Prospective randomized study of the vitamin C effect on pain and complex pain regional syndrome after total knee arthroplasty.

Abstract

Complex regional pain syndrome (CRPS) type I, formerly known as reflex sympathetic dystrophy (RSD) or algodystrophy, is a condition with chronic pain condition following a trauma or surgery. The physiopathology of this syndrome remained incompletely known. Due to the lack of effective curative treatment, prevention of this complication is important. Therefore, we evaluated the efficacy of vitamin C in preventing this complication. Between January 2018 and July 2019, we conducted a prospective randomized study on the efficiency of vitamin C (one group with and one without vitamin C) on prevention of CRPS risk in patients operated in our institution with TKA. Patients with a VAS pain score > 4 performed a three-phase bone scintigraphy. The diagnostic of CRPS was made by using the Budapest criteria associated to a bone scintigraphy. Statistical significance was set at p < 0.05 RESULTS: One hundred fifty-three patients were included in the vitamin C group, 139 in the control group without vitamin C. For the entire cohort, the prevalence of complex regional pain syndrome was 7.9% (23 of 292). The prevalence of complex regional pain syndrome was 3.9% (six of 153) in the vitamin C group and 12.2% (seventeen of 139) in the control group (p = 0.008). After multivariate regression, vitamin C was found to be an independent preventive factor of CRPS and there was a significant difference between the vitamin C group and the control group (relative risk, 0.27; 95% confidence interval, 0.1-0.8; p = 0.015). Taking 1 g per day of vitamin C during 40 days after a TKA reduces the risk of CRPS.