A Clinical Investigation of the M2a- Taper™ Hip System

Inclusion Criteria: * Patients having primary cemented or cementless total hip replacement for non-inflammatory degenerative joint disease (NIDJD), or any of its composite diagnoses of: 1. Osteoarthritis, 2. Avascular Necrosis, 3. Traumatic arthritis, 4. Subcapital fracture, 5. Legg Perthes, 6. Slipped Capital Epiphysis, 7. Fracture of the pelvis, 8. Diastrophic Variant * Patients with full skeletal maturity. * Patients undergoing unilateral total hip arthroplasty or bilateral total hip arthroplasty, either staged or simultaneously. * Patients of all races and gender. * Patients who are able to follow postoperative care instructions. * Patients who are able and willing to return for follow-up evaluations. * Patients have a preoperative total Harris Hip Score less than 70 with at least moderate pain. Exclusion Criteria * Patients diagnosed with inflammatory degenerative arthritis (IDJD) to include the following composite diagnoses: rheumatoid arthritis, systemic lupus erythematous, pigmented villonodular synovitis, juvenile rheumatoid arthritis and other arthritic processes of inflammatory or autoimmune etiology. * Patients less than 18 years. * Patients with the presence of a previous prosthetic hip replacement device (any type, including surface replacement arthroplasty, endoprosthesis, etc.) in the hip joint to be operated. * Patients with previous Girdlestone procedures. * Patients with above the knee amputation of the contralateral and/or ipsilateral leg. * Patients with osteoporosis, or marked bone loss which would preclude proper fixation of the prosthesis. * Patients who are pregnant. * Patients with an active or suspected infection in or around the hip. * Patients with Parkinson's disease. * Patients with vascular insufficiency, muscular atrophy, or neuromuscular disease in the affected limb. * Patients with severe instability or deformity of the ligaments and/or surrounding soft tissue which would prelude stability of the prosthesis. * Patients with a highly communicable disease or diseases that may limit follow-up (e.g. immuno-compromised conditions, hepatitis, active tuberculosis, neoplastic disease, etc.). * Patients unwilling or unable to comply with a rehabilitation program for a cemented or cementless total hip replacement or who indicate difficulty or inability to return for follow-up visits prescribed by the study protocol. * Patients with previous hip surgery or conditions that may interfere with the total hip replacement's survival or outcome, e.g., Paget's disease, Charcot's disease, severe osteoporosis compromising bone stock (Dorr type C bone). * Patients who qualify for inclusion in the study, but refuse consent to participate in the study. * Patients with a "fused" hip. * Patients who have had a total hip arthroplasty on the contralateral hip within the last year.