Intra-articular Morphine and Clonidine Injections for Pain Management in Hip Arthroscopy

Background:

Over the last few decades, the use and safety of arthroscopic hip surgery has considerably improved though the evolution and development of arthroscopic imaging and instrumentation (Lynch et al., 2013). There is still a considerable amount of room for growth and research in comparison to arthroscopic knee and shoulder surgery, which have been around much longer. One area which needs attention is postoperative pain management for patients undergoing hip arthroscopy. The benefits to controlling postoperative pain range from improved patient comfort and decreased time of recovery to decreased narcotic medication usage and reduced cost of care (Ramsay 2000).

Many studies on the use of morphine injections into the joint after arthroscopic knee surgery have demonstrated effectiveness in reducing both patient reported pain and narcotic medication usage after surgery (Stein et al., 1991; Yari et al., 2013; Zeng et al., 2014). Furthermore, studies have shown that joint injections of clonidine improve the pain relieving effect of morphine when the two are used in combination (Joshi et al., 2000). While there is considerable evidence supporting the use of joint injections of morphine for knee surgery, very little has been cited for such use in hip arthroscopy (Lavelle et al., 2007). The purpose of our study is to better assess the effectiveness of morphine and clonidine joint injections in reducing patient reported pain and narcotic medication usage after hip arthroscopy.

Protocol:

Participants in this study will be part of a trial for the use of a morphine and clonidine joint injection during hip surgery. Participants will be randomly selected to either receive a standard dose of morphine and clonidine or normal saline solution through a joint injection. The normal saline will have no active drug ingredients. In either case the injection will occur at the conclusion of surgery. The joint injection is the only change to the medical care that will occur for patients who decide to participate in this study. Pain levels will be monitored and treated after surgery, and all pain management after surgery will follow the normal standard of care. Additionally, participants will be asked to fill out a brief questionnaire before and after surgery. All patients will be sent home with a short diary that will allow them to record their medication usage, pain scores, and potential side effects in the week following surgery. The diary with this information will be returned when the patients come back for their standard-of-care two week follow-up appointment.

No additional visits or appointments beyond what the procedure already entails are needed to participate in this study.

The treatment (morphine/clonidine or normal saline injection) will be chosen by chance, like flipping a coin. Neither the participant nor the study doctor will choose which treatment the patient gets. There will be an equal chance of being given either treatment. Neither the participant nor the study doctor will know which treatment is assigned.

Morphine and clonidine are FDA-approved drugs being used in a non-approved context (hip injection). All standard of care procedures will take place to ensure patient safety during and after surgery, while the patients are in the outpatient surgical center. All adverse events will be properly documented and reported to the IRB.

Data Management:

Data points include age, sex, height, weight, tobacco use, VAS pain scores, discharge times, duration of surgery, discharge criteria score, medication use, and scores from the QoR-15 survey. All information that includes personally identifying information, such as name or medical record number, is not entered into the database with the medical information. Identifying information is only entered into a separate database that links the patient to an arbitrary study number.

Statistical analysis of the data will include a Student's T-Test, non-parametric Mann Whitney test, and chi-square test. If there is substantial data missing for a subject, which would be otherwise essential for analysis, the subject's information for that particular analysis will be excluded. To the best extent possible, data that can be interpolated will be utilized.