Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
1999-10-29
2001-02-20
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C606S088000, C606S054000
Reexamination Certificate
active
06190390
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to corrective knee structuring and pertains, more specifically, to apparatus and method for the surgical realignment of the knee through proximal tibial osteotomy.
The surgical management of conditions which result in knee misalignment, one of the most common of which is medial compartment osteoarthritis in the varus knee, includes total knee replacement, unicondylar knee replacement, and proximal tibial osteotomy. While each of these options may be appropriate in particular circumstances, it is preferable, especially in younger patients, to avoid implants and to opt for the less radical procedure of high tibial osteotomy. The most common technique for accomplishing the correction of knee misalignment through high tibial osteotomy currently is wedge osteotomy.
However, problems associated with wedge osteotomy render the procedure difficult to perform, lead to both short-term and long-term complications, and discourage both surgeons and patients from choosing the operation. Wedge osteotomy requires meticulous preoperative calculations and is a technically difficult operation. If the wedge osteotomy is not performed perfectly, a variety of problems can occur. Thus, over-correction and under-correction have been identified as common causes of poor results. Even with ideal correction at the time of surgery, alignment can change with time. Wedge osteotomy creates a mismatch between the bony surfaces of the osteotomy. The proximal side of the wedge is larger in surface area and is composed of primarily softer, cancellous bone, and a thinner metaphyseal cortex, while the distal side has a smaller area, thicker cortices, and less cancellous bone. Such a mismatch creates an abrupt lateral wall and increases the potential for long-term drift. Closing a wedge osteotomy creates other anatomic distortions such as lateral joint line deficiencies, distal joint lines, medial collateral ligament abnormalities, lateral ligament abnormalities, posterior cruciate ligament shortening, and patella infera.
Hence, while proximal realignment is considered to be the procedure of choice for younger patients, and especially those patients with medial compartmental osteoarthritis and varus knees, the early and late complications associated with wedge osteotomy have led many surgeons to avoid proximal tibial osteotomy altogether; however, others have sought alternative methods for achieving a reliable realignment through high tibial osteotomy. Among the most promising of these alternatives is dome osteotomy of the proximal tibia. Dome osteotomy demonstrates significant advantages over wedge osteotomy. Thus, because correction is achieved through a dome, rather than a wedge, there is no significant bone loss and anatomy is preserved. Accurate correction is attained more easily since change can be accomplished intraoperatively, in accordance with the surgeon's judgment, and can be verified in the operating room. The operation is accomplished through an anterior incision, avoiding complications associated with the lateral incision required in wedge osteotomy. The dome osteotomy does not create a significant mismatch between the proximal and distal fragments of the osteotomy. In fact, the relatively large surface area between the fragments promotes early and reliable healing. Since correction is achieved through a dome, both varus and valgus corrections are available. However, to be effective, dome osteotomy requires the reliable creation of an appropriate accurate dome.
SUMMARY OF THE INVENTION
The present invention addresses the creation of an effective dome for dome tibial osteotomy. As such, the present invention attains several objects and advantages, some of which are summarized as follows: Facilitates the accurate creation of a dome osteotomy in a proximal tibia osteotomy for the correction of knee misalignment; assures accuracy in the location and orientation of the dome, as well as in the contour of the dome itself; enables correction of knee misalignment with minimal bone loss in a high tibia osteotomy; allows intraoperative adjustments to attain accurate corrections in accordance with the judgment of the surgeon during the procedure; enables varus or valgus corrections; simplifies the procedure for attaining an accurate dome configuration and orientation; provides increased control for creating a more precise and reliable osteotomy with relative ease and with greater safety; enables the creation of a reliable dome osteotomy more quickly, thereby shortening the duration of the procedure; allows the accomplishment of a precise high tibia osteotomy utilizing an anterior incision and minimal invasiveness; promotes early and reliable healing; provides a reliable alternative to total knee replacement without adversely affecting the ability of the site to receive a total knee replacement, should such a replacement become necessary in the future; reduces the chances for complications experienced in connection with corrections attempted by employing a wedge osteotomy; provides instruments of simplified construction capable of ready use with procedures of minimal complexity for the attainment of exemplary results.
The above objects and advantages, as well as further objects and advantages, are attained by the present invention which may be described briefly as an instrument system for creating a dome osteotomy at a selected location on a proximal tibia, the dome osteotomy having a semi-cylindrical surface contour configuration with an arcuate profile configuration placed at the selected location, the instrument system comprising: a first guide component having a longitudinal length, a lateral width, an altitudinal thickness, and a plurality of apertures extending altitudinally through the first guide component and placed along an arc which follows the arcuate profile configuration of the dome osteotomy, the apertures being aligned essentially parallel to one another and including corresponding central axes extending altitudinally, essentially parallel to one another; a plurality of cannulas, each cannula of the plurality of cannulas having a length greater than the altitudinal thickness of the first guide component, an inside guide surface for receiving a complementary drill and an outside guide surface complementary to a corresponding one of the plurality of apertures for being received within the one aperture for guiding the complementary drill along a drill path aligned with the corresponding central axis of the one aperture; and a first guide component affixation arrangement for affixing the first guide component to the proximal tibia with the arc of the plurality of apertures placed in juxtaposition with the selected location of the arcuate profile configuration; the length of each cannula being great enough to assure that each drill path is located in an array of essentially parallel drill paths, with the array creating a pattern for the surface contour configuration of the dome osteotomy located at the selected location on the proximal tibia.
Further, the present invention includes an osteotome for use in an instrument system for creating a dome osteotomy at a selected location on a proximal tibia, the dome osteotomy having a semi-cylindrical surface contour configuration with an arcuate profile configuration placed at the selected location, the instrument system including a guide component having a slot extending along an arc which follows the arcuate profile configuration of the dome osteotomy, the osteotome having: a longitudinal length for extending through the slot; a lateral curved configuration complementary to the arc of the slot for reception within the slot; and a cutting edge extending along the lateral curved configuration for creating the semi-cylindrical surface contour configuration of the dome osteotomy along the arcuate profile configuration as the osteotome is guided by the slot.
Additionally, the present invention provides an improvement in a method for creating a dome osteotomy at a selected location on a prox
Howmedica Osteonics Corp.
Jacob Arthur
Philogene Pedro
LandOfFree
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