This is a randomized, single blinded, standard of care controlled clinical trial. All adult patients over eighteen desiring shoulder arthroplasty will be eligible. The study compares pain control and opioid consumption in patients undergoing shoulder arthroplasty between patients receiving liposomal bupivacaine and those who underwent a preoperative inter-scalene nerve block.

Study Design: A randomized single blinded standard of care controlled clinical trial comparing pain management interventions. All patients over age eighteen and scheduled for primary shoulder arthroplasty (SA) a three fellowship trained surgeons will be eligible for inclusion. Patients will be excluded if their medical history presents known allergies or intolerance to dexamethasone, opioid or bupivacaine, substantial alcohol or drug abuse, and pregnancy.

Liposomal Bupivacaine has a refrigerated shelf life of one month the investigational facility. Patients will be sequentially recruited into the randomization process. Liposomal Bupivacaine will be held by the Henry Ford hospital pharmacy up to one month prior to planned shoulder arthroplasty in anticipation of surgery on eligible patients. The sterile solutions will be delivered to and kept by the inpatient clinical pharmacy until the date of surgery and delivered to the operating room at the beginning of a surgical case. The current dose of Liposomal Bupivacaine has been chosen based on previously published data of local infiltrative analgesia with Liposomal Bupivacaine and one published study on Liposomal Bupivacaine efficacy.

The week prior to surgery, patients will be randomized to receive Local infiltration anesthesia (LIA) with Liposomal Bupivacaine, or Inter-scalene nerve block (INB) using a computer generated sequence. The results of randomization will be securely delivered to the anesthesiologist and the surgeon the week prior. The anesthesiologist will view the assigned group to determine if a preoperative INB will be given. Depending on the randomization group either an Liposomal Bupivacaine solution will be delivered to the operating room for local infiltration or the anesthesiologist will perform a preoperative INB.

Patients in the Liposomal Bupivacaine group will receive LIA with 10cc(133mg) of Liposomal Bupivacaine solution dissolved in 20cc of sterile saline before wound closure. The solution will be applied to the wound bed, muscles, and periosteum. The solution will be left unperturbed for five minutes. Thereafter the solution will be suctioned from the wound and the shoulder joint. Incisions will be closed in typical fashion and the wound dressed.The tourniquet will be deflated.

Patients in the INB will receive postoperative ultrasound guided INB. Experienced anesthesiologists will apply all INBs in this study.

Following the procedure pain will be accessed subjectively through visual analog scale and numeric rating scale pain scores, pain diaries given to the patient to record at home, pain summary scores at follow up visits and objectively through narcotic pain requirement. A blind observer will also access outcomes.

Planned Data Analysis:

Means and standard deviations, as well as medians and interquartile ranges will be computed for pain scores.These outcomes will be compared by Wilcoxon rank sum tests. The amount of pain medication and pain scores will be compared by Wilcoxon rank sum tests.

Inclusion Criteria:

• Patients over the age of 18 scheduled for primary shoulder arthroplasty by three fellowship trained surgeons will be eligible for inclusion

Exclusion Criteria:

• Patients will be excluded if their medical history presents known allergies or intolerance to dexamethasone, opioid or bupivacaine, substantial alcohol or drug abuse, and pregnancy.

Sixty patients were recruited for the study. Three patients declined to participate and were excluded before randomization. The remaining 57 patients were randomized with 31 patients in the INB group and 26 patients in the LB group. No patients were lost to follow-up. There were no statistical differences in any demographics between the 2 groups

Use of the VAS, which is a simple one-dimensional analog rating scale, to assess the patients subjective pain level. Patient compliance is a limitation, with maintenance of pain dairies decreasing as time from surgery progressed.