Pain management in pediatric patients presents a difficult challenge. Unlike adults, pediatric patients often cannot communicate their pain management needs clearly. Adequate pain control after surgery is pivotal for these patients in order to prevent negative physiologic and psychologic complications and to improve surgical outcomes. There is an ongoing shift away from the use of opioids in the post-operative setting due to both their negative side effects and their high potential for dependence and abuse. A variety of new techniques of multimodal pain management have been developed and utilized in elective orthopaedic procedures. Injection of local anesthetics is becoming a widely popular technique utilized in adult arthroplasty. This technique blocks pain directly at the site of injection, and therefore can improve post-operative pain while minimizing side effects. Evidence has demonstrated this technique to be both safe and effective, resulting in reduced opioid consumption post-operatively. However, this technique has not been studied for use in pediatric patients, a population in which reduced narcotic use is equally, if not more important than in adult patients. This study is a prospective, randomized controlled trial with 2 parallel arms. The goal of this study is to assess the efficacy of a surgical-site pain injection administered in pediatric patients with cerebral palsy undergoing major hip surgery. Patients who are scheduled to undergo surgery will be randomized to either intervention (injection of a pain cocktail) or placebo (injection of normal saline). The pain cocktail includes three medications: ropivacaine (a local anesthetic), ketorolac (an anti-inflammatory medication), and epinephrine (a medication to constrict blood vessels and increase the duration of action of any co-administered medications). A surgeon who is blinded to treatment group will administer the injection at the end of the procedure, prior to the patient waking from anesthesia. The injection is in addition to our typical multi-modal pain control protocol, which includes epidural anesthesia, acetaminophen, anti-inflammatories, oral narcotics and anti-spasmodic agents. Patients will then be monitored post-operatively and pain medication consumption (both while in the hospital post-operatively and for the first two weeks following discharge), patient-reported and/or nurse-recorded pain scores, length of hospital stay, and adverse effects will be recorded. At the first post-operative visit, patients' parents will be asked to complete a survey designed to assess parent satisfaction with their child's pain management after surgery. Patients, parents, and surgeons will be blinded to treatment group allocation. Data will be collected while the patient is in the hospital, after surgery (average duration 3-4 days), and at the first post-operative visit two to three weeks after surgery.