Decision of investigational team

This is a prospective multicenter study. Subjects will be implanted with a Conformis Hip System. If the surgeon intraoperatively decides to use the Cordera femoral stem, these patients will also be enrolled in the study and tracked as a subset of the Conformis Hip System patient population.The study sites will be located in the United States. The study subjects will be followed for 10 years post implantation.

Inclusion Criteria:

• Clinical condition included in the approved Indications For Use for the Conformis Hip System and the Cordera Hip System
• Osteoarthritis, as confirmed by the investigator's assessment of disease status at screening visit that warrants a THR procedure
• Willingness to participate in the clinical study, to give informed consent, and to attend all follow-up visits
• > 18 years of age

Exclusion Criteria:

• Simultaneous bilateral procedure required
• BMI > 40
• Poorly controlled diabetes (defined as HbA1c>7 or Investigator discretion)
• Crowe classification of hip dysplasia, grades 2, 3, or 4
• Active malignancy (defined as a history of any invasive malignancy - except non-melanoma skin cancer), unless patient has been treated with curative intent and there have been no clinical signs or symptoms of the malignancy for at least 5 years
• Other lower extremity surgery planned within 1 year of consent to the affected limb Contralateral THR surgery within 3 months pre or post index surgery
• Neuromuscular conditions which prevent patient from participating in study activities
• Active local or systemic infection which precludes THR procedure
• Immunocompromised in the opinion of the Investigator
• Medically diagnosed fibromyalgia or similar conditions that might impact the patient's ability to differentiate source of pain
• Rheumatoid arthritis or other forms of inflammatory joint disease
• Loss of bone or musculature, osteonecrosis, neuromuscular or vascular compromise in the area of the joint to be operated on, to an extent that the procedure is unjustified
• Diagnosed with or receiving treatment for osteoporosis that is likely to confound results in the opinion of the Investigator
• Physical disability affecting the lumbar spine that is likely to confound results in the opinion of the Investigator
• Charcot or Paget's disease
• Inability to complete the protocol in the opinion of the clinical staff due to safety or other reasons
• Participation in another clinical study which would confound results
• Allergy to any of the implant materials

Patients with clinical condition included in the approved Indications For Use for the Conformis Hip System and the Cordera Hip System