162 results about "Knee replacement" patented technology

Disclosed herein are methods and devices for repairing articular surfaces in a knee joint. The articular surface repairs are customizable or highly selectable for each patient and geared toward providing optimal fit and function. Kits are also provided to enable customized repairs to be performed.

Novel cutting guides and surgical methods for use in knee arthroplasty are described. Embodiments of the inventive cutting guide apparatus include fixed and adjustable cutting guide blocks having a series of slots designed to accommodate a cutting saw. The cutting guides and surgical method are designed to allow for the provision of all desired surgical cuts upon the distal end of the femur, for subsequent implantation of a prosthesis thereto, without having to remove the cutting guide block.

The invention is a method for performing a minimally invasive knee arthroplasty and components for this procedure. The method involves creating an incision along the medial or lateral aspect of a patient's knee, exposing the knee joint, resecting the distal end of the femur, the proximal end of the tibia and the posterior patella through the medial or lateral incision, and connecting a femoral, tibial and patellar knee replacement component through the incision. Components include specialized femoral, tibial and patellar cutting guides for use in resecting the femur, tibia and patella through the medial or lateral incision. In one embodiment, the method is performed with the aid of an image guidance system. In another embodiment, the method is performed with instruments which align the components, such as the cutting guides, without the use of an image guidance system.

There is provided a method and system for determining a distal cut thickness and posterior cut thickness for a femur in a knee replacement operation, the method comprising: performing a tibial cut on a tibia; performing soft tissue balancing based on a desired limb alignment; measuring an extension gap between the femur and said tibial cut while in extension; measuring a flexion gap between the femur and the tibial cut while in flexion; calculating a distal cut thickness and a posterior cut thickness for the femur using the extension gap and the flexion gap and taking into account a distal thickness and posterior thickness of a femoral implant; and performing said femoral cut according to the distal cut thickness and posterior cut thickness.

An inertial sensor based surgical navigation system for knee replacement surgery is disclosed. Inertial sensors composed of six-degree-of-freedom inertial chips, whose measurements are processed through a series of integration, quaternion, and kalman filter algorithms, are used to track the position and orientation of bones and surgical instruments. The system registers anatomically significant geometry, calculates joint centers and the mechanical axis of the knee, develops a visualization of the lower extremity that moves in real time, assists in the intra-operative planning of surgical cuts, determines the optimal cutting planes for cut guides and the optimal prosthesis position and orientation, and finally navigates the cut guides and the prosthesis to their optimal positions and orientations using a graphical user interface.

A knee replacement system provides a knee implant that may be used to more accurately replicate the diameter of a natural knee. In one embodiment, a patellofemoral component is connected to the posterior portion of a condylar component by screws that pass through the femur allowing the patellofemoral component and the condylar component to be torqued against opposing sides of the femur. Two additional screws are used to connect the patellofemoral component to an anterior portion of the condylar component. A gap may be left between the patellofemoral component and the anterior portion of the condylar component if needed to provide precise replication of the diameter of the natural knee from the patellofemoral component to the condylar component.

A knee replacement system provides a knee implant that may be used to more accurately replicate the diameter of a natural knee. In one embodiment, a patellofemoral component is connected to the posterior portion of a condylar component by screws that pass through the femur allowing the patellofemoral component and the condylar component to be torqued against opposing sides of the femur. Two additional screws are used to connect the patellofemoral component to an anterior portion of the condylar component. A gap may be left between the patellofemoral component and the anterior portion of the condylar component if needed to provide precise replication of the diameter of the natural knee from the patellofemoral component to the condylar component.

A method and apparatus for knee replacement surgery wherein a femoral provisional component is provided which corresponds to a permanent component to be implanted in a human and which includes means for establishing the correct fit and position of such a component, prior to its implantation, in relation to the soft tissues of the knee before final resection of the anterior femoral surface. The provisional component further includes cutting guide means for such anterior surface resection such that accurate cuts may be made with the provisional component in place. The method involves preparing the distal femoral surface using the femoral intramedullary canal as a constant reference point for posterior and distal cutting guides followed by locating the provisional component by means of a provisional intramedullary stem so that the relationship with the soft tissues of the knee may be accurately established.

An artificial knee joint that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces. The interaction provides for the required motion and stability characteristics. The interaction between the femoral and tibial surfaces is such that as the knee is flexed to maximum, the femoral component moves posteriorly on the tibial surface, by an amount similar to that in the anatomic knee. This is accomplished primarily by the depth and width of the femoral trochlea diminishing as the femoral component is flexed from zero to maximum, together with a ramp on the center of the tibial surface. The opposite motion, roll forward of the femur from a fully flexed to a more extended position, is accomplished by varying the outward radii of the lateral and medial femoral bearing surfaces, together with a ramp on the postero-lateral and postero-medial regions of the tibial surfaces. A variation of this is to generate a tibial surface which provides for a progressive internal rotation of the tibia as flexion proceeds.

A method is provided for performing knee replacement surgery on a leg of a patient. The method includes making a cut on a posterior portion of a patella, making a cut on a proximal portion of a tibia, and making a cut on the distal portion of the femur. The cut on the patella is performed before making the cuts on the tibia and femur.

A system and method for measuring biomechanical parameters of a knee prior to total knee replacement (TKR) surgery includes a plurality of microsensors removably attached to the femur, tibia and patella; at least one sensor communicating with the plurality of microsensors; a navigation system coupled to the at least one sensor; an imaging system coupled to the navigation system for performing imaging of the joint; and at least one display for displaying imaging and tracking data.

A knee replacement system includes a proximal tibial posterior camming portion defined by a first radius of curvature with a first origin in a first medio-lateral plane, a distal tibial posterior camming portion defined by a second radius of curvature with a second origin in a second medio-lateral plane, an anterior femoral camming portion of a posterior cam defined by a third radius of curvature with a third origin in the first medio-lateral plane, and a posterior femoral camming portion of the posterior cam and defined by a fourth radius of curvature with a fourth origin in the second medio-lateral plane, wherein the second origin is closer to the lateral tibial portion than the first origin, or the fourth origin is closer to the medial femoral portion than the third origin.

A knee replacement prosthesis comprising a femoral component and a tibial component that enable anterior-posterior translation of the femur relative to the tibia and enable the tibia to rotate about its longitudinal axis during flexion of the knee. The femoral component connects to the distal end of a resected femur and includes medial and lateral condyles having distal, articulating surfaces, and a patellar flange having a patellar articulating surface. The tibial component connects to the proximal end of a resected tibia and includes a proximal bearing surface with medial and lateral concavities that articulate with the medial and lateral condyles. The articulating surfaces of the condyles and concavities are defined by sections of toroids.

A patellar trial and drill guide for use during knee replacement surgery comprising an articular surface member and a fixation peg drill guide. The articular surface member is the exact geometry as the artificial patellar implant, and the drill guide aligns the holes for the fixation pegs of the artificial patellar implant. The patellar trial is placed on the resected patella in the desired position, a patellar clamp is used to temporary fix the patellar trial to the patella. The patella is then returned to its normal position and a trial reduction of the total knee replacement is completed. If the placement and / or size of the patellar trial is unacceptable, the patella is inverted, the patellar trial removed, and a different sized trial or new location is determined. The new patellar trial is secured to the resected patella, and another trial reduction of the total knee replacement is completed. This procedure can be repeated until the patellar trial is the correct size and in the proper location. If the placement of the patella is acceptable, the patella is inverted, the articular surface member removed, fixation peg holes are drilled using the fixation peg holes of the drill guide, and an artificial patellar implant is implanted on the patient's remaining patella.

An artificial knee joint that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces. The interaction provides for the motion and stability characteristics of the anatomic knee. The interaction between the femoral and tibial surfaces is such that as the knee is flexed to maximum, the femoral component moves posteriorly on the tibial surface, more so on the lateral side than on the medial side. This is accomplished by the interaction of a projecting tibial post inside a cupola in the center of the femoral component, and by the saggital radius on the medial side being smaller than that on the lateral side. The prevention of anterior sliding of the femur on the tibia in early flexion is accomplished by the interaction between a distal-anterior recess on the medial side of the femur and an apposing raised pad on the tibial surface. Rotational laxity at all angles is allowed by the presence of only one recess pad and by non-conforming femoral-tibial surfaces on the lateral side.

There is disclosed a total knee replacement prosthesis, which can substitute the function of an anterior and / or a posterior cruciate ligament. A femoral component containing two intercondylar surfaces and an intercondylar region, a tibial component having a tibial platform and a bearing component, and a protrusion from the bearing component also are disclosed.

The invention relates to surgical instruments, a computer program element which provides control or information relating to the surgical instruments, a computer program providing the same, a computer readable medium comprising the computer program, a method for implementing a computer-aided means of guiding a surgeon through a desired surgical procedure and to a computer aided surgical procedure. In a preferred embodiment, the invention relates to instruments, a computer program element, computer programs, a computer readable medium and methods for use in knee replacement operations.

Methods and systems are described to quantitatively determine the degree of soft tissue constraints on knee ligaments and for properly determining placement parameters for prosthetic components in knee replacement surgery that will minimize strain on the ligaments. In one aspect, a passive kinetic manipulation technique is used in conjunction with a computer aided surgery (CAS) system to accurately and precisely determine the length and attachment sites of ligaments. These manipulations are performed after an initial tibial cut and prior to any other cuts or to placement of any prosthetic component. In a second aspect, a mathematical model of knee kinematics is used with the CAS system to determine optimal placement parameters for the femoral and tibial components of the prosthetic device that minimizes strain on the ligaments.

A knee replacement system includes a femoral component including a lateral condylar articulating portion and a medial condylar articulating portion, a tibial tray including an upper articulating surface, and a tibial insert including (i) a first articulating portion for articulating with the lateral condylar articulating portion with a first condylar dwell point, (ii) a second articulating portion for articulating with the medial condylar articulating portion with a second condylar dwell point, (iii) a lower articulating surface for articulating with the upper articulating surface, and (iv) a coupling member for coupling with the tibial tray and defining an axis of rotation about which the tibial insert rotates with respect to the tibial tray, the axis of rotation intersecting the upper articulating surface at a location posterior to a dwell axis including the condylar dwell points when the dwell axis is projected onto the upper articulating surface.

An apparatus for resecting a distal femoral condyle includes a resection guide defining a first bone fixation aperture extending about an axis. The resection guide further defines a first bone saw slot and a second bone saw slot. The resection guide is configured to position the first bone fixation aperture relative to the condyle. The resection guide is further configured to concurrently arcuately translate the first bone saw slot and the second bone saw slot relative to the axis. A knee replacement kit includes a femoral implant defining a first plan contour. The kit further includes a resection guide defining a second plan contour modeling the first plan contour.

An assembly for guiding resection of a femur and tibia of a knee joint in preparation for installing a femoral and tibial knee components. For example, the assembly can include tibial and femoral IM rods to which are connected through a torque bolt that allows controlled adjustment of the distraction of the tibia and femur during cut positioning in a range of flexion angles. Also, the assembly is usable with relatively small, noninvasive approaches to the knee joint by way of relatively narrow, low profile components that attach to tibial and femoral IM rods. Further, the assembly includes several quick-release components to allow fast assembly and disassembly in a surgical setting. Each of these aspects, along with the ability of the assembly to accurately guide initial reference cuts to the tibia and femur, promotes an improved outcome for the patient.

Apparatus and surgical techniques provide alternative cutting fixtures and other features to improve bone resection accuracy and joint stability. According to one embodiment, stabilizers are removably attached to a cutting guide to temporarily lengthen the surface against which a saw or other cutting device rests. Another embodiment provides differently shaped saw blades, having curved distal ends and right-angle bends applicable to box cuts of the type associated with cruciate sacrifice knee-replacement surgery. Methods are also disclosed whereby the box cuts, distal and posterior augment cuts may be approached from a distal perspective, both laterally and medially. A different embodiment provides a trial / cutting guide having flat surfaces as opposed to curved surfaces adapted for articulation within a joint. Yet a further alternative embodiment teaches a device for determining the joint line relative to a tibia using the fibula as reference.

An assembly for guiding resection of a femur and tibia of a knee joint in preparation for installing a femoral and tibial knee components. For example, the assembly can include tibial and femoral IM rods to which are connected through a tensioning bolt that allows controlled adjustment of the distraction of the tibia and femur during cut positioning in a range of flexion angles. Also, the assembly is usable with relatively small, noninvasive approaches to the knee joint by way of relatively narrow, low profile components that attach to tibial and femoral IM rods. Further, the assembly includes several quick-release components to allow fast assembly and disassembly in a surgical setting. Each of these aspects, along with the ability of the assembly to accurately guide initial reference cuts to the tibia and femur, promotes an improved outcome for the patient.

Apparatus and surgical techniques provide alternative cutting fixtures and other features to improve bone resection accuracy and joint stability. According to one embodiment, stabilizers are removably attached to a cutting guide to temporarily lengthen the surface against which a saw or other cutting device rests. Another embodiment provides differently shaped saw blades, having curved distal ends and right-angle bends applicable to box cuts of the type associated with cruciate sacrifice knee-replacement surgery. Methods are also disclosed whereby the box cuts, distal and posterior augment cuts may be approached from a distal perspective, both laterally and medially. A different embodiment provides a trial / cutting guide having flat surfaces as opposed to curved surfaces adapted for articulation within a joint. Yet a further alternative embodiment teaches a device for determining the joint line relative to a tibia using the fibula as reference.

The present invention relates to a femoral component for use in connection with knee anthroplasty. The implant includes a support having a contoured inner bone engaging surface, and a shell affixed to the support. The shell has an outer surface spaced so as to provide an articulation surface for engaging the tibia that substantially replicates the shape of a femoral condyle, and an inner surface for receiving an outer surface of the support. The support bone engaging surface is structured to mate with a prepared surface of the distal femur and the support spaces the shell outer surface at a predetermined distance from the prepared surface.

Systems, devices, and methods are provided for measuring forces in the space of a knee during surgery. Such forces can be caused by tension in the ligaments of the knee. A femoral member is engaged with a distal femur. While the knee is flexed, partially extended, or fully extended, a force sensor and a gauge shim can be placed in the gap between the femoral member and the tibial plateau to measure the forces therebetween. The force sensor provides an accurate and quantifiable measurement of force, making knee replacement surgery and ligament tension balancing more accurate, standardized and repeatable. The force sensor comprises an elongate housing which comprises a thin force sensing distal portion and a proximal handle portion.

This patent describes a device to replace the proximal femoral head and neck. The uniqueness of the device is in its proximal design which incorporates a transverse tension bar which prevents failure of the femoral neck portion of the device in tension. This design characteristic permits the use of thinner materials which more closely resemble the elastic nature of bone itself while at the same time endowing the prosthesis with strength and resistance to failure. The device is designed to have a long intramedullary portion which would load the femur throughout its length as well as a modular attachment on its distal end for the insertion of a future knee replacement.

Techniques and instruments for knee replacement surgery that allow for the removal of an oval oblong-shaped allograft bone and cartilage plug from a donor distal femur. The instruments include (i) sizing guides to match the recipient's femoral size and curvature to that of a donor femur (the sizing guides also acting as a wide pin placement template for the donor distal femur); (ii) osteotomes that cut the curved and straight portions of the implant shape (these may be disposable or reusable); and (iii) templates that fit over the guide pins and have openings to allow the osteotomes to cut the donor femur plug to the correct size, shape and depth. The instruments allow for a non-circular shape to be extracted from a donor femur for use in a bone-saving osteoarthritis distal femur resurfacing procedure.