Zimmer Gmbh

Bristol-myers Squibb Compnay

Bristol Meyers Squibb Company

Insall, John

William Rohr

Mark Alan Heldreth

John N Insall

Audrey M Beckman

Roy Yoshikazu Hori

Vince Webster

Steve Zawadski

Kyoko Ohkuni

Melissa A Broderick

Tony Gonzalez

Johnc/oMary V Insall Insall

Audrey Beckman

A femoral knee implant includes a fourth compartment of articulation. The superior posterior articulating surface is achieved by first increasing the thickness of the superior posterior condylar portion of the femoral component to widen the superior posterior edge of the posterior condyle. Second, the newly created surface at the superior posterior condyle is smoothly rounded to provide an articular surface with no sharp changes in the surface contours. In one embodiment, the fourth articular compartment of this invention is provided in a one piece femoral design. In another embodiment, it is provided as a modular addition to an existing prior art femoral component. In another embodiment, the fourth compartment is combined with a posterior stabilized (PS) TKR design that includes a tibial post and cooperating femoral cam characterized by low engagement of the cam on the spine.

Four compartment knee

A method of manufacturing an articulating bearing surface for use in an orthopaedic implant uses a supply of ultra-high molecular weight polyethylene particles which are irradiated with sufficient radiation energy to crosslink at least a portion of the ultra-high molecular weight polyethylene. The irradiated particles are then formed into an orthopaedic bearing surface.

Method of manufacturing an articulating bearing surface for an

An instrument 2 used to install both the outer shell 40 and bearing liner 50 of a conventional acetabular cup assembly 4. Instrument 2 includes an impactor 30 and a reversible cup or head component 10, which is adapted for driving shell 40 into the acetabulum and for seating bearing liner 50 into the shell. Head component 10 has a rounded semi-spherical surface 12 on one end and a substantially flat surface 14 on the opposite end. Impactor 30 includes a longitudinal extension 36 which can be inserted into a bore 20 in head component 10 from either direction to secure the head component to the impactor. When instrument 2 is used to seat shell 40 into the acetabulum, head component 10 is fitted to impactor 30 with semi-spherical surface 12 facing outward for abutment against inner surface 44 of shell 40. Shell 40 is connected to the distal end 39 of extension 36, which protrudes from semi-spherical surface 12 of head component 10. When instrument 2 is used to seat bearing liner 50 into shell 40, head component 10 is connected to impactor 30 with flat surface 14 facing outward for abutment against bearing liner 50.

Instrument for installing an acetabular cup assembly

The metal lock ring of the invention has an oblong exterior periphery which allows the ring to have a small 'width' and a larger 'height.' The small 'width' provides a strong locking mechanism on the poly liner and the larger 'height' allows the ring to remain secure within the groove of the metal shell prior to and during assembly of the polyethylene liner. The ring has a chamfer on its inside leading edges defining its width to facilitate assembly of the liner. This optimizes the ease of assembly and is simpler and more economically to produce than a chamfer all the way around the oblong ring. In the preferred embodiment, the lock ring has a constant thickness such that the inner periphery and the outer periphery are oval. In an alternative embodiment, the metal lock ring has a round inner diameter and a round outer diameter that are not concentric, thereby creating a thickening of the ring at one end. The shape of the alternative lock ring provides for substantial contact between the lock ring and the poly liner about the liner. The thickened area of the ring retains the ring within the metal cup prior to and during assembly of the poly liner. The thickened portion of the ring may have scallops or notches formed therein to increase the flexibility of the ring.

Locking ring for an acetabular cup

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Cincinnati, OH, United States of America

William Rohr