This study is a prospective, multi-center, consecutive series study of subjects treated with REDAPT™. The safety and effectiveness of the REDAPT™ revision stem will be assessed over a maximum of 5 years with additional follow up to 10 years to assess outcomes. The objective of this study is to establish if the REDAPT™ stem revision rate is less than 9.8% at 5 years with an observed rate from literature review of 6.5% at 5 year.