Inclusion Criteria:

• Primary glenohumeral arthritis,
• Intact rotator cuff,
• No important glenoid bone loss (cf exclusion criteria),
• Patients between 65 and 85 years old
• Informed Consent as documented by signature (Appendix Informed Consent Form).

Exclusion Criteria:

• B2 glenoid with > 80% posterior humeral head subluxation or greater 25 degrees neoglenoid retroversion,
• B3 and C type glenoids,
• Full thickness rotator cuff tear,
• Acute or malunited proximal humeral fracture,
• Chronic locked dislocation
• Rheumatoid arthritis,
• Revision surgery or surgical antecedents,
• Tumors,
• Axillary nerve damage,
• Non-functioning deltoid muscle,
• Glenoid vault deficiency precluding baseplate fixation,
• Infection and neuropathic joints,
• Known or suspected non-compliance, drug or alcohol abuse,
• Patients incapable of judgement or under tutelage,
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, contraindication for CT scan etc. of the participant,
• Enrolment of the investigator, his/her family members, employees and other dependent persons.