A new Mayo Clinic study presented today at the annual meeting of the American Academy of Orthopedic Surgeons in Las Vegas, concludes that those 50 and younger who experience chronic shoulder pain related to arthritic changes in the glenohumeral (shoulder) joint can benefit markedly in terms of pain relief and improved mobility from shoulder joint replacement surgery. The procedure is known as arthroplasty. Typically, arthritic degeneration of the shoulder joint is expected in people 65 years and older. How joint replacement affects a younger patient group was not known until this Mayo study.