The objective of this prospective multicenter cohort study of patients undergoing surgery for glenohumeral instability is to identify the outcomes, and more importantly, the previously unknown predictors of sports function, activity level, general health, recurrent instability symptoms, and surgical failures following surgery. Patient information at the time of the surgery (demographics, validated outcome measures), in addition to the physical exam findings, shoulder pathology at the time of surgery, and surgical treatment will be obtained. The validated outcome instruments are American Shoulder and Elbow Surgeons Score, Western Ontario Shoulder Instability, Kerlan Jobe Overhand Athlete Score, Shoulder Activity Score, and RAND-36. Post-operative physical exam data will be obtained at 6 months after surgery. Patient reported outcomes will be repeated at 2, 6, 10, and 20 years post-operatively. Our multivariable analysis will identify which of the many factors related to the injury, intra-operative treatment, postoperative care, physical patient characteristics, and behavioral patient characteristics contribute to recurrence and poor outcome.