119 results about "Knee surface" patented technology

A patellar 3-D guidance tool includes a template. The template includes at least one contact surface for engaging a surface of the patella. The at least one contact surface substantially conforms with the surface associated with the patellar. At least one guide aperture directs movement of a surgical instrument, wherein the shape and / or position of the guide aperture is based, at least in part, on three or more anatomic reference points associated with the patellar.

A replacement device for resurfacing a joint surface of a femur and a method of making and installing such a device is provided. The custom replacement device is designed to substantially fit the trochlear groove surface, of an individual femur. Thereby creating a "customized" replacement device for that individual femur and maintaining the original kinematics of the joint. The replacement device may be defined by four boundary points, and a first and a second surface. The first of four points is 3 to 5 mm from the point of attachment of the anterior cruciate ligament to the femur. The second point is near the bottom edge of the end of the natural articulatar cartilage. The third point is at the top ridge of the right condyle and the fourth point at the top ridge of the left condyle of the femur. The top surface is designed so as to maintain centrally directed tracking of the patella perpendicular to the plane established by the distal end of the femoral condyles and aligned with the center of the femoral head.

A patellar 3-D guidance tool includes a template. The template includes at least one contact surface for engaging a surface of the patella. The at least one contact surface substantially conforms with the surface associated with the patellar. At least one guide aperture directs movement of a surgical instrument, wherein the shape and / or position of the guide aperture is based, at least in part, on three or more anatomic reference points associated with the patellar.

A patellar 3-D guidance tool includes a template. The template includes at least one contact surface for engaging a surface of the patella. The at least one contact surface substantially conforms with the surface associated with the patellar. At least one guide aperture directs movement of a surgical instrument, wherein the shape and / or position of the guide aperture is based, at least in part, on three or more anatomic reference points associated with the patellar.

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.

A two-thirds prosthetic arthroplasty having a trochlear groove, a patello-femoral component, and either a lateral condyle or a medial condyle. The arthroplasty may be configured to be a prosthetic for either a right or left knee. The condyle and patello-femoral component are separated by a modified intercondylar notch that is blended to avoid protrusions or sharp angles. The prosthetic arthroplasty is inserted after preoperative MRI mapping of articular cartilage damage. The prosthetic arthroplasty may be cemented during surgery and the two-thirds design of the present invention obviates the problem of cement retrieval from remote parts of the prosthesis.

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.

Disclosed is a device and method of bicompartmental arthroplasty of the knee. The device permits arthroplasty of the medial or lateral and patellofemoral compartments of the knee while leaving the opposite compartments and the anterior and posterior cruciate ligaments intact. The device provides a femoral prosthesis component that includes a trochlear surface and a tibial prosthesis component which can be secured to the tibia. The femoral component is essentially “u” shaped having an anterior leg upon which the trochlear surface is positioned and a posterior leg which engages the posterior surface of the distal end of the femur. The femoral component also has a convex articulating surface which engages a concave articulating surface of the tibial prosthesis component to approximate the articulation of a healthy knee. The patellar prosthesis is applied to the posterior surface of the patella and articulates with the trochlear exterior surface of the femur.

A patellar implant for total or partial prosthesis of the knee joint incorporates an outer articular surface and an inner articular surface provided to cooperate respectively with an outer side and an inner side of a femoral trochlea or of a femoral prosthetic component. The inner and outer articular surfaces are separated by a transition ridge which is curved, as viewed from a front of the implant, so as to be concave facing the outer articular surface. The outer articular surface is concave in a plane parallel to a sagittal plane and in a transverse plane of the knee joint.

A patellar cutting guide is particularly useful in a method of minimally invasive knee arthroplasty in which an incision is made along the medial or lateral aspect of a patient's knee, exposing the knee joint. The patellar cutting guide includes a clamp configured to be located exterior to the knee over the anterior portion of the patella, a stop having at least one portion configured to extend through an incision to a location posterior to the patella, and a cutting guide defining a cutting slot. The clamp may have outwardly extending spikes for passage through the tissue overlying the patella and into engagement with the patella. The stop is movable relative to the clamp and / or cutting guide. In one embodiment, the cutting guide is offset laterally and posteriorly relative to the clamp so that the slot is aligned with a medially or laterally-formed incision in the knee.

A knee prosthesis comprises a femoral component, a tibial component and a bearing component therebetween. The femoral component defines medial and lateral condylar surfaces which are in the form of respective parts of a common helix, and the bearing component has respective surfaces matching the condylar surfaces. Accordingly a patella groove in the femoral component is laterally displaced, and on flexion of the knee, in use, from an extended position there is a lateral translatory movement of the femur. Congruent contact between the femoral component and the bearing component is maintained through at least 60° of flexion of the knee from an extended position.

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 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 condylar articulating surfaces and the said concavities are substantially defined by non-uniform, rational B-spline surfaces (NURBS).

An apparatus for stabilizing movement of the patella in the patellofemoral joint comprises in one embodiment a base having an opening, a buttress secured to the base sheet member, a tensioning member secured to the base sheet member, a pair of tensioning arms secured to the buttress, a pair of tensioning arms secured to the tensioning member, a pair of compression members formed from the base, and a stabilizing member secured to an edge of the base. A method of stabilizing movement of the patella in the patellofemoral joint during physical activities comprises in one embodiment the steps of positioning a support brace having an opening against the knee, extending a portion of the brace against the knee to apply a first force against portions of the knee in the opening, and extending another portion of the brace against the knee to apply a second force against the knee.

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.

A patellar alignment device for determining the position of a patella prosthesis. The device comprises two components-a baseplate and a mobile component which is preferably magnetically attached to the baseplate. During a surgical procedure to replace the knee, the baseplate is temporarily attached to the back of the patella. The baseplate may contain spikes or prongs to secure it to the patella. The baseplate further includes a series of slots for marking the patella. The mobile component resembles a patella and is placed on the baseplate. The patella with the alignment device in place is then placed in position on the knee and trialed. Because the mobile component is free to move on the baseplate, it finds the position that is most amenable to a natural knee movement. The alignment device is then exposed and the patella is marked at the position of the mobile component. Since the baseplate contains a series of slots, the patella can be easily marked at several locations around the mobile component. The entire patella alignment assembly is then removed and the final prosthetic device can be inserted at the marked location.

Disclosed are improved and / or patient-adapted (e.g., patient-specific and / or patient-engineered) patellar clamp systems, surgical methods and related surgical tools. The various clamp assemblies can facilitate one-handed operation by a user and can include modular features that provide for ease of interchangeability to accommodate components having patient specific features that conform or substantially conform to the patient's patellar anatomy.

Embodiments of the present invention provide patellar component designs that are optimally shaped to help reduce shear force and accommodate slight implantation error. Further, they help lessen anterior knee pain, particularly during deep-flexion activities and help ease the transition during the range of knee movement in a controlled way.

A knee brace is provided having upper and lower arms and a hinge assembly positionable about the knee to one side of the patella. The hinge assembly has a hinge pivot and a tension strap lever. The upper and lower arms and tension strap lever are each rotatable about the hinge pivot. A compression member is positioned in engagement with the knee on the opposite side of the patella from the hinge assembly and a tension strap engages the compression member and is connected to the tension strap lever. The tension strap applies a tension force to the compression member which increases when the upper and lower arms and tension strap lever rotationally transition from a flexion position to an extension position and decreases when the upper and lower arms and tension strap lever rotationally transition from the extension position to the flexion position.

A patellofemoral brace including a buttress for supporting a wearer's patella is provided. The patellofemoral brace includes an elastic sleeve that is easy to apply to the wearer's leg and easy to remove from the wearer's leg. The sleeve includes distinct bands of material so that end bands are substantially rotationally independent of a central band. The end bands resist translation along and rotation about the wearer's leg. The brace further includes a tensioning strap that lies across the buttress to further support the buttress and the wearer's patella. A portion of the tensioning strap is constructed of a thermoplastic elastomer, so that the strap provides firmer support to the buttress than a fabric strap, but is more comfortable and more evenly supports the buttress than a hard, inelastic strap.

A knee orthosis is provided having upper and lower arms and a hinge assembly positionable about the knee to one side of the patella. The hinge assembly has a hinge pivot and a tension strap lever. The upper and lower arms and tension strap lever are each rotatable about the hinge pivot. A compression member is positioned in engagement with the knee on the opposite side of the patella from the hinge assembly and a tension strap is connected to the compression member and the tension strap lever. The tension strap applies a tension force to the compression member which increases when the upper and lower arms and tension strap lever rotationally transition from a flexion position to an extension position and decreases when the upper and lower arms and tension strap lever rotationally transition from the extension position to the flexion position.

Systems and methods for providing deeper knee flexion capabilities, more physiologic load bearing and improved patellar tracking for knee prosthesis patients. Such systems and methods include (i) adding more articular surface to the antero-proximal posterior condyles of a femoral component, including methods to achieve that result, (ii) modifications to the internal geometry of the femoral component and the associated femoral bone cuts with methods of implantation, (iii) asymmetrical tibial components that have an unique articular surface that allows for deeper knee flexion than has previously been available, (iv) asymmetrical femoral condyles that result in more physiologic loading of the joint and improved patellar tracking and (v) modifying an articulation surface of the tibial component to include an articulation feature whereby the articulation pathway of the femoral component is directed or guided by articulation feature.

A patella resection clamp for use in resecting a patella has a first elongated handle portion and a second elongated handle portion. Each of the portions having first and second ends. The two handle portions are pivotally connected at a pivot point intermediate the first and second ends for rotation about a pivot axis. The second end of each of the elongated handle portions include a jaw with the jaw of the first and second handle portions spaced from the second end of the elongated portions in a direction parallel to the pivot axis. The jaws are spaced to form an opening therebetween for receiving the proximal and distal edges of the patella. The jaw portions including a saw blade guide surface or slot open to at least one of the first or second ends of each of said jaw portions. The guide surface or slot is for receiving a saw blade extending under (posteriorly) the handle portions and in a direction perpendicular to the pivot axis and perpendicular to the gripping direction of the jaws.

A knee protector includes a plurality of pads positioned to cover a patella, a lower portion of the distal femur, the femoral condyles, the upper end of the fibula and an upper end of the proximal tibia with spacings between said pads to accommodate the flexion and extension of the knee when in use from a standing to a squatting position by a wearer.

An instrument for implanting patellar prostheses in various sizes includes a series of milling calipers of various sizes, a retaining instrument with a receptacle for one of the milling calipers matching the sizes of the patellar prostheses and milling bodies in various sizes. The retaining instrument is configured like forceps with two members, the front end of one of the members being provided with a retention plate for engagement with a front face of a patellar prosthesis, and the front end of the other one of the members being provided with a holder for a milling gauge.

Instruments and a method for preparing the articular surface of the patella to receive a patellar implant are utilized without everting the patella. A medial or lateral parapatellar incision and an anterior midline incision are made adjacent the patella. The patella is clamped with a patella clamp, a hole is drilled from the anterior surface of the patella. A reamer is inserted through the medial or lateral parapatellar incision and is then attached to the end of a drive shaft that extends outwardly beyond the articular surface of the patella. The posterior facing cutting surface of the reamer device is then placed in contact with the articular surface. The drive shaft is then rotated and moved anteriorly causing the cutting surface of the reamer device to remove a desired amount of patellar cartilage and bone to accommodate a patellar component. The patellar component is secured into place by aligning a central peg protruding from the top surface of the patellar component with the previously drilled hole in the patellar remnant.

The distal end part of the retractor according to the invention is provided both with terminal tips for abutment on one of the femoral condylar walls which define therebetween the intercondylar space, and with a wing extending laterally in projection from this end part in order to form a frontal surface for thrust, in a medial-lateral direction, of that part of the quadriceps muscle tendon containing the patella when the tips are in abutment in the intercondylar space. By using this retractor as a lever, the wing efficiently reclines the patella, without turning it completely on itself, entirely exposing one of the femoral condyles. This invention is more particularly applicable to a surgical procedure for implanting a unicompartmental knee prosthesis.

Systems and methods for providing deeper knee flexion capabilities, more physiologic load bearing and improved patellar tracking for knee prosthesis patients. Such systems and methods include (i) adding more articular surface to the antero-proximal posterior condyles of a femoral component, including methods to achieve that result, (ii) modifications to the internal geometry of the femoral component and the associated femoral bone cuts with methods of implantation, (iii) asymmetrical tibial components that have an unique articular surface that allows for deeper knee flexion than has previously been available and (iv) asymmetrical femoral condyles that result in more physiologic loading of the joint and improved patellar tracking.

A patella femoral brace having a support member configured to be worn about the knee of a user, the support member having an upper portion (10) extending above the knee and a lower portion (12) extending below the knee, and a pressure cuff (32) attachable to the support member in a position to exert force on at least a portion of the periphery of the user's patella. The pressure cuff can have a plurality of connection members (33) for securement to the sleeve (16) at selective ones of a plurality of connection points (25, 26, 27) provided on opposite sides of the knee and above and below the knee, such that the position of the pressure cuff is adjustable by varying connection of the connection members to selective ones of the connection points to apply force to the patella in a plurality of directions. A buttress (24) can be provided between the pressure cuff and the patella.