Arcos Revision Stem: Evaluation of Clinical Performance

Primary Endpoint: survivorship and revision rate up to 5 years post-operatively Secondary Endpoints: Stability and Fixation of Arcos Hip by radiographic assessment, Relationship between bone defect level and survivorship, Oxford Hip Score and Harris Hip Score post-operative, Adverse events, complications. Case Report Forms: Demographic Data, Paprosky Acetabular/Femoral Defects, Operative Data, Oxford Hip Score, Harris Hip Score, Collection of X-rays, Radiographic Evaluation form, Adverse Events, Revisions, Lost to Follow-up, and Protocol Deviations 200 patients: 100 with BoneMaster HA, 100 without BoneMaster HA. Up to 10 sites globally will be used to fulfill enrollment in this study. All cases enrolled will be those implanted with either the Cone, Broached, or Calcar Proximal Body and one of the five distal options (Slotted, Bullet-tip, Interlocking, STS, or ETO). To be included in the study, a patient must have received a revision total hip arthroplasty with the Arcos system. The Arcos system is to be used in accordance to the indications for use and contraindications detailed in the approved labeling of the device. Study time perspective: Collection of retrospective data in supplement to the data collected in the course of the prospective study to compensate total enrolment goal. This is applicable for 3 sites: Finland, United Kingdom (NHS Sheffield), Spain. All patients enrolled in the study will be followed up as to the same time points for the duration of the study.