The purpose of this study is to determine if Sidus stem-free shoulder system is safe and effective when used in total shoulder replacement.

The primary objectives of this study are to evaluate the safety and efficacy (defined as follows) of the Sidus Stem-Free Shoulder System in unilateral primary total shoulder arthroplasty.

Safety: Will be evaluated by monitoring the frequency and incidence of device related adverse events or unanticipated adverse device effects (UADEs) in investigational subjects as well as analyzing survivorship using revision or intended revision as an endpoint.

Efficacy: Will be determined by comparing the overall pain and functional performance, survivorship and radiographic success of investigational subjects with those subjects who received the control devices.

Inclusion Criteria:

• Patient must be 22 years of age or older.
• Patient is skeletally mature.
• Patient must have signed the IRB/EC approved informed consent.
• Patient is a candidate for a total shoulder arthroplasty (replacement of humeral head and glenoid).
• Patient has a diagnosis of primary osteoarthritis of the shoulder of grade III or higher.
• Patient has experienced symptoms of shoulder pain and/or loss of function for at least 6 months and has a maximum ASES score of 40.
• Patient has no findings to indicate an etiology of acute trauma, infection, avascular necrosis or inflammatory arthropathy of the operative shoulder.
• Patient has undergone no previous reconstructive shoulder surgery. Acceptable previous shoulder surgeries include arthroscopy, soft tissue repair, or pinning/screw fixation due to a historic fracture.
• Patient is willing and able to comply with the required post-operative therapy as defined in the protocol.
• Patient is willing and able to comply with the required follow-up schedule as defined in the protocol.

Exclusion Criteria:

• Patient is a prisoner.
• Patient is a known current alcohol or drug abuser.
• Patient has a psychiatric illness or cognitive deficit that precluded informed consent.
• Patient has a chronic renal impairment or failure.
• Patient sensitivity to implant materials.
• Patient has a vascular insufficiency due to large or small vessel disease which could inhibit postoperative healing.
• Patient is currently receiving or has received within the last 3 months chronic systemic or inhaled steroids. This exclusion does not apply to those patients with occasional inhaler use due to seasonal allergies.
• Local rash or skin infection around the intended operative site.
• Patients with ongoing Worker's Compensation or third party liability claims related to the operative shoulder.
• Pre-existing contra-lateral shoulder replacement less than 6 months ago.
• Patient who will require a contra-lateral shoulder replacement less than 6 months from the current planned shoulder replacement.
• Patient has evidence of major joint trauma, infection, avascular necrosis, cuff tear arthropathy, chronic dislocation, massive rotator cuff tear, inflammatory arthropathy, or previous shoulder surgery (other than arthroscopy, soft tissue repair, or pinning/screw fixation due to historic fracture).
• Patient has significant muscle paralysis.
• Patient has Charcot arthropathy.
• Patient has metaphyseal bony defects at the bone/implant interface which could inhibit prosthesis fixation.
• Patient has a preoperative computed tomography scans or other radiographic images of the shoulder that showed insufficient glenoid or humeral bone stock to allow for implantation of the prosthesis.
• Insufficient bone stock exists in the presence of metabolic bone disease (i.e. osteoporosis or severe osteopenia), cancer and radiation.
• Patient with severe glenoid deficiency.
• Prior fracture of the operative shoulder with the presence of malunion or non-union.
• Prior tuberosity fracture with the presence of malunion or non-union.
• Patient has an active joint or systemic infection.
• Patient has a life expectancy of less than two years.
• Patient with unacceptably high operative risk.
• Patient unwilling to sign protocol required informed consent.
• Patient is unwilling to complete the protocol required radiographic imaging.
• Patient is unwilling to complete the protocol required follow-up of two years.
• Patient is known to be pregnant.
• Intraoperative findings which indicate insufficient bone stock or local deformities which could inhibit prosthesis fixation. Final assessment of bone quality will be completed intraoperatively upon resection of the humeral head and prior to insertion of the anchor as described in the surgical technique. If there is any doubt regarding bone quality affecting the stable fixation of the anchor, the surgeon must use a stemmed prosthesis.

Reported Adverse Events (AEs) include events from the date each subject was implanted until the date of study closure or date of revision (if applicable).

If a subject experienced more than 1 of a given AE, the subjects are counted only once for that AE. If a subject experienced more than one AE in a system organ class (SOC), the subject is counted only once in that SOC.