A Dichotomous Pain Scale Reduces Post-Operative Opioid Consumption in Outpatient ACL Surgery: Results from a Prospective Randomized Controlled Study

Background/ Aim This study is a prospective, randomized controlled clinical study investigating the effect of using a dichotomous pain scale on post-operative opioid use in patients undergoing anterior cruciate ligament (ACL) reconstruction compared with the standard of using a 10-pt VAS scale. The primary objective was to determine whether the use of a dichotomous pain scale would reduce the consumption of opioids within the first two weeks after surgery.

Twenty-nine patients undergoing outpatient ACL reconstruction were randomly assigned to either the Binary (n=14) or Scale (n=15) group and completed a survey every day for two weeks after surgery. The Binary group was asked whether their pain was “tolerable” or “intolerable.” The Scale group was asked to rate their pain on a scale from zero to ten, as per standard of care.

Patients in the Scale group on average consumed approximately twice the number of morphine milligram equivalents per day than the Binary group (p=0.03). Two weeks after surgery, there was no significant difference between patient satisfaction nor average knee range of motion between groups (p=0.63, p=0.08).

The results from this study suggest that using a dichotomous tolerability-based pain scale instead of the NPRS could serve as one strategy to reduce opioid use in the post-operative period. Competing Interest Statement The authors have declared no competing interest. Clinical Trial The trial was registered with clinicaltrial.gov (NCT07065266). The study did not, based on our research director's analysis, initially meet the criteria for registration of a clinical trial because it was felt that: Specifically, per decision tree requirements-- the study does not receive NIH funding, does not involve the study of a drug, biologic, or device, and may not be considered an interventional trial as it involves randomizing patients into different survey groups rather than administering a therapeutic intervention. Clearly, we obtained IRB approval from our institution's IRB and all patients underwent the informed consent process and signed informed consent forms prior to participating in the trial. We subsequently retroactively registered the clinical trial at clinical trials.gov. Funding Statement The author(s) received no specific funding for this work. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Institutional Review Board approval from Stanford University was obtained for Protocol #45010 on April 19th, 2018. Patients provided written, informed consent to participate in this study. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Funding: None. Disclosures: We have no relevant disclosures or conflicts of interest to report. Institutional Review Board approval was obtained for Protocol #45010 on April 19th, 2018. Patients provided written, informed consent to participate in this study. Data Availability All relevant data are within the manuscript and its Supporting Information files