148 patients who underwent total knee arthroplasty (TKA) were randomized to receive either zolpidem to help induce and maintain sleep, or a placebo to take orally at bedtime until the 14th postoperative day (POD). The purpose if the study was to compare sleep efficacy and pain levels between the groups to determine if sleep quality affects early TKA outcomes. The results indicated that patients who were prescribed zolpidem had significantly greater sleep efficacy, and also reported significantly lower VAS pain scores for pain at rest, overnight and on ambulation when compared to the placebo group on POD 14. Additionally, opioid analgesic and antiemetic consumption, the incidence of postoperative nausea and vomiting, and patient satisfaction were all significantly better in the zolpidem group by the completion of the study.