A Comparison of a Resurfacing Hip System to Standard Total Hip Arthroplasty

Inclusion Criteria:

- Patients who are undergoing primary hip surgery for noninflammatory degenerative joint disease (NIDJD). Composite diagnoses for NIDJD include osteo/degenerative arthritis, traumatic arthritis, congenital hip dysplasia, and avascular necrosis.2. Patients who are skeletally mature or at least 18 years of age.3. Patients for whom there is a reasonable expectation that they will be available for each examination scheduled over a two year post-operative follow up period and for annual exams until the last patient entered into the study has achieved two years of follow-up.4. Patients who agree to participate and sign the informed consent form.5. Patients who do not meet any of the exclusion criteria.6. Patients who are already enrolled in the study and present with a need for revision of the metal femoral or acetabular resurfacing components. These patients may have the failed component(s) revised with an investigational component.

Exclusion Criteria:

• . Patients who are less than 18 years of age or are skeletally immature at the time of surgery.2. Patients who present with inflammatory degenerative joint disease or revision surgery other than that specified in the inclusion criteria.3. Patients with previous fusions, acute femoral neck fractures and above knee amputations.4. Patients with evidence of active infection.5. Patients who are pregnant (or plan on becoming pregnant) or who are lactating.6. Patients with neurologic or musculoskeletal disease that may adversely affect gait or weight bearing.7. Patients who have previously undergone an ipsilateral hemi resurfacing, total resurfacing, total bipolar, unipolar, or total hip replacement device.8. Patients with active hepatitis or HIV infection.9. Patients who otherwise meet the study criteria, but refuse to consent in writing to participate in the study. 10. Patients who are obese where obesity is defined as a Body Mass Index (BMI) >35.11. Patients with neuropathic joints.12. Patients with severe documented psychiatric disease.13. Patients requiring structural bone grafts.14. Patients with a documented allergy to cobalt chromium molybdenum.15. Patients with ipsilateral girdlestone.16. Patients with sickle cell disease.17. Patients with significant femoral head or neck deformity or significant acetabular wall deficiency.18. Patients with renal impairment where renal impairment is defined as serum creatinine> 180umol/L.