There are clear clinical indications for the use of the total and reverse shoulder replacements in patients younger than 70 years old and they are based on cuff integrity and shoulder function. However, the decision to use the total shoulder implant or the reverse total shoulder implant in patients over 70 yrs old with end-stage glenohumeral (shoulder) arthritis and an intact rotator cuff is based on surgeon's preference. There are no studies comparing pain relief for these two implants in this patient population. So this study will randomize 34 patients to either total or reverse shoulder replacements. These individuals must meet the clinical criteria to be a candidate for either implant.