Nonunion of the First Sternocostal Synchondrosis Accompanied by Sternoclavicular Joint Synovitis

Injury to the sternocostal synchondrosis of the first rib is quite rare. We report one such case in a 50-year-old man with nonunion of the first sternocostal synchondrosis accompanied by synovitis of the sternoclavicular joint. He first underwent arthroscopic surgery of the left sternoclavicular joint. Postoperatively, the patient's symptoms decreased by half, but another pain and crepitus at the inferior lateral portion of the sternoclavicular joint developed. Since MRI and functional CT reexaminations revealed nonunion of the first sternocostal synchondrosis, resection arthroplasty of the first sternocostal joint was performed. This resulted in immediate resolution of the symptoms. At 2-year follow-up, his symptoms disappeared entirely with no limited range of motion of the shoulder.