Background: Osteoarthritis of the sternoclavicular (SC) joint is a rare condition that leads to decreased function and persistent pain, ultimately altering the function of the shoulder and keeping individuals from their desired activities. SC resection in the setting of primary and posttraumatic osteoarthritis is the most common surgical treatment for these patients, but midterm results are lacking. Purpose/Hypothesis: The purpose was to assess the clinical outcomes, pain levels, return to sports rate, and survivorship after open SC joint resection in the setting of painful primary SC joint osteoarthritis. We hypothesized that an SC joint resection of maximum 10 mm would result in a significant improvement in clinical outcomes, decreased pain levels, a high rate of return to sports, and a high survivorship. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent SC joint resection (maximum 10 mm) by a single surgeon between the years 2006 and 2013 with minimum 5-year follow-up were reviewed. The following clinical outcomes were collected prospectively during this time period: 12-Item Short Form Health Survey Physical Component Score (SF-12 PCS), American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numerical Evaluation (SANE) score, Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score, and patient satisfaction. Return to sports and pain were assessed through use of a customized questionnaire. Survivorship of SC joint resection was defined as not requiring further surgery on the affected joint. Results: A total of 21 SC joints were treated with resection of the medial clavicle and intra-articular disk and capsulorrhaphy for SC joint osteoarthritis in 19 patients with a mean age of 39.4 years (range, 12.5-66.7 years). At minimum 5-year follow-up, 19 SC joint resections were assessed in 16 of 19 patients (84%) with a mean follow-up of 6.7 years (range, 5.0-10.4 years). All outcome scores improved significantly from pre- to postoperative assessments: ASES (from 54 to 90.5; P = .003), SANE (from 61.8 to 90.4; P = .004), QuickDASH (from 43.1 to 13.8; P = .004), and SF-12 PCS (from 39.8 to 51.3; P = .004). Median satisfaction with surgical outcomes was 9 (range, 2-10), and pain levels improved from a score of 8 out of 10 to 3 out of 10 (scale of 0 to 10 with 0 being pain free and 10 worst possible pain). Of the 13 patients who answered the optional sports participation question, 13 (100%) patients had participated in sports before their injury. A total of 14 patients answered the question on sports participation after injury, with 12 (86%) indicating successful return to sports. Pain at its worst (P = .003) and pain with competition (P = .017) significantly decreased pre- to postoperatively. Resection survivorship at final follow-up was 84.2% at 5 years. We found that 3 patients (15%) had recurrent SC joint pain and were treated with revision surgery. Conclusion: Open SC resection arthroplasty with capsulorrhaphy in the setting of pain for SC osteoarthritis results in significant improvement in clinical outcomes, patient satisfaction, return to sports, and pain reduction at minimum 5-year follow-up.