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

Introduction. Pharmacogenetics evaluates a patient's DNA to determine if a particular drug is expected to have a normal clinical effect, heightened effect, or no effect at all on a patient. It may also predict which patients are most likely to experience side effects from the medications. The purpose of this study was to use pharmacogenetic testing to determine how frequently total knee arthroplasty (TKA) patients have genetic variants to standard postoperative pain medications. We further sought to determine if changing the multimodal program based on these results would improve pain control and reduce side effects. Methods. In this prospective, randomized study, buccal cheek swab samples were collected from 31 primary TKA patients. Pharmacogenetics testing was performed on the samples to examine genetic variants in genes OPRM1, CYP1A2, CYP2B6, CYP2C19, CYP3A4, CYP2C9, and CYP2D6. These genes affect the pharmacodynamics and pharmacokinetics of NSAIDs and opioids. We examined the frequency of a genetic variant to one of the multimodal medications we prescribe including celecoxib, hydrocodone, and tramadol. Subjects included 9 men and 22 women. Patients were randomized to one of two groups: the control group received the standard postoperative pain regimen; the study group received a customized regimen based on the pharmacogenetic results. For the first 10 postoperative days patients recorded pain scores, amount of pain medication taken, and any side effects experienced. Results. Genetic variations to one or more medications in our standard postoperative pain management protocol occurred in 13 of the 31 patients (42%). 8 patients (26%) had a variation of gene CYP2C9 affecting celecoxib. 11 patients (35%) had a variation of gene OPRM1 and/or CYP2D6 affecting the response to hydrocodone. 4 patients (13%) had a variation of gene CYP2D6 that altered their response to tramadol. Of the 31 patients tested, only 18 (58%) had no genetic variants related to the pain medications we routinely prescribe. 8 patients (26%) had variants affecting more than one of the medications. (Table 1, below) Both the average pain levels and morphine equivalents consumed in the first 10 days were higher in the control group than in the study group. Conclusion. 42% of patients in this study demonstrated a pharmacogenetic variant to one of the commonly used multimodal pain medications. Our early data suggests that customizing pain regimens based on this information can help reduce pain and the amount of pain medication used postoperatively. For figures, tables, or references, please contact authors directly

Aims

The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA.

Aims

The purpose of this study was to use pharmacogenetics to determine the frequency of genetic variants in our total knee arthroplasty (TKA) patients that could affect postoperative pain medications. Pharmacogenetic testing evaluates patient DNA to determine if a drug is expected to have a normal clinical effect, heightened effect, or no effect at all on the patient. It also predicts whether patients are likely to experience side effects from medicine. We further sought to determine if changing the multimodal programme based on these results would improve pain control or reduce side effects.