Joint replacement surgery is a common orthopedic procedure to repair and replace a damaged, diseased, or otherwise unhealthy joint. These procedures generally fall into two categories: primary and revision. In a primary joint replacement, the operator replaces the native joint with prosthetic components typically by first resecting the native bone and/or cartilage and then affixing the prosthetic components to the resected bone.
A revision procedure is performed to replace the primary prosthesis, or in some instances, a previously implanted revision prosthesis. Typically, during a revision procedure, the previously implanted prosthesis is extracted and the underlying bone resurfaced in preparation for receipt of the revision prosthesis. Bone defects in the form of bone loss or deterioration are frequently exposed upon extraction of the previously implanted prosthesis. These defects often reside within the epiphyseal and metaphyseal regions of the bone and extend radially outwardly from the center of the bone. Such defects may be caused by, inter alia, osteolysis, necrosis, infection, and bone incidentally removed along with the previously implanted prosthesis. In order to account for such defects, numerous void filling implants, such as that disclosed in Noiles U.S. Pat. No. 4,846,839, for example, have been developed to fill the voids formed by these defects and to provide structural support for the bone and prosthesis.
Despite the benefits of these void filling implants, their use in complex revision procedures may further complicate the procedure. Prior to extraction of a previously implanted prosthesis, the joint must be exposed. In an example of a total knee replacement, exposure can be made difficult for a number of reasons, such as an exceptionally tight extensor mechanism, which may be due to an improperly fitted prosthesis. One technique for exposing difficult-to-expose knees is a tibial tubercle osteotomy in which the patella tendon is released from the tibia by resecting the bone surrounding the tibial tubercle, which is later resecured to the tibia by at least one fixation device, such as a bone screw or cerclage wire, for example. However, the presence of a void filler, or even an intramedullary stem, creates an obstacle for the fixation device that must be navigated, oftentimes blind, resulting in increased complication of the procedure.
In another example, a patient may suffer an extensor mechanism complication, such as patellar tendon rupture, that must be repaired during the revision procedure. The ruptured tendon may be repaired by an allograft technique where a bone plug with an attached tendon is secured to the tibia also by a fixation device. Again the presence of a void filler or intramedullary stem may interfere with such a repair.
Therefore there is a need for a void filling prosthesis that facilitates bone-to-bone fixation and tissue-to-bone fixation.
USPTO Backgrounds
USPTO Backgrounds