A Clinical Trial of a Metal on Poly Component Versus CORAIL Stem: A Bone Mineral Density Study

The main goal is to prospectively evaluate bone mineral density adjacent to the femoral component and femoral bone remodeling of two different designs: CORAIL impaction broach titanium stem compared to a modular titanium femoral stem (Tri-lock). The investigators expect the CORAIL femoral stem group to show significantly less bone loss on the femoral side as compared to the Tri-lock group. The primary outcome is percent change in bone mineral density (BMD) (g/cm2) from baseline (10-14 days post-op) to the two year post-operative interval, as measured radiographically in zones 1 and 7.

Patients will be randomized to one of the two treatment groups prior to surgery. Each patient will be evaluated at their regularly scheduled 10-14 days, 3, 6, 12 and 24 month visits following surgery.

Bilateral DXA bone mineral density tests will be performed at 10-14 days following surgery (baseline assessment) and at 6, 12, and 24 months post-operatively.

Urine and serum samples (measures of bone turnover) will be collected at 3, 6 and 12 months post-operatively after an overnight fast.

The Harris Hip Score will be completed at each post-operative visit except the immediate (10-14 days), when risk of dislocation precludes a determination of range of motion. At the 3, 6, 12 and 24 month post-operative visits, the patient will complete the SF-36 Item Health Survey, WOMAC and UCLA activity scale.

Inclusion criteria

• Patients who are undergoing primary hip surgery for osteo/degenerative arthritis (does not include traumatic arthritis, congenital hip dysplasia, or avascular necrosis).
• Patients who are skeletally mature, as determined by Risser sign or at least 18 years of age
• Patients under 75 years of age
• 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.

Exclusion criteria

• Patients with previous fusions, acute femoral neck fractures and above knee amputations.
• Patients with evidence of active local infection
• Patients with neurologic or musculoskeletal disease that may adversely affect gait or weight-bearing.
• Patients who have previously undergone an ipsilateral hemi resurfacing, total resurfacing, total bipolar, unipolar or total hip replacement device, or any prior hip surgery or retained internal fixation.
• Patients who are anticipated to require contralateral hip surgery in the next year
• Patients with known disorders of bone metabolism, systemic inflammatory disorders, and use of drug medications, including oral steroids, HRT, Tamoxifen, calcium, or vitamin D in the past year, and any past bisphosphonate therapy.
• Patients with a Body Mass Index (BMI) > 35
• Patients with neuropathic joints
• Patients with severe documented psychiatric disease
• Patients requiring structural bone grafts
• Patients with an ipsilateral girdlestone
• Patients with sickle cell disease
• Patients with major acetabular bone stock deficiency