Abstract

Abstract

Introduction

Adverse reactions to pain medication and pain can delay discharge after outpatient knee arthroplasty (TKA). Pharmacogenomics is an emerging tool that might help reduce adverse events by tailoring medication use based on known genetic variations in the CYP genes determining drug metabolism. This study was undertaken to evaluate whether pre-operative pharmacogenomic testing could optimize peri-operative pain management in patients undergoing total knee arthroplasty (TKA).

Methods

This prospective, randomized study was performed in adults undergoing primary TKA. Patients in the experimental group underwent pre-operative pharmacogenomic evaluation and medication adjustments. Medications were not optimized for control patients. The Overall Benefit of Analgesic Score (OBAS) at 24 hours post-op was the primary outcome. Postoperative pain scores (VAS scale), total opioid use, time in recovery, and time to discharge were also compared.

Results

76 patients enrolled. 93% of patients had a poor-intermediate phenotype for at least one of four CYP genes. OBAS did not differ significantly between the two groups (4.2 control vs. 4.7 experimental; 95% CI −1.1 to 2.1) and was below the minimum clinically important difference of 2.0 points. Furthermore, there were no differences in any OBAS subscale including pain, satisfaction, or nausea. There were no differences in time in the recovery area or to discharge from hospital, or narcotic use.

Conclusions

Despite many patients having a poor-intermediate phenotype for a CYP gene, pharmacogenomic testing prior to TKA and medication adjustment did not improve anesthesia or pain management outcomes, time to discharge or mean total opioid use after surgery.