Method for the fixation of bone

An apparatus for fixation of a fractured bone. The apparatus includes a first elongation member that is able to at least partially be inserted into two portions of the bone, as well as a second elongated member that is operable to also be partially inserted into the two portions of the bone. The first and second elongated members include an abrasive surface that is able to resist relative rotation between elongated members and a fixation clamp to which the locking members are secured.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to fixation devices for stabilizing two portions of 
bone, and more particularly to a method and apparatus for the fixation of 
bone fractures. 
2. Description of the Related Art 
Repairs of fractures of the distal radius and other small bones of the 
hand, wrist, and distal forearm often present particular difficulties. 
Fracture of the distal radius, often referred to by eponyms such as 
Colles' fractures, Smith's fracture, or Barton's fracture (herein referred 
to as Colles' fracture), are commonly unstable and may involve 
complications such as avulsion of the ulnar styloid, tearing of the 
collateral ulnar ligament, marked displacement of bone fragments from the 
distal radius or ulna, or derangement of the distal radioulnar joint. 
Injury to the nearby median nerve by bone spicules may result in sensory 
and motor paralysis. Persistent compression of the ulnar nerve creates 
symptoms of carpal tunnel syndrome, which may require operative divension 
of the volar carpal ligament for relief. 
There are two general types of devices which may be used to achieve 
fixation and, therefore, repair of a Colles' fracture. These devices are 
generally referred to as external fixation devices and internal fixation 
devices. External fixation devices are those devices that stabilize a 
fracture through direct penetration of percutaneous pins into bone and 
anchorage of the pins to external devices. In contrast, internal fixation 
devices are those devices that are located completely internal to the 
body. External fixation devices present several key advantages over 
internal fixation devices, including simplicity of the operative procedure 
and minimal disturbance of the bone biology, and decreased risk of deep 
infection and subsequent nonunion. External fixation is particularly 
indicated in cases of bone loss to preserve skeletal length. 
Techniques of closed reduction and external immobilization using external 
fixation devices have been advocated for repair of Colles' fractures. Such 
unstable fractures of the distal radius may be treated with small external 
fixators with pins implanted in the distal radial epiphysis to allow for 
early wrist joint mobility. Such external fixation devices are particular 
advantageous in allowing skeletal distraction and preservation of bone 
alignment and bone length. 
A variety of small external fixators are currently available for 
application of external fixation principles to small bones, such as the 
hand and wrist. Brazilian Patent No. 62 00 124 U discloses an external 
fixation device having percutaneous intramedullary pins and an external 
clamp with a fixator coupling device for stabilization of distal fractures 
of the radius, including those defined as Colles' fractures. This device 
is designed to prevent migration of the frame structure and to promote 
rotational stability. Because the fixation pins have a smooth surface, 
however, rotational stability of the pins in relation to the fixator 
coupling device is not insured. Additionally, because the fixator coupling 
device has cylindrical attachment grooves to receive the cylindrical ends 
of the pins to the fixator coupling device, rotational forces are largely 
unopposed, allowing potential rotation of the pins with resulting 
instability of the device. Rotational instability is especially likely 
with this device during the healing process when adjacent muscles and 
tendons are in use. 
Furthermore, the device disclosed in Brazilian Patent No. 62 00 124 U is 
constructed from a radiodense substance which does not allow easy 
verification by X-ray of bone alignment during the course of stabilization 
and healing of the fracture. Additionally, the external clamp of the 
fixator coupling device is large and bulky, making trauma to the device 
more likely and subsequent disruption of bone union. The bulkiness of the 
clamp also makes the desired use of the associated muscles, tendons, and 
joints during the healing process less likely. 
SUMMARY OF THE INVENTION 
In the preferred embodiment, the present invention relates to a method and 
apparatus for fixation of bone of the distal forearm, hand and wrist after 
fracture. The device of the present invention is especially useful for 
stabilization of fractured bones of the distal radius, often called 
Colles' fractures. Fractures of the distal radius are commonly unstable 
fractures that must be stabilized in a manner such that reduction of the 
fracture is maintained at the same time that early use of the associated 
muscles, tendons, and joints is allowed to prevent atrophy and stiffness. 
The device of the present invention includes a first elongation member that 
is operable to be at least partially inserted to a first and second 
portion of bone and a second elongation member that is operable to be at 
least partially inserted to a first and second portion of bone. The 
apparatus further includes a fixation clamp for securing the first 
elongation member to the second elongated member. In addition, the 
apparatus also includes an abrasive surface on a portion of the first 
elongated member and on a portion of the second elongated member. The 
abrasive surfaces are operable to resist relative rotation between the 
fixation clamp and the first and second elongated members. Rotational 
stability is promoted by these abrasive surfaces, and migration of the 
device is reduced. 
The first and second elongated members may each include a tapered portion 
for insertion into bone and an untapered portion that protrudes from the 
skin when the tapered portion is inserted into bone. The tapered portions 
of the elongated members allow ease of insertion of the elongated members 
into the fractured area of bone. The untapered portions of the first and 
second elongated members that protrude from the skin are secured to one 
another by a fixation clamp for securing the first and the second 
elongated members together. The fixation clamp may have upper and lower 
locking members which may each include angled grooves to receive the 
untapered portions of the elongated fixation members that are above the 
surface of the skin. The fixation clamp may also induce a screw for 
compression of the upper locking member against the lower locking member 
after portions of the untapered portions of the first elongated member and 
the second elongated member are placed within the angled grooves. The 
angled grooves of the first and second locking members firmly secure the 
untapered portions of the elongated members as the fixation clamp is 
tightened. The angled apertures of the first and second locking members 
and the abrasive surface of the elongated members increase the resistance 
to rotation of the untapered portions of the elongated members within the 
fixation clamp so that relatively smaller locking members can be utilized. 
The fixation clamp may also be constructed of radiolucent material to 
allow visualization of fracture reduction throughout the healing process. 
Accordingly, an advantage of the present invention is to provide a method 
and apparatus for the fixation of bone following fracture of the distal 
forearm, wrist, or hand in which the fractured bones are stabilized in a 
reduced position by two elongated members that are each anchored to 
external means for securing the elongated members. 
Another advantage of the present invention is to provide a method and 
apparatus for fixation of bone which reduces the possibility of rotation 
between the elongating members. In this regard, the present invention 
includes the abrasive surfaces on a portion of the elongated members, the 
angled receiving grooves of the locking members, and the fixation clamp to 
securely anchor the elongated members to the locking members and within 
the reduced and fixed bones. 
A further advantage of the present invention is to provide a method and 
apparatus for the fixation of bone which is at least partially radiolucent 
to facilitate visualization of fracture reduction and placement of the 
apparatus throughout the healing process. Such visualization will allow 
readjustment of the apparatus if necessary as the fracture heals and as 
the patient uses the associated muscles, tendons, and joints to prevent 
atrophy and stiffness. 
A further advantage of the present invention is to provide a smaller 
fixation clamp, and therefore, a smaller apparatus for patient 
convenience, for encouragement in use of associated muscles, tendons, and 
joints to prevent atrophy and stiffness, and for minimization of secondary 
trauma that could result in disruption of bone union. 
Accordingly, the present solves the prolbems which existed with the other 
external fixator described above in the ability to allow x-ray 
verification of bone alignment during surgery. In addition, the present 
invention also solves the problems which existed with the other external 
fixator described above in the ability to achieve rotational stability of 
the pins.

DISCUSSION OF THE PREFERRED EMBODIMENTS 
The following discussion of the preferred embodiment of the present 
invention is merely exemplary in nature. Accordingly, the discussion is in 
no way intended to limit the scope of the invention, the application of 
the invention, or the use of the invention. 
Referring to FIG. 1, an apparatus 10 for fixation of a bone 12 of the 
distal forearm, hand, and wrist after fracture is shown. The apparatus 10 
may be used for stabilizing a fracture of the distal radius, including 
those known as Colles' fracture. In particular, the apparatus 10 may be 
used for percutaneous internal intramedullary stabilization and external 
fixation of a fracture of the distal radius. As will be appreciated by 
those skilled in the art, the apparatus 10 may be used in a variety of 
orthopedic procedures. In particular, the apparatus 10 may be used in 
procedures where it is desirable to securely fixate adjacent portions of 
bone. 
The apparatus 10 according to the preferred embodiment will now be 
described in further detail with reference to FIG. 2. To provide stability 
through percutaneous internal intramedullary fixation, the apparatus 10 
includes two elongated members 14 and 16. The first elongated member 14 is 
operable to be at least partially inserted into the first and second 
portions of fractured bone 12, while the second elongated member 16 is 
also operable to be at least partially inserted into the first and second 
portions of fractured bone 12. Each of the elongated members 14 and 16 has 
an abrasive surface 18. The abrasive surface is operable to resist 
relative rotation between each of the elongated members 14 and 16 and a 
means for securing the first elongated member to the second elongated 
member discussed below. The abrasive surfaces 18 on each of the elongated 
members 14 and 16 are formed by a 30 grit blast, though other suitable 
methods may be used for forming the abrasive surfaces. Each of the 
elongated members 14 and 16 has a tapered portion 20 for insertion into 
the fractured bone portions for intramedullary fixation of the bone 
portions, as well as an untapered portion 22 for stabilization of the 
portions of the elongated members 14 and 16 external to the skin. A 
low-speed, high-torque power drill may be used to prepare holes in the 
bone for insertion of the elongation members 14 and 16. 
The first and second elongated members 14 and 16 are each initially formed 
(i.e., before being bent in the manner shown in FIGS. 1-7) from a wire 
which is approximately 12.5 inches in length and which has an end portion 
with a taper of approximately 2 degrees from horizontal. However, a wire 
having shorter lengths may also be used to form the first and second 
elongated members 14 and 16. In addition, the tapered portion 20 of the 
first and second elongated members 14 and 16 is also approximately 0.078" 
in diameter and has a radius on the tip of approximately 0.015 radians. 
Finally, when viewed in a manner similar to that shown in FIG. 3 and 4, 
the tapered portion 20 has peripheral portions which converge at an angle 
of approximately 60 degrees. The untapered portion 22 of the first and 
second elongated members 14 and 16 extends laterally approximately 0.8" 
from the tapered portion 20 and then vertically by approximately 1.0". The 
untapered portion 22 then extends again laterally approximately 2.5". The 
first and second elongated members 14 and 16 are preferably formed from 
316 LBM stainless steel, though other suitable materials may be used. 
To provide means for securing the first elongated member 14 to the second 
elongated member 16 and to provide stability of the reduced fractured bone 
12, the apparatus 10 further includes a fixation clamp 24. The fixation 
clamp 24 may include an upper locking member 26 with parallel angled 
grooves 28 for containing portions of the elongated members 14 and 16 
external to the skin. In addition, the fixation clamp 24 may also include 
a lower locking member 30 also with parallel angled grooves 32 for 
containing portions of the elongated members 14 and 16 external to the 
skin. One of the elongated members 14 and 16 may be held within one of the 
parallel angled grooves 28 and 32 and the other of the elongated members 
14 and 16 may be held within the other of the parallel angled grooves 28 
and 32 on each of the locking members 26 and 30. That is, the upper and 
lower locking members 26 and 30 may be placed so that the elongated 
members 14 and 16 lie between the locking members 26 and 30, each within 
its angled groove. The upper and lower locking members 26 and 30 are 
preferably 0.6" in width, 1.56" in height and 0.18" in thickness. In 
addition, while the upper and lower locking members 26 and 30 are 
preferably made from the polyetherimide resin ULTEM, other suitable 
materials may be used. 
The fixation clamp 24 may also include a screw 34 for compressing the upper 
locking member 26 against the lower locking member 30 as the screw is 
turned. The upper and lower locking members 26 and 30 may contain a 
central cylindrical aperture (not shown) with threads (not shown) for 
receiving the screw 34. By causing the upper and lower locking members 26 
and 30 to be compressed against one another with the external portions of 
the elongated members 14 and 16 held between the locking members 26 and 
30, the elongated members 14 and 16 are securely anchored and the bone 12 
is externally fixed in place. The screw 34 includes an aperture 36 for 
receiving a hex-headed wrench which may be used to rotate the screw. 
The head of the screw 34 is preferably sufficiently wide so as to locate a 
portion of the head of the screw 34 directly above the untapered portions 
22 which are located within the grooves 28 and 32. By locating the head of 
the screw 34 in this manner, the portions of the locking members 26 and 30 
directly between the head of the screw 34 and the untapered portions 22 of 
the first and second elongated members 14 and 16 are only in compression. 
That is, there is substantially no moment arm extending between the head 
of a screw 34 and the untapered portions 22 of the first and second 
elongated members 14 and 16. Since there is substantially no moment arm 
between the head of the screw 34 and the untapered portions 22, there is 
less risk of cracking the Ultem which forms the upper and lower locking 
members 26 and 30 during usage of the apparatus 10. 
In addition, the head of the screw 34 is preferably formed from 6061 
aluminum and is relatively thin (i.e., preferably approximately 2 
millimeters). Because relatively thin aluminum is radiolucent, a surgeon 
is able to view the fracture through the head of the screw 34. It will be 
appreciated, however, that other suitable materials may be used to form 
the screw 34 which are radiolucent at relatively small thicknesses. 
The apparatus 10 is preferably inserted into the bone 12 so as to be 
located in the manner shown in FIG. 1. In this regard, it will be noted 
that each of the elongated members 14 and 16 are inserted in the bone 12 
such that there is three point fixation. That is, each end of the 
elongated members 14 and 16 are adjacent to calcar bone. In addition, the 
middle portion of the first and second elongated members 14 and 16 are 
located on a region of the calcar bone which is on the opposite side of 
the bone from where the corresponding ends reside as shown in FIG. 1. By 
inserting the first and second elongated members 14 and 16 in this manner, 
there is an enhanced resistance to having the portions of the bone 12 
separate while the apparatus 10 has been implanted. 
Those skilled in the art can now appreciate from the foregoing that the 
broad teachings of the present invention can be implemented in a variety 
of forms. Therefore, while the invention was described in connection with 
particular examples hereof, the true scope of the invention should not be 
so limited. For example, the present invention may be used with a variety 
of surgical procedures which may not necessarily involve orthopedic 
procedures. In addition, the components of device do not necessarily have 
to be identical to the configuration shown in FIG. 1, but may be of other 
shapes which are desirable for a particular application. Other 
modifications will become apparent to those skilled in the art.