Abstract: An endplate for an intervertebral prosthesis prosthesis endplate of the invention includes: a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp for preparing a surgical site for implantation of the prosthesis has a rasp head having a pivot point and rasp teeth arranged to produce a recess or seat of predetermined shape.

Abstract: A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk is an expandable container having flexible walls, the container being adapted to be inserted into a central cavity of an intervertebral disk through a narrow cannula, and the flexible walls are made from a biocompatible hydrogel. A preferred hydrogel is a cryogel formed from an aqueous solution of poly(vinyl alcohol) and poly(vinyl pyrrolidone). The prosthesis may be prepared by dip-coating a mandrel with an aqueous solution of a hydrogel-forming polymer or mixture of such polymers, gelling the coated solution by chilling, and subjecting the gelled coating to a series of repeated freeze-thaw treatments. In use, the prosthesis is inserted into a central cavity of an intervertebral disk and filled with biocompatible material, e.g., a biocompatible liquid, a biocompatible polymer, and a biocompatible hydrogel, particularly a thermogelling hydrogel.

Abstract: In an intervertebral disc prostheses having a pair of rigid endplates and an elastomeric core structure between the endplates. The core structure is designed to provide desired functional characteristics of the prosthesis.

Abstract: A modular prosthetic device is provided for replacement of the knee. The device is assembled from a plurality of components, each of which can be inserted through a small incision. After inserting the components through the incision, the device can be assembled within the knee cavity. The modularity of the device enables a surgeon to replace only those regions of the knee that are diseased or damaged, thereby avoiding a complete knee replacement. If, at a later time, additional regions of the knee become diseased or damaged, those additional regions of the knee can be replaced by additional device components and those additional components can be connected to the previously implanted components. By replacing only those regions of the knee that are diseased or damaged and by implanting each of the components through the small incision, the surgery is minimally invasive and, therefore, requires reduced time for healing and rehabilitation.

Abstract: A femoral component (100) for a total knee joint replacement has a modular structure including a number of segments (102, 112), each of the segments (102, 112) having a femoral fixation surface (104, 114) for attachment to the distal end of a femur and at least one assembly surface (108) for joining with an adjacent segment (102, 112) of the modular femoral component (100). The assembly surfaces (108) are generally planar and arranged to be oriented generally in a plane extending in a proximal-distal direction and in an anterior-posterior direction when the femoral fixation surface (104, 114) is positioned on the distal end of the femur. Although the assembly surfaces (108) are generally planar, they may be shaped or provided with complementary structures (120) to assure self-alignment when the segments (102, 112) are assembled.

Abstract: A nucleus pulposus of an intervertebral disc is supplemented or replaced by an elongated, physiologically fully hydrated hydrogel prosthesis inserted into the central region of an intervertebral disc, where it can fold upon itself to form a prosthesis body within the central region of the annulus fibrosus. The hydrogel prosthesis may have expanded portions that assist in preventing expulsion of the prosthesis through the insertion aperture. An instrument for inserting the prosthesis has a cutter for severing the elongated prosthesis within the central region of the intervertebral disc after a sufficient amount has been implanted.