The efficacy of ascorbic acid in the prevention of complex regional pain syndrome (type 1) following distal radial fracture

Abstract

Complex regional pain syndrome (CRPS) is a common problem presenting to orthopaedic surgeons or pain therapists, most frequently encountered following trauma. The cardinal features are of pain, hypersensitivity, vasomotor instability and joint stiffness. The exact cause remains unproven, however an exaggerated inflammatory response and free radical induced cellular damage has been proposed. A small number of previous studies have highlighted a potential role for antioxidants in the prevention of the condition. Over the last three decades pain researchers have developed and agreed on a set of modified International Association of the Study of Pain (IASP) diagnostic criteria. Orthopaedic researchers have developed their own criteria that have been subject to much debate as to their validity. The diagnosis of CRPS in two hundred and sixty-two patients from a previous study have been reanalysed using the Atkins and modified IASP diagnostic criteria of Bruehl. The incidence of CRPS was similar using either criteria (Bruehl 20.61% vs. Atkins 22.52%). Using the Bruehl criteria as a gold standard, there was strong diagnostic agreement (K = 0.79, sensitivity = 0.87, specificity = 0.94). Two hundred and eleven patients who had sustained an isolated distal radial fracture were recruited for a prospective double-blinded randomised control trial to assess the efficacy of five hundred milligrams of ascorbic acid in order to prevent CRPS. Using an intention to treat analysis one hundred and ninety-six were reviewed at a minimum of nine weeks. There was no significant difference in the incidence of CRPS (chi-squared=1.196, p=0.305) or the incidence or severity of the individual features of the condition between the two treatment groups. The results of this study suggest that prophylaxis with ascorbic acid does not prevent the occurrence of CRPS when diagnosed with validated criteria following a distal radial fracture.

Date of Award	2011
Original language	English