A Trial Comparing Mini-posterior Approach and Direct Anterior Approach

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.

A number of studies have compared surgical approach for total hip arthroplasty. The influence of surgical outcome as a function of approach comparing mini-posterior to direct anterior has not been reported in a randomized, prospective manner.

Standard primary total hip arthroplasty (THA) can reliably alleviate pain, improve function, and improve the quality of life in a broad section of patients with end stage arthrosis of the hip. However, minimally invasive approaches, such as the direct anterior and mini-posterior approaches, have been devised with the goal of decreasing peri-operative pain, speed early postoperative function, and improve patient satisfaction with the procedure, compared with standard THA. These patient centered goals are combined with the surgeon's desire of a safe, reproducible minimally invasive procedure that has durable, properly positioned components.

There are currently no prospective, randomized studies comparing the direct anterior approach to total hip arthroplasty with other minimally invasive approaches. The mini-posterior approach has been studied extensively, with promising results. Others have compared the mini-posterior approach with other minimally invasive procedures, and at the current time, has the most prospective data demonstrating its superiority as a minimally invasive approach. Pagnano performed a prospective, randomized trial comparing the early clinical results of mini -posterior THA with Two-incision THA. The results found that the early attainment of functional milestones was shorter in the mini-posterior group.

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.

Eligibility Criteria:
Inclusion Criteria:

* The subject is willing and able to understand, sign and date the study specific Patient Informed Consent and Health Insurance Portability and Accountability Act (HIPPA) 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)