Dempsey AL, Mills T, Karsch RM, Branch TP: Maximizing total end range time is safe and effective for the conservative treatment of frozen shoulder patients. Am J Phys Med Rehabil 2011;90:738-745. Objective: The purpose of this retrospective cohort study was to compare range of motion, subjective outcomes, and the prevalence of reoperation in groups of frozen shoulder patients with either low or moderate/high irritability treated with the same total end range time-maximizing protocol. Design: A total of 36 patients were treated with the total end range time-maximizing protocol (12 patients with low irritability and 24 patients with moderate/high irritability). American Shoulder and Elbow Society Standardized Shoulder Assessment Form (ASES) scores and external rotation and abduction were recorded before and after the rehabilitation protocol and were compared between the two groups. Results: For both groups, external rotation and abduction of the involved shoulder significantly increased from pretreatment to posttreatment, and the posttreatment external rotation and abduction of the involved shoulder did not differ from those of the uninvolved shoulder. There were no differences between the groups in either external rotation (P = 0.71) or abduction (P = 0.46). ASES scores were significantly lower and pain scores were significantly higher for the moderate/high irritability group both before and after treatment than for the low irritability group; however, the moderate/high irritability group demonstrated significantly greater gains in both ASES and pain scores. One patient in the low irritability group underwent a lysis of adhesions. Conclusions: We conclude that a total end range time-maximizing rehabilitation protocol is a safe, effective treatment option for patients with frozen shoulder.