Metal Ion Release From an FDA-Approved Metal-on-Metal Total Hip Replacement Implant

Inclusion Criteria: * Undergoing cementless primary total hip replacement * Receiving acetabular cup of 52mm or greater * Preoperative level of function and pain same as for conventional hip replacement * Likelihood of obtaining relief of pain and improved function * Full skeletal maturity * Ability to follow instructions * Good general health * Willing to return for follow-up evaluations * X-ray evaluation confirming the presence of NIDJD * Femoral and acetabular bone stock that is sufficient, regarding strength and shape, and suitable to receive the implants Exclusion Criteria: * Age less than 40 years or greater than 80 years at time of surgery * Patients templated to receive an acetabular component smaller than 52mm in diameter * Presence of a previous prosthetic hip replacement device in the hip joint to be operated * Previous girdlestone procedure 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 a diagnosis of inflammatory degenerative arthritis * Skeletally immature * Evidence of active infections that may spread to other areas of the body * The presence of a highly communicable disease that may limit follow-up * Presence of known active metastatic or neoplastic disease * Significant neurologic or musculoskeletal disorders or disease that may adversely affect gait or weightbearing * Any previous hip surgery or conditions that may interfere with the total hip replacement's survival or outcome * Any patient believed to be unwilling or unable to comply with a rehabilitation program for a cementless total hip replacement or indicates difficulty to return for follow-up * Patient is know to be pregnant, a prisoner, mentally incompetent, and/or alcohol or drug abuser * Any patient who qualifies for inclusion in the study but refuses consent to participate in the study * Any steroid therapy, local or systemic, within three months prior to surgery * Patient requiring structural bone grafts in order to support the prosthetic components or to shape the bone to receive the implants * Patient has known allergies to metal, e.g., jewelry * Any patient not meeting all radiographic and clinical parameters for inclusion