In this study, the investigators propose to randomize 80 subjects to receive either the Avenir cementless hip stem or a competing, HA-coated hip stem (Corail, DePuy-Synthes) and follow these patients for a period of 2 years post-surgery. The investigators aim to determine if the Avenir cementless hip stem has equivalent or better fixation and clinical outcomes compared to a predicate hip stem with longer clinical history.

This is a multi-center, randomized controlled trial of patients undergoing primary total hip arthroplasty. This study will be focused on enrollment at a single site with possible expansion to additional centers should patient enrollment occur at a slower than expected rate. Decision to expand the study to additional centers will be mutually agreed upon by both the clinical site and the study sponsor.

Patients will be randomized to two study groups:

1. Zimmer Avenir cementless, HA-coated femoral hip stem with matching Trilogy IT cup;
2. DePuy-Synthes Corail cementless, HA-coated, non-collared femoral hip stem with matching Pinnacle cup Patient allocation to the study groups will occur following a randomized 4-block design.

Inclusion Criteria

• Symptomatic osteoarthritis of the hip undergoing primary total hip arthroplasty
• Between the ages of 18 and 79 inclusive
• Patients willing and able to comply with follow-up requirements and self-evaluations
• Ability to give informed consent

Exclusion Criteria

• Requires specialty implant (e.g., suspected metal allergy, coxa vera implant)
• Avascular necrosis
• Unresolved infection of the hip
• Hip fracture
• Hip dysplasia
• At risk for loss to follow-up
• Prior surgery to the ipsilateral hip
• Severe proximal femoral deformity preventing the use of standard proximal press-fit femoral components
• Medical condition precluding major surgery
• Current or pending patient incarceration