160 patients with osteoarthritis undergoing total knee replacement were enrolled in this study to compare different combinations of medications as periarticular analgesic injections designed to reduce postoperative pain. Patients were separated into four treatment groups; all the groups received ropivacaine, and epinephrine, and additionally, group A received ketorolac, and clonidine; group B received ketorolac; group C received clonidine and group D was the control group. The results suggest that groups A and B provide the best pain management according to outcome measures assessed by patients and nurses, however physiotherapists assessed group C as having the lowest pain. All other functional and clinical outcomes were similar between treatment groups.