1. Field of the Invention
This invention relates generally to orthopedic devices for installation in surgical procedures to position and maintain in opposing ends of a bone together during healing.
2. Prior Art
Maintaining together bone ends of cancellous/cortical bones during a bone knitting or healing process has, in the past, presented a myriad of problems to a treating podiatrist or orthopedist. Particularly, where the bone repair is undertaken on a small bone, such as a broken finger or toe bone that, such have involved a procedure that includes drilling with a K wire, or the like, from a joint through the broken ends, and through the finger or toe end. Which K wire remains in place during bone healing, and is then removed in a second procedure. Like such K wire technique, fixation pins, have been utilized in a fixation of mallet fingers, shaft fracture, and epiphyseal separation, and are installed through the digit end to pass through the joint or fracture.
Where a use of fixation pins and devices for drawing broken bone sections of large bones are common, and examples of such are shown in patents to Lundholm, U.S. Pat. Nos. 2,570,465; to Cochran, et al, 3,103,926; and to Freedland, 4,409,974, with small diameter bones, such arrangements are not practical. Also, for bone fixation, additional to the K wire and fixation pins discussed above, a number of draw pins, bars and staples have been developed. Some examples of draw pin and splint arrangements are shown in patents to Reese, U.S. Pat. Nos. 4,688,561 and to Cox, 3,744,488. Draw bar apparatus for mounting to the bone side to pull broken bone ends together, are shown in patents to Sutter, et al, U.S. Pat. Nos. 4,388,921; to Wu, 4,570,624; and to McKinney, 5,167,665. Additionally, staple devices, including an adjustable staple, are shown in patents to Medico, U.S. Pat. Nos. 4,913,144 and to Gilmer, Jr., 4,723,540; and a variety of staple devices are shown in patents to Shapiro, U.S. Pat. Nos. 4,414,967; to Borzone, 4,278,091; to Pratt, et al, 4,438,769; to Crainich, 4,607,638; to Gauthier, 4,838,254; and to Sheehan, 5,053,038. None of which devices, however, is like the present invention that provides individual couplings that are for mounting, respectively, in the bone opposing faces to align with one another and snap together. Which device tightly couple and maintain the bone ends together during the bone healing or knitting process.
The above cited patents illustrate earlier devices that employ structures and procedures either for fitting a pin, or the like, from a joint to a bone end for pulling bone pieces together; provide for fitting a pin device across broken bone ends; or provide for installing a staple or draw bar arrangement, or combination thereof, onto a bone exterior to pull broken bone opposing end faces together. Such earlier devices and procedures as involve longitudinal or lateral pinning are highly invasive, and staple and draw bar devices are often impractical for use with small bones. The present invention, unique therefrom, provides a procedure that is minimally invasive in that it provides for turning coupling members into opposing faces of a broken bone that are arranged to snap together for both maintaining bone end faces in alignment and to maintain a minimum contact pressure therebetween so as to promote the bone ends or sections knitting or healing together. The individual couplings members preferably each include a section of threads formed therealong for turning into the bone material and individually include male and female coupling ends that extend, respectively, from the bone opposing end faces for joining together.
To provide for turning into bone ends, the members either are for turning into pre-drilled holes or each employs a trust drill that extends axially from a forward member end with a threaded mid-section, and with a male or female coupling extending axially from a rear end. Which drill end and threaded mid-section are similar to an anchor device shown in a prior patent of one of the inventors identified as, a "Suture Anchor Assembly", U.S. Pat. No. 4,632,100, which device is shown utilized in later U.S. Pat. Nos. 4,927,421 and 5,037,426. The devices, of these patents, however, show arrangements for anchoring a suture, or the like, onto a bone surface, and are shown for use as an interference screw, rather than a bone fixation system that includes interactive coupling ends for joining and maintaining bone ends faces and systems together in proper alignment so as to a minimum resistive force to separation of which bone surfaces.