This is a randomized controlled trial with the seleXys PC cup and RM Pressfit vitamys cup in combination with the optimys short stem. Wear rate and migration is assessed with roentgen stereophotogrammetric analysis (RSA) measurements.

Inclusion Criteria:

• Patients with symptomatic arthritis who are candidates for a primary total hip arthroplasty with an uncemented femoral stem as determined jointly by the surgeon and the patient.
• Patients suitable for an uncemented acetabular component in combination with a 36mm femoral head (seleXys PC cup: 52mm, 54mm or 56mm; RM Pressfit vitamys: 52mm, 54mm or 56mm)
• Patients between the ages of 50 and 75 inclusive
• Patients who understand the conditions of the study and are willing to participate for the length of the prescribed follow-up

Exclusion Criteria:

• Patients that require an acetabular cup size which cannot be used in combination with a 36mm femoral head
• Patients that offer no guarantee for regular follow-up controls
• Patients that have a revision surgery
• Patients that have a fracture of the femoral neck or a bone tumour in the area of the femur or pelvis
• Patients that had a previous osteotomy of the femur or pelvis
• Pregnant women or those seeking to become pregnant
• Patients with a history of active infection