Pain and Opioid Use Outcome Measures in Knee Arthroplasty Randomized Controlled Trials

Abstract

The primary focus of this thesis is to outline the importance of reporting pain and opioid use as interrelated outcomes either as multicomponent or co-primary endpoints. When more opioids are used, pain intensity can decrease, whereas inadequate analgesia can worsen the pain. Trials that emphasize minimizing opioid use can be successful in minimizing opioid consumption, but patients may still suffer from pain. Similarly, trials that focus on decreasing pain could have increased opioid consumption to manage pain. Currently, many surgical trials report these outcomes as separate entities, which can be problematic as these outcome domains are conceptually interrelated. To our knowledge, no previous studies have evaluated the reporting of these two outcomes as interrelated endpoints, as well as the methods used to report them. As one part of this thesis, we conducted a systematic review to identify pain and opioid use reporting within total knee arthroplasty randomized controlled trials. Our review found that only 2.1% of trials reported these outcomes as either multicomponent or co-primary endpoints. In our secondary analysis, 44.7% of trials reported pain as a primary outcome, whereas 32.3% of trials reported opioid use as a primary outcome. We suggest that future trials consider approaches for combining these outcomes while using appropriate methods to minimize type I and type II error rates. As the second part of this thesis, we report a pilot trial protocol of an ongoing study that evaluates pain and opioid use outcomes in total knee arthroplasty patients. In this trial, pain and opioid use at the patient level are combined, as a state of opioid-free pain control, and serves as an example of a multicomponent endpoint.