Evaluation of the performance and safety of the Catalyst CSR Shoulder System with clinical and radiographic results at multiple time points through 24 months postoperatively This study will be a prospective multi-center study conducted in the United States.

The purpose of this study is to assess the performance and safety of the Catalyst CSR Shoulder System in skeletally mature patients with degenerative disease of the glenohumeral joint where hemi or total shoulder arthroplasty is determined by the surgeon to be the preferred method of treatment. Patients who sign informed consent and meet the inclusion/exclusion criteria will have the Catalyst CSR Shoulder system implanted at participating sites. Data will be collected at baseline (pre-operative), perioperatively, and postoperatively at 3 months, 6 months, 12 months and 24 months. This study is expected to take 36 months to complete.

Inclusion Criteria:

• 18 years of age or older
• Patient must be skeletally mature with degenerative disease of the glenohumeral joint where hemi or total shoulder arthroplasty
• Meets the Catalyst CSR Shoulder System Indications for Use according to approved labeling

Exclusion Criteria

• Has a history of open surgery to index shoulder prior to treatment with the Catalyst CSR system? (history of previous arthroscopic surgery allowed)
• Has a full thickness rotator cuff tear diagnosed by MFI or marked posterior glenoid wear
• Patient is unwilling or unable to comply with the post-operative care instructions, attend follow visits per the study schedule and complete the study assessments (i.e., Pros)
• The patient is a non-English speaker
• In the opinion of the investigator, is it not in the patient's best interest to participate in this study
• Local or systemic infection, or osteomyelitis of the proximal humerus or scapula; if a systemic infection or a secondary remote infection is suspected or confirmed, joint replacement surgery should be delayed until infection is resolved
• Inadequate or malformed bone that precludes adequate support of fixation of the prosthesis
• Osteoporosis
• Neuromuscular disorders that do not allow control of the joint
• Chronic instability, chronic dislocation or deficient soft tissues and other support structures (e.g., brachial plexus or deltoid muscles)
• Vascular insufficiency
• Subject's age, weight or activity level cause the surgeon to expect early failure of the system
• The patient is unwilling to comply or unable to comply with the post-operative care instructions
• Alcohol, drug, substance abuse or other conditions that would affect or impair the patient from complying with post-operative instructions
• Patients with known sensitivity to Co-Cr-Mo alloys typically used prosthetic devices
• Any disease that could adversely affect the function or expected longevity of the implants (e.g., metabolic disorders)