This study compares the change (loss) of bone mineral density (BMD) that occurs in the proximal femur after hip resurfacing and total hip replacement.

This study compares the change (loss) of bone mineral density (BMD) that occurs in the proximal femur after hip resurfacing and total hip replacement. The goal is to evaluate the bone loss in the proximal femur resulting from hip resurfacing surgery and to compare this to the bone loss in the proximal femur resulting from total hip arthroplasty.

Inclusion Criteria:

• Age of at least 20 years
• Osteoarthritis
• Elective Total Hip Arthroplasty / Resurfacing
• Signed Informed Consent

Exclusion Criteria:

• Osteoporosis
• Revisions
• Femoral dysplasia
• Trochanteric osteotomy
• Inflammatory arthritis
• Breast-feeding, pregnancy, or women of child-bearing potential without documentation of a negative pregnancy test and not utilizing contraception
• Patients with a history of having taken or currently taking PTH, fluoride therapy or strontium ranelate or patients taking other chronic medications that in the Investigator's opinion are known to affect bone mineral density in a substantial way
• Patients with severe medical condition(s) that in the view of the Investigator prohibits participation in the study
• Use of any other investigational agent in the last 30 days

Adult patients undergoing hip replacement or resurfacing for osteoarthritis