The primary purpose of this study is to demonstrate cumulative revision rate of the REDAPT System Monolithic Sleeveless/Sleeved Stem, Fully Porous Acetabular Shell with XLPE liner, and Modular Shell Components (with or without Staple, Slice and Blade Augments) at 10 years.

Retrospective-prospective, single arm, multicenter study of subjects previously implanted with the REDAPT System Monolithic Sleeveless/Sleeved Stem and/or Fully Porous Acetabular Shell with XLPE liner and/or Modular Shell Components (with or without Staple, Slice and Blade Augments).

Inclusion Criteria:

Subjects must meet all of the inclusion criteria to enroll in the study:

1. Subject was considered skeletally mature at the time of surgery and was at least 18 years of age.

2. Subject has undergone hip arthroplasty with the REDAPT Fully Porous Acetabular Shell with XLPE liner or REDAPT Modular Cup Components (with or without Staple, Slice and Blade Augments), and/or Monolithic Sleeveless Stem, and/or Monolithic Sleeved Stem and are at least 3 months post-implantation at this site.

3. Subject required surgery with REDAPT device chosen for one of the following indications:

   1. Advanced degeneration of the hip joint as result of osteoarthritis, avascular necrosis, posttraumatic arthritis, rheumatoid arthritis, or dysplasia (or any of the composites of these conditions).
   2. Fracture-dislocation of the hip, femoral neck fracture or trochanteric fractures of the proximal femur with head involvement that are unmanageable using other techniques.
   3. Revision THA

4. Subject is willing to consent to and to follow the study visit schedule (as defined in the study protocol and ICF), by signing the IRB/IEC approved ICF.

5. Subject is willing and able to participate in required follow-up visits at the investigational site and to complete study procedures.

Exclusion Criteria:

Subjects meeting any of the following exclusion criteria will be excluded from study participation:

1. Subject had an active infection - systemic or at the site of surgery.
2. Subject, in the opinion of the PI, has an emotional or neurological condition that would pre-empt their ability or willingness to participate in the study including mental illness, mental retardation, drug or alcohol abuse.
3. Subject is known to be at risk for loss to follow-up or failure to return for scheduled visits.
4. Subject is incarcerated or is pending incarceration.
5. Subject is enrolled in another clinical study that would affect the endpoints of the study.

Subject has undergone hip arthroplasty with the REDAPT Fully Porous Acetabular Shell with XLPE liner or REDAPT Modular Cup Components (with or without Staple, Slice and Blade Augments), and/or Monolithic Sleeveless Stem, and/or Monolithic Sleeved Stem and are at least 3 months post-implantation at this site.