This is a multicenter retrospective longterm clinical outcome study conducted in up to 6 hospitals in France. 502 subjects who have undergone THA with POLARSTEM™ from 2002 to 2005 will be enrolled in this study and clinical and radiographically followed up for at least 10 years. Subjects who have not reached the 10-year post surgery timepoint will be invited to a 10-year post-operative follow-up visit to obtain the clinical and radiographic outcome measures.