This observational study is conducted in order to evaluate the effectiveness of the primary total shoulder arthroplasty with the Permedica's MIRAI Modular Shoulder Prosthesis System on the general population of patients who are about to undergo this surgery for every indication. Patients requiring a revision shoulder arthroplasty will not be enrolled.

The effectiveness will be evaluated in terms of recovery of shoulder function and stability of the prosthetic implant. The incidence of complications, adverse and serious adverse events will also be studied. Additional study aim is to evaluate a medium/long term survival of the prosthesis.

The duration of the study per single subject is 5 years.

Inclusion Criteria:

• both genders
• at least 18 years old of age
• undergoing a primary total shoulder arthroplasty with MIRAI® Prosthesis System (anatomic or reverse, stemless or stemmed).
• Signed informed consent

Exclusion Criteria:

• Patients requiring a revision shoulder arthroplasty
• Persistent chronic or acute infections and all septic conditions
• Persistent osteomyelitis local or systemic
• Allergy or hypersensitivity to the substances contained in the materials of the implanted components
• Acute or chronic neurological and/or musculoskeletal impairment which compromises the shoulder joint function such as an axillary nerve injury affecting the deltoid muscle
• Inadequate bone structure which cannot guarantee stability to the prosthetic components
• Several vascular, nerve or muscular disorders, which compromise related extremities
• Marked osteoporosis, osteomalacia
• Hypotrophy of the periarticular soft tissues
• Dysmetabolic diseases such as, for example, kidney failure or systemic diseases
• Muscular insufficiency
• Active neoplastic or metastatic diseases
• Any other clinical or physical condition that can invalidate the surgery, the rehabilitation or the prosthesis stability
• Patient unwilling or unable to undergo the rehabilitation or to return to follow-up visits
• Women in pregnancy, childbearing potential or breastfeeding
• Involvement in other ongoing studies or clinical trial.

Patients who are about to undergo a primary total shoulder arthroplasty in daily clinical practice, referring to one of the project investigator at the study site will be proposed to partecipate to the study.