Zimmer, Inc

The editorial assistance of Mrs. Shirley Maimone in the preparation of this manuscript is gratefully acknowledged. The author also gratefully acknowledges the contributions of his students Satish Pulapura, Chun Li, Farzana Haque, and the contributions of his coworkers Israel Engelberg and Fred Silver. This work was supported by NIH grant GM 39455, by Zimmer Inc., and by NSF grant DMR-8902468. 

Additional source of information for UHMWPE acetabular cups arises from the quantitative analysis of polarized Raman spectra. Figure 17.6 shows photographs and the outcome of such analysis for two acetabular cups, which were retrieved after substantially different in vivo lifetimes. The retrieved acetabular cups were both belonging to male patients and sterilized by y-rays, but produced by different processes. One acetabular component (manufactured in 2002 by Biomet Inc.) was prepared by isostatic compression molding and sterilized before implantation by a dose of 33 kGy of y-rays. It was retrieved due to infection after 2 years 5 months. This cup will be referred to as the short-term retrieval. The other retrieval (manufactured in 1995 by Zimmer Inc.) was prepared by Ram-extruded molding and sterilized in air by a dose of 25-37 kGy of y-rays. For this latter cup, the follow-up pe-... 

Contemporary nitrogen-filled barrier packaging for gamma sterilization of UHMWPE components used by Zimmer, inc. (Warsaw, iN). 

Special thanks to Janet Krevolin (Centerpulse Orthopaedics, Inc.), Ray Gsell (Zimmer, Inc.), Shi-Shen Yao and Paul Serekian (Howmedica Osteonics Corp.), Jorge Ochoa and Mark Haynes (DePuy Orthopaedics, Inc.), and David Schroeder (Biomet, Inc.) for their helpful discussions and editorial assistance with this chapter. 

Longevity component for hip arthroplasty with packaging (Zimmer, Inc., Warsaw IN). (A) 22-mm diameter Longevity acetabular liner. (B) Packaging of Longevity. 

Prolong is based on WIAM technology patented by Massachusetts General Hospital and licensed to Zimmer, Inc. (Warsaw, IN). Prolong was clinically introduced for cruciate-sparing, NexGen knee component systems in 2002. 

Gsell R, King R, Swarts D. Quality indicators of high-performance UHMWPE. Report No. Warsaw Zimmer, Inc. 1997. 

FIGURE 3.8 Contemporary gas-permeable packaging for ethylene sterilization of Durasul highly crosslinked UHMWPE components, used by Zimmer, Inc. (Warsaw, Indiana, USA). 

Today, ethylene oxide continues to be used as a contemporary sterilization method for UHMWPE by major orthopedic manufacturers. Smith Nephew, Inc. (Memphis, Tennessee, USA) and Wright Medical Technology, Inc. (Arlington, Tennessee, USA) have employed ethylene oxide since the 1990s [4]. More recently, however, Zimmer, Inc. (Warsaw, Indiana, USA) chose ethylene oxide for sterilization of their highly crosslinked UHMWPE (Durasul) hip and knee products [29] (Figure 3.8). 

Gas plasma has gained increased acceptance as a method for sterilizing UHMWPE components for total joint replacement. Gas plasma (Plazlyte system) has been used by DePuy Orthopaedics, Inc., (Warsaw, Indiana, USA) since the 1990s to routinely sterilize UHMWPE components [4] (Figure 3.9). Zimmer, Inc., (Warsaw, Indiana, USA) and Stryker (Mahwah, New Jersey, USA) currently employ gas plasma for sterilization of highly crosslinked UHMWPE components (e.g., Longevity, Prolong, X3). 

Commercial release of Poly II—Carbon Fiber Reinforced UHMWPE for THA/TKA by Zimmer, Inc. 

Highly crosslinked UHMWPE is now the most widely used alternative to conventional UHMWPE. Today, four out of the five major orthopedic manufacturers offer highly crosslinked UHMWPE for total knee arthroplasty (Prolong, Zimmer, Inc. X3, Stryker Orthopaedics XLK, DePuy Orthopedics and EPoly, Biomet, Inc.). However, there is not universal agreement in the clinical community that highly crosslinked... 

This chapter was not written with the financial support of any manufacturer of total elbow arthroplasty systems. However, the manufacturers of some of the products mentioned in this review were contacted by the author and given the opportunity to verify the factual accuracy of the information relating to their products. Institutional support for Judd Day has been received from Zimmer, Inc. I would like to thank Chris Espinosa for many of the illustrations in this chapter, Madeline Olsen for editorial assistance, and Drs. Matthew Ramsey and Bernard Morrey for their insight into elbow arthroplasty. 

We would like to thank Dr. William H. Harris for his help with the biocompatibility literature survey and for his insights. The work discussed by the authors has been supported by National Institute for Musculoskeletal and Skin Diseases Grant No. AR051142, research grants from Biomet, Inc., Zimmer, Inc., the William H. Harris foundation, and departmental funds. 

The authors would like to thank Werner Schneider, Zimmer, Inc., for his feedback regarding the history of VITASUL. 

In the 1970s, carbon fiber-reinforced (CFR) UHMWPE composites were considered for orthopedic implants and were even commercially introduced (Poly 11, Zimmer, Inc., Warsaw, Indiana, USA). However, catastrophic short-term clinical failures [2, 3] eventually led to the abandonment of Poly 11 and the perception for decades, among surgeons and researchers alike, that UHMWPE composite materials may not be appropriate for orthopedic bearing applications. Today, with the interest in UHMWPE development that was stimulated by radiation and thermal processing techniques, as well as the growing use of UHMWPE composites in nonmedical arenas, there is renewed curiosity about these materials for biomedical applications. 

One carbon-UHMWPE composite, commonly known as Poly II (Zimmer, Inc., Warsaw, Indiana, USA), was developed commercially and used clinically. The CFR-UHMWPE was reinforced by chopped, randomly oriented carbon fibers in a direct compression molded UHMWPE matrix [4]. The carbon fiber reinforcement was initially considered to be responsible for improved wear behavior relative to UHMWPE during initial experimental testing conducted by the manufacturer [5]. However, further studies ultimately revealed that such performance came at the expense of the ductility, decreased crack resistance, and the fiber-matrix interface of the composite [6]. Subsequent wear studies also showed evidence of fiber disruption at the surface and abrasive wear of the metallic counterface [7]. Furthermore, occasional difficulties in the manufacture of the composite material resulted in incomplete consolidation of the powder and carbon fibers in certain implants [8]. Thus, after its clinical introduction, Poly II was found to exhibit wear, fracture, and extensive delamination [2, 3,9], and, as a result, the material was eventually withdrawn [ 10]. 

Fading G, inventor Zimmer Inc., assignee. Human body implant of graphitic carbon fiber reinforced ultra-high molecular weight polyethylene. United States Patent No. 4,055,862-, 1977. 

Price HC, Lin ST, Hawkins ME, Parr JE, inventors Zimmer, Inc., assignee. Reinforced polyethylene for articular surfaces. United States Patent No. 5,609,638 1997. 

This chapter was made possible by the assistance of colleagues at the five orthopedic manufacturers of highly crosslinked UHMWPE, who provided access to representative products and processing information Jordan Freedman and David Schroeder (Biomet, Inc.) Keith Greer (DePuy Orthopedics) Hallie Brinkerhuff (Zimmer, Inc.) Alissa Sellers (Stryker Orthopedics) and Mark Morrison (Smith Nephew). 

The work discussed by the authors has been supported by research grants from Bioster (Bergamo Italy), Lima Lto., and Zimmer, Inc. 

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