A Trial Comparing Mini-posterior Approach and Direct Anterior Approach

• The postoperative rate of improvement in functional outcome as measured by the Harris Hip Score (HHS), WOMAC (Western Ontario), and SF-12 over time. [ Time Frame: 3 wk, 6 wk and 12 mo ] [ Designated as safety issue: No ]
• The difference between groups with respect to implant position and leg length. [ Time Frame: 3 wk, 6 wk, 12 mo ] [ Designated as safety issue: No ]

The purpose is to determine if differences exist in the attainment of functional milestones that reflect activities of daily living between mini-posterior and direct anterior approach total hip arthroplasty (THA). The investigators also hope to determine if the general health outcome after direct anterior total hip arthroplasty was better than that after mini-posterior-incision total hip arthroplasty as measured with Short Form-12 (SF-12) scores, and to evaluate variation of surgical factors of the two procedures on the basis of the operative time, component positioning, and occurrence of early complications.

• Procedure: Mini-Posterior surgical approach for total hip arthroplasty
  Mini-Posterior surgical approach for total hip arthroplasty
• Procedure: Direct Anterior surgical approach for total hip arthroplasty
  Direct Anterior surgical approach for total hip arthroplasty

• Active Comparator: Mini-Posterior Approach
  Intervention: Procedure: Mini-Posterior surgical approach for total hip arthroplasty
• Experimental: Direct Anterior Approach
  Intervention: Procedure: Direct Anterior surgical approach for total hip arthroplasty

Inclusion Criteria:

• The subject is willing and able to understand, sign and date the study specific Patient Informed Consent and HIPAA authorization to volunteer participation in the study.
• The subject is between 25 and 80 years of age at the time of surgery.
• The subject has elected to undergo primary total hip arthroplasty for osteoarthritis.
• The subject is psychosocially, mentally and physically able to comply with the requirements of the study including post-operative clinical, radiographic evaluations and completion of patient questionnaires.
• The subject is skeletally mature.

Exclusion Criteria:

• The subject has a BMI greater than 35.
• The subject has had a previous total hip arthroplasty.
• The subject has inflammatory arthritis.
• The subject has any type of infection.
• The subject has developmental dysplasia of the hip.
• The subject has a known metal allergy.
• The subject has an extreme offset of greater than 50 mm.
• The subject has an acetabular deformity requiring advanced reconstructive techniques.
• The subject has Charcot's disease.
• The subject has Paget's disease
• Dependence on narcotics for 6 months (or longer)