28 mm Ceramic-on-Ceramic Acetabular Cup Total Hip Replacement Study

Total Hip Arthroplasty (THA) is the surgical reconstruction of the hip joint through replacement of the femoral head and the acetabular articulating surfaces with fixed prosthetic devices. The goals of THA are relief from pain, restoration of function, and correction of deformity. THA is one of the most common adult reconstructive procedures. Over the past 25 years, patients who have needed to have their hip joint replaced, either due to trauma or arthritic disease, typically have had their hip joint bone articular surfaces replaced with a metal hip stem, metal ball head (either stainless steel or chrome cobalt) and a plastic acetabular cup (metal/metal/plastic). While the basic device has remained essentially unchanged over that period, technological advancements in implant designs and materials, and improvements in surgical technique and instrumentation have made THA one of the most durable and successful procedures in medicine. Reproducible, high-quality, short-term and mid-term results are attained regularly, and total hip replacements commonly last 10 to 15 years and longer. The success of this procedure has allowed its expansion into a wider, and often younger and more active population. In spite of the improvements in THA, little change has occurred for the acetabular cup liner, which is usually made out of Ultra High Molecular Weight Polyethylene plastic (UHMWPe). Because it is plastic and inherently soft and somewhat pliable under load, the cup's articular surface must inevitability wear and produce debris. This biologic response is now thought to be a significant contributor to prosthetic component loosening, a primary failure mode of THR. UHMWPe also degrades with time in the body. As concerns about polyethylene wear and the associated untoward effects of the generated wear debris, and as THA continues to be used in younger and higher-demand patients with increasing life expectancies, interest in ceramic on ceramic total hip prosthesis has been renewed. An alumina ceramic-on-ceramic acetabular coupling has been employed as an alternative to metal/polyethylene couplings. This ceramic-on-ceramic coupling has many advantages, including the elimination of polyethylene from the device system, wear rates that are appreciably less than those experienced with metal/polyethylene couplings and reduced biologic reactivity. The potential benefits of an alumina ceramic/ceramic bearing are significant.