Outcomes Study of the Trabecular Metal (TM) Reverse Shoulder System

Inclusion Criteria: * Patient is \> 18 years of age; * Patient is skeletally mature; * Patient qualifies for primary or revision unilateral or bilateral reverse total shoulder arthroplasty based on physical exam and medical history including the following: osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, ununited humeral head fracture, irreducible 3-and 4-part proximal humeral fractures, avascular necrosis, gross rotator cuff deficiency or failed total shoulder arthroplasty (both glenoid and humeral components require revision); * Patient is willing and able to provide written informed consent; * Patient is willing and able to cooperate in the required post-operative therapy; * Patient is willing and able to complete scheduled follow-up evaluations/questionnaires as described in the Informed Consent; * Patient has participated in the Informed Consent process and has signed the Institutional Review Board (IRB)/Ethical Review Board (ERB) approved informed consent. Exclusion Criteria: * The patient is a prisoner; * The patient is mentally incompetent or unable to understand what participation in the study entails; * The patient is a known alcohol or drug abuser; * The patient is anticipated to be non-compliant; * The patient has one of the following compromising the affected limb: a significant injury to the upper brachial plexus, paralysis of the axillary nerve or a neuromuscular disease compromising the affected limb which would render the procedure unjustifiable; * The patient has a local/systemic infection; * The patient is known to be pregnant; * The patient has marked bone loss; * The patient has a known sensitivity or allergic reaction to one or more of the implanted materials; * The patient is unwilling or unable to give consent or to comply with the follow-up program.