Abstract:
Prosthetic joint replacement ensemble includes an artificial joint implant component having a non-bone-interfacing rough surface for ingrowth of fibrous tissue, preferably about a peripheral boundary. The component can be made of metal, and have the rough surface provided by porous metal coating. When the prosthesis is implanted, the extramedullary rough surface engenders ingrowth of soft fibrous tissue so that it forms, as it were, a reconstituted capsular “bag” in which wear debris from the joint, for example, ultra high molecular weight polyethylene wear debris, is trapped, thus keeping those particles from gaining access to supporting bone at the bone-prosthetic interface. And so, with mitigation of wear debris dispersion, debris wear-induced osteolysis can be ameliorated.
Abstract:
An acetabular prosthesis including a ceramic shell having multiple layers and a polymer liner formed integrally with the shell. The acetabular prosthesis shell is formed of a ceramic wherein several layers with varying porosities and thicknesses are sintered together to form a unitary structure. A polymer inner liner forms a bearing within the shell to receive the ball of a femur or femur prosthesis. The polymer liner is formed in the ceramic shell and includes a plurality of portions which interdigitate into the pores of the inner porous layer of the ceramic shell.
Abstract:
A joint prosthesis comprising at least a first and a second load carrying member, the first load carrying member being substantially more shock absorbing and resilient than the second load carrying member.
Abstract:
A process for forming an oriented orthopaedic implant prosthesis bearing, net-shape bearing, or near net-shape bearing includes the step of placing an irradiated UHMWPE preform or puck of a volume sufficient to accommodate the bearing in a compression mold and compression molding the irradiated preform. The molding is accomplished by applying heat and pressure to form the preform into a desired shape. The compression molding induces biaxial orientation in the formed bearing.
Abstract:
An implantation method is described which involves the successive introduction of projecting multilateral needles into the spongy bone of a joint. The needles are symmetrically spaced on the terminal surfaces of the endoprosthesis up to a resistance edge on one portion of an endoprosthesis and up to a resistance surface on a second portion of the endoprosthesis. The remaining free area between the projecting multilateral needles is filled up to the terminal surfaces in the "biological silence" by osteoblasts. The endoprosthesis also includes a glenoid cavity and a head which have round terminal surfaces with the projecting multilateral needles placed thereon. The projecting multilateral needles have different lengths and mutually parallel axes which are perpendicular to the planes in which the round resistance edge of the glenoid cavity and the resistance plane of the head are located.
Abstract:
An artificial hip-joint having a construction capable of reducing abrasion of a polyethylene layer formed within the acetabulum cup when the head of the femur pivots in the acetabulum cup. The artificial acetabulum cup is implanted in the acetabulum of a user's pelvic bone and includes a hollow hemispherical member made of a metal. The polyethylene layer is formed on the inner surface of the hemispherical member. A femur head holder is fixed to the femur. The femur head holder includes a spherical metal femur head pivotally held in the artificial acetabulum cup, a shaft coupled at an upper end thereof to the femur head and adapted to support the femur head, a housing extending inclinedly through the greater trochanter of the femur and adapted to receive the shaft therein in such a manner that it rotates with respect to the shaft, and bearings mounted between the shaft and the housing and adapted to support axial and radial load applied to the shaft at the femur head by the weight of the user. The bearings allows the housing to rotate with respect to the shaft when the user performs a movement involving a rotation of the femur head in the acetabulum cup, so that the movement of the user can be conducted while preventing the rotation of the femur head in the acetabulum cup.
Abstract:
A kit for implanting a socket joint implant has an outer cup (1), an inner cup (2) and fasteners (3, 3a) which are fitted to radially project from the outer cup (1). Each fastener includes a bearer plate (17) arranged on a shaft-like supporting part (18) which is able to bear in an anchoring bore (6) in the bone tissue (5), and a head part (20) which is connected detachably to the supporting part (18) and can be screwed tight from the inside of the outer cup (1) into a guide bore (11) of the cup. The supporting part (18) has a diameter (A) which is less than the diameter (d1) of the guide bore (11). The kit is pre-assembled outside the region of implantation and positioned in the region of implantation while the fasteners (3, 3a) are pulled in towards the center of the outer cup (1). The fasteners (3, 3a) are then pushed into the anchoring bores ( 6) and screwed tight to the outer cup (1) with head parts (20). The kit is adaptable to different anatomical conditions and may be employed as a replacement for a part of the pelvis missing in the region of the hip socket.
Abstract:
A prosthesis for insertion into a long bone includes a stem which has been shaped so as to evenly distribute low stress to the bone. A synthetic resinous sheath surrounds the stem which effects a contact surface between the stem and the bone. The prosthesis includes an extension which extends outwardly of the bone and has a ball and socket thereon.
Abstract:
This invention relates to an acetabular cup assembly for total hip replacement and in particular to one including a generally hemispherical socket provided with a tubular neck having internal threads at the lower portion and a plurality of webs around the tubular neck, and a stud adapted to be inserted through the tubular neck of the hemispherical shell member and provided on the upper portion with external threads engageable with the internal threads of the tubular neck, whereby the acetabular cup assembly may be firmly fixed on the bone.
Abstract:
A joint prosthesis comprising two co-operating prosthesis members fastening each to a different joint bone. At least one of the prosthesis members is formed by at least two prosthesis elements one surrounding the other, the one prosthesis element adjacent the bone being provided with fastening means distributed along the outer face and being located inside the outer face when the joint prosthesis is being applied, out of which outer face they can subsequently be moved in order to cause them to penetrate into the bone.The fastening means are formed by pins guided in passages of the prosthesis element. The tipform of these pins could be chosen in relation to the hardness of the bone to be penetrated.Furthermore, the contact faces of the two prosthesis elements could be provided with coating mimicing the elastic and/or resilient features of bone.