiments may be combined. 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.[0053]

Claims (27)

1. A volar fixation system, comprising:

(a) a substantially rigid plate including a distal head portion and a proximal body portion angled relative to said head portion,

said head portion defining a plurality of peg holes adapted to individually receive fixation pegs therethrough, said peg holes having an upper portion and a lower portion, said upper portion having a first thread, and said lower portion having spherical radius of curvature,

said body portion including at least one screw hole;

(b) a plurality of pegs each having a head portion and a shaft portion, said shaft portion sized to be received in said peg holes, and said head portion having an outer surface with substantially a same spherical radius of curvature as said lower portion of said peg holes; and

(c) a plurality of set screws each having a body including a second thread rotationally engageable with said first thread, and a proximal rotational engagement means for engaging said set screw and applying a rotational force thereto,

wherein when said pegs are provided into respective peg holes, each said peg may be positioned at any angle within a predefined range of angles relative to an axis normal to a lower surface of said head portion of said volar plate, and once so positioned, respective set screws when thread into said upper portions of said peg holes fix said pegs in their respective angles.

2. A volar fixation system according to

claim 1

, wherein:

said predefined range includes 200 relative to said axis normal to said lower surface of said head portion of said volar plate.

3. A volar fixation system according to

claim 1

, wherein:

said lower portion of each of said peg holes is processed to have a relatively high coefficient of friction.

4. A volar fixation system according to

claim 1

, wherein:

said outer surface of said head portion of each of said pegs is processed to have a relatively high coefficient of friction.

5. A volar fixation system according to

claim 1

, wherein:

said peg holes are linearly arranged.

6. A volar fixation system according to

claim 1

, wherein:

said head portion defines a medial side and a lateral side, and said peg holes are arranged in a generally medial to lateral direction wherein successive lateral peg holes are situated distally relative to adjacent peg holes.

7. A volar fixation system according to

claim 1

, wherein:

said peg holes lie along a curve.

8. A volar fixation system according to

claim 1

, wherein:

said head portion includes exactly four peg holes.

9. A volar fixation system according to

claim 1

, wherein:

a taper is provided at an intersection of said head and shaft of each of said pegs.

10. A volar fixation system according to

claim 9

, wherein:

a bevel is provided about a lower opening of each of said peg holes.

11. A volar fixation system according to

claim 1

, wherein:

each of said head portions of said pegs is concave, and each of said set screws includes a distal convex portion seating with said head portions.

12. A volar fixation system according to

claim 11

, wherein:

said concave and convex portions are each defined by a substantially same radius.

13. A volar fixation system according to

claim 1

, wherein:

said outer surface of said head portion defines less than a hemisphere.

14. A volar fixation system according to

claim 1

, wherein:

said rotational engagement means of each of said set screws is a hex socket.

15. A volar fixation system according to

claim 1

, wherein:

said shaft portion of each of said pegs is a non-threaded cylinder.

16. A volar fixation plate, comprising:

a substantially rigid plate including a distal head portion and a proximal body portion angled relative to said head portion,

said head portion defining a plurality of peg holes adapted to individually receive fixation pegs therethrough, said peg holes having an upper portion and a lower portion, the lower portion having spherical radius of curvature,

said body portion including at least one screw hole.

17. A volar fixation plate according to

claim 16

, wherein:

said upper portion includes a thread.

18. A volar fixation plate according to

claim 16

, wherein:

said lower portion is processed to have a relatively high coefficient of friction.

19. A volar fixation plate according to

claim 16

, wherein:

said peg holes are linearly arranged.

20. A volar fixation plate according to

claim 16

, wherein:

said head portion defines a medial side and a lateral side, and said peg holes are arranged in a generally medial to lateral direction wherein successive lateral peg holes are situated distally relative to adjacent peg holes.

21. A volar fixation plate according to

claim 16

, wherein:

said peg holes lie along a curve.

22. A volar fixation plate according to

claim 16

, wherein:

said head portion includes exactly four peg holes.

23. A peg for insertion into a peg hole in a fracture fixation system, comprising:

(a) a head having an outer surface with a first substantially spherical radius of curvature and a concavity with a second substantially spherical radius of curvature, said head defining less than a hemisphere; and

(b) a cylindrical shaft coupled to said head, said shaft including a taper adjacent said head.

24. A peg according to

claim 23

, wherein:

said outer surface of said head portion is processed to have a relatively high coefficient of friction.

25. A set screw for set a peg in a peg hole, comprising:

a body including a thread, a proximal rotational engagement means for engaging said set screw and applying a rotation force thereto, and a distal hemispherical portion.

26. A set screw according to

claim 25

, wherein:

said distal hemispherical portion defines a radius smaller than a radius of said body.

27. A set screw according to

claim 25

, wherein:

said rotational engagement means is a hex socket.

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