The specific aim of this proposed study is to conduct a prospective RSA clinical study at Massachusetts General Hospital involving 50 patients receiving primary total hip replacements. All patients will receive the vitamin E treated polyethylene acetabular inserts. Short-term femoral head penetration and long-term steady state wear of the polyethylene will be measured using both RSA and Martell analysis techniques. Stability of the acetabular and femoral components will be measured in all patients using RSA analysis. The stability of the cemented femoral stems will be compared to the stability of the cementless femoral components as well as to historic data in the literature. In addition, all patients will complete a self-administered questionnaire to assess the clinical outcome of the surgery and patient satisfaction.

Inclusion Criteria:

• Male or female
• 20 to 75 years of age
• Subjects requiring primary total hip replacement
• Subjects with diagnosis of osteoarthritis, avascular necrosis, or traumatic arthritis
• Subjects who demonstrate the ability to return to MGH for follow-up for the next five years.

Exclusion Criteria:

• Subjects with limited life span
• Subjects with difficulty in comprehending study protocol for any reason.
• Subjects with inflammatory disease, previous infection or those requiring revision hip surgery.
• Subjects whose bony structures are so small that a femoral head less than 32mm in diameter must be used.
• Subjects whose bony structure deviates substantially from the general norm sufficiently to require non-standard techniques and non-standard implants. Specific examples of these are total dislocation of the hip, severe coxa vera deformity, severe forms of multiple epiphyseal dysplasia
• Subjects with complex disease entities which significantly increase the risks of the surgery such as any major platelet abnormality, hematological disorder, positive for HIV or any other major medical complication which substantially reduces longevity.
• Female subjects that are pregnant or who may suspect they are pregnant or who plan to become pregnant while participating in this study.