The study is designed to evaluate artificial hips with a 28 mm ceramic head and a ceramic liner to determine whether they perform as well as artificial hips with a 28 mm ceramic head and a polyethylene liner.

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.

Inclusion Criteria:

• Non-inflammatory degenerative joint disease. Composite diagnoses of NIDJD include osteoarthritis, avascular necrosis, post-traumatic arthritis, slipped capital femoral epiphysis (SCFE), fracture of the pelvis, and developmental dysplasia.
• X-ray evaluation confirms the presence of NIDJD
• Femoral and acetabular bone stock is sufficient, regarding strength and shape, and is suitable to receive the implants.
• Individuals 20 to 75 years of age at the time of surgery
• Patients with a previous total hip replacement of the contralateral leg who have a pain rating of none or slight and who are at least one year post arthroplasty are eligible for participation in the study.
• Harris Hip Score of 70 or lower
• Pain at least Moderate

Exclusion Criteria:

• Presence of a previous prosthetic hip replacement device (any type, including surface replacement arthroplasty, endoprosthesis, etc.) in the hip joint to be operated.
• Previous Girdlestone procedure (resection arthroplasty) or surgical fusion of the hip to be operated.
• Acute femoral neck fracture.
• Above knee amputation of the contralateral and/or ipsilateral leg.
• Patients with bilateral degenerative joint disease requiring staged or simultaneous hip replacements.
• Patients with an existing total hip arthroplasty in the contralateral hip with a Harris Hip pain rating of mild, moderate, marked or totally disabled.
• Patients who have undergone total hip arthroplasties in their contralateral hips within the past 12 months.
• Patients with a known allergy to metal (e.g. jewelry).
• Skeletally immature patients (tibial and femoral epiphyses are not closed). Evidence of active infections that may spread to other areas of the body (e.g., osteomyelitis, pyogenic infection of the hip joint, overt infection, urinary tract infection, etc.).
• The presence of highly communicable disease or diseases that may limit follow-up (e.g., immuno-compromised conditions, hepatitis, active tuberculosis, etc.).
• Presence of known metastatic or neoplastic disease.
• Significant neurologic or musculoskeletal disorders or disease that may adversely affect gait or weight bearing, (e.g., muscular dystrophy, multiple sclerosis).
• Conditions that may interfere with the total hip arthroplasty's survival or outcome, (e.g., Paget's disease, Charcot's disease).
• Any patient believed to be unwilling or unable to comply with a rehabilitation program for a cementless total hip replacement or who indicates difficulty or inability to return for follow-up visits prescribed by the study protocol.
• Patient is known to be pregnant, a prisoner, mentally incompetent, and/or alcohol or drug abuser.
• Any systemic steroid therapy, excluding inhalers, within three months prior to surgery.
• Patients carrying the diagnosis of inflammatory degenerative arthritis (IDJD) to include the following composite diagnoses: rheumatoid arthritis, systemic lupus erythematosus, pigmented villonodular synovitis, juvenile rheumatory arthritis and other arthritic processes of inflammatory or autoimmune etiology.
• Patients requiring structural bone grafts in order to support the prosthetic component(s) or to shape the bone to receive the implant(s).
• Patients who refuse to provide consent to participate in the clinical investigation.