Patient genetic heterogeneities acting as indicators of post-operative pain and opioid requirement in orthopedic surgery: A systematic review.

INTRODUCTION: Orthopedic surgical procedures are expected to increase annually, making it imperative to understand the correlations between patient genetic makeup and post-operative pain levels.

METHODS: We performed a systematic literature review using PubMed and Cochrane databases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 299 articles were initially selected, 20 articles remained after title and abstract review, and nine articles were selected for inclusion upon full text review.

RESULTS: Genetic risk factors identified included the A allele of the 5HT2A gene single nucleotide polymorphism, the AA genotype of the ADRB2 gene, the CG genotype of the IL6 gene, the genotypes CT and TT of the NTRK1 gene, genotypes AA and GA of the OPRM gene, and the AA and GA genotypes of the COMT gene. Additional studies in the review discuss statistical significance of other variants of the COMT gene.

CONCLUSION: There have been genetic association studies performed on the patient heterogeneity and its relationship on patient pain levels, but more data need to be collected to understand the clinical utility of stratifying patients based on genomic sequence.