Total should arthroplasty is recommended for the treatment of shoulder arthritis that causes severe pain and loss of function. Successful shoulder arthroplasty is a technically demanding procedure because of lack of intrinsic stability of the glenohumeral joint. The tension of the rotator cuff and glenohumeral capsule must be balanced for mobility and stability. Attention to important anatomic landmarks and glenohumeral relationships ("pearls") minimizes the risk of complications ("pitfalls").