This will be a prospective association study in which we will recruit patients who have experienced single extremity trauma, or who have scheduled elective surgery on a single extremity. HRQoL will be determined at recruitment. We will identify their haplotypes and genotypes for 4 linked SNPs in the coding region of COMT as described by Diatchenko [2]. Patients will receive follow-up at 3 and 6 months following trauma or surgery. Individuals who report either neuropathic pain or a reduced HRQoL score will be more closely examined, in order to identify CPSP or CRPS. Statistical analyses will be performed to determine whether haplotypes are associated with the development of either condition, and to determine the strength of this association.