Abstract: Surgical implants for replacing cartilage are provided with hydrogel polymers affixed to anchors made of “shape-memory” materials, such as nitinol alloys. These implants can be flexed, allowing them to be inserted into joints arthroscopically. After insertion, an implant will return to its manufactured size and shape, and can be anchored to bone or other tissue. The anchoring components can grip and hold hydrogels or other soft polymers by means of an interface of porous fabric. The fabric can support a reinforcing mesh embedded within the soft polymer, and its bottom surface can promote tissue ingrowth, leading to stronger anchoring. Two or more porous layers can enclose a soft polymer, for purposes such as sustained drug release or holding transplanted cells.

Abstract: A semi-permeable membrane can be used to promote the surgical repair of cartilage in a damaged or diseased joint, such as a knee, hip, or shoulder. In one method, the semi-permeable membrane is secured to the “articulating” surface (the exposed surface, as opposed to the “anchoring” surface which rests on a condyle) of a resorbable fibrous matrix that has been seeded, before implantation, with chondrocyte or similar cells that generate cartilage. A membrane used in this manner can help protect the cells as they grow, reproduce, and secrete new cartilage inside the resorbable matrix. In another method, the semi-permeable membrane is secured to a slightly damaged surface of a cartilage segment that is suffering from a condition known as chondromalacia, without using an underlying implanted matrix or other device.

Abstract: Surgical implants use combined anchoring components to replace meniscal or labral cartilage, in ways that provide strong reinforcement while emulating natural anchoring. An arc-shaped polymer segment is coupled to an anchoring rim made of shape-memory material, which will fit into a groove prepared in a bone surface using specialized tools. A fabric material or anchoring ring is provided above the polymer segment, and can be secured to a knee capsule or other soft tissue. Fabric strips can extend out from the tips of the polymer arc, for additional anchoring. An additional polymer segment can also be provided to replace a hyaline cartilage layer, with a porous bottom surface to promote tissue ingrowth. By using peripheral rather than central anchoring, such implants can be given very high strength and stbility, to last for multiple decades.

Abstract: Implants with hydrogel layers reinforced by three-dimensional fiber arrays can replace hyaline cartilage. Such implants should replace an entire cartilage segment, rather than creating a crevice around a plug, so these implants must be thin and flat, they must cover large areas, the tips of any tufts or stitches must not reach the hydrogel surface, and they must be flexible, for arthroscopic insertion. The use of computerized stitching machines to create such arrays enables a redesigned and modified test sample to be made with no delays, and no overhead or startup costs. This provides researchers with improved tools for making and testing implants that will need to go through extensive in vitro, animal, and human testing before they can be approved for sale and use. Fiber-reinforced hydrogels also can be secured to strong shape-memory rims, for securing anchoring to bones.

Abstract: Surgical tools are disclosed for minimally-invasive planing of bone surfaces that will support prosthetic implants, such as cartilage-repair implants. Such planing tools must create smooth surfaces that will closely fit the anchoring surface of an implant. Such tools can use a rotating cylindrical burr, partially covered by a cowl having adjustable components to control grinding depth and bone curvature. Burrs can be mounted on the ends of rotating shafts, or they can be angled, using drive-coupling interfaces. In other embodiments, shaver or burr tools can be supplemented by accessory-type devices (such as suction tubes, cautery tips, and pinchers) that can be extended beyond the normal working tip of a tool, to enable additional functions that will be useful during surgery.

Abstract: Hydrogel devices for surgical implantation to replace damaged cartilage in a mammalian joint (such as a knee, hip, shoulder, etc.) are disclosed, with one or more of the following enhancements: (1) articulating surfaces that have been given negative surface charge densities that emulate natural cartilage and that interact with positively charged components of synovial fluid; (2) anchoring systems with affixed pegs that will lock into accommodating receptacles, which will be anchored into hard bone before the implant is inserted into a joint; (3) a three-dimensional reinforcing mesh made of strong but flexible fibers, embedded within at least a portion of the hydrogel.

Abstract: A permanent non-resorbable implant allows surgical replacement of cartilage in articulating joints, using a hydrogel material (such as a synthetic polyacrylonitrile polymer) reinforced by a flexible fibrous matrix. Articulating hydrogel surface(s) are chemically treated to provide a negative electrical charge that emulates the negative charge of natural cartilage, and also can be treated with halogenating, cross-linking, or other chemical agents for greater strength. For meniscal-type implants, the reinforcing matrix can extend out from the peripheral rim of the hydrogel, to allow secure anchoring to soft tissue such as a joint capsule. For bone-anchored implants, a porous anchoring layer enables tissue ingrowth, and a non-planer perforated layer can provide a supportive interface between the hard anchoring material and the softer hydrogel material.

Abstract: A device for surgical implantation to replace damaged tissue in a joint (such as a meniscus in a knee) is created from a hydrogel that is reinforced by a three-dimensional flexible fibrous mesh. In a meniscal implant, the mesh is exposed at one or more locations around the periphery, to provide anchoring attachments that can be sutured, pinned, or otherwise securely affixed to tissue that surrounds the implant. The fibrous mesh should extend throughout most of the thickness of the hydrogel, to create an “interpenetrating network” (IPN) of fibers modelled after certain types of natural body tissues. Articulating surfaces which will rub and slide against cartilage should be coated with a hydrogel layer that is completely smooth and nonabrasive, and made of a material that remains constantly wet. This composite structure provides a meniscal implant with improved strength, performance, and wettability compared to implants of the prior art.

Abstract: A load-sharing resorbable scaffold is used to help transplanted chondrocytes or other cells generate new cartilage in a damaged joint such as a knee, hip, or shoulder. These scaffolds use two distinct matrix materials. One is a relatively stiff matrix material, designed to withstand and resist a compressive articulating load placed on the joint during the convalescent period, shortly after surgery. Due to the requirement for relatively high stiffness, this material must be denser and have less pore space than other matrices, so it will not be able to support highly rapid cell proliferation and cartilage secretion. The second material comprises a more open and porous matrix, designed to promote maximal rapid generation of new cartilage. In one preferred geometric arrangement, the stiffer matrix material is used to provide an outer rim and one or more internal runners, all of which can distribute a compressive load between them.

Abstract: This invention relates to a surgical implant which contains a relatively soft component, such as a hydrogel or gel-like component, that is affixed to a harder and stiffer material. One such implant is designed to replace a segment of damaged cartilage in a knee, hip, shoulder, or other joint. Instead of attempting to bond a gel-like material to a hard surface with a relatively flat interface, this improved device provides a “multi-perforated non-planar” (MP/NP) interface between the two types of material. This type of MP/NP interface can provide a stronger and more durable gel structure, and it can enable the water molecules in the gel component to disseminate and distribute compressive and shear loads in a more even manner, reducing the risk of tearing or other damage.

Abstract: A non-resorbable implant for repairing or replacing damaged or diseased cartilage in a mammalian joint (such as a knee) is disclosed. This implant uses a relatively soft and bendable “bearing surface”, which is bonded or otherwise coupled (preferably through one or more intermediate layers that provide greater strength) to a flexible anchoring grid. All components which make up the implant should be flexible, so that the implant can be rolled up and surgically inserted into a joint using a minimally invasive incision, preferably by arthroscopic means. In one embodiment, an anchoring grid is implanted first and secured to a prepared bone surface, using pins, cement, or other suitable means. The component with the bearing surface is then “unrolled” by the surgeon across a relatively small area of bone condyle that has been denuded of its cartilage cover.

Abstract: A device designed for surgical implantation to replace damaged tissue (such as a meniscus in a knee) is disclosed, having a hydrogel component reinforced by a three-dimensional mesh. The mesh component provides strength and structural support for the implant, which has at least one articulating surface, and at least one anchoring surface. In one embodiment, the mesh emerges from one or more selected locations around the peripheral rim of a meniscal implant, to provide anchoring attachments that can be sutured, pinned, clipped, or otherwise securely affixed to the fibrous capsule that surrounds the knee. Preferably, the rim surface should be porous, to promote scar tissue (or, in some cases, bone tissue) ingrowth into the implant, to create a strong permanent anchoring support for the implant.

Abstract: A flexible "scaffold" envelope is disclosed which can be used to replace damaged cartilage in knees, shoulders, or other joints of a mammalian body. Designed for use in arthroscopic surgery, the envelope is sufficiently flexible to allow it to be rolled up or folded and inserted into a knee or other joint via a small skin incision. Before insertion, a segment of damaged cartilage is removed from a bone surface, and the bone surface is prepared, using various tools and alignment guides disclosed herein. After the envelope is inserted into the joint, it is unfolded, positioned properly, and anchored and cemented to a bone surface. After anchoring, the envelope is filled via an inlet tube with a polymeric substance that will set and solidify at body temperature. During filling and setting, the surgeon can manipulate the exterior shape of the scaffold envelope, to ensure that the implant will have a proper final shape after the polymer has cured into fully solidified form.