Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-response study.
BACKGROUND
Complex regional pain syndrome type I is treated symptomatically. A protective effect of vitamin C (ascorbic acid) has been reported previously. A dose-response study was designed to evaluate its effect in patients with wrist fractures.


METHODS
In a double-blind, prospective, multicenter trial, 416 patients with 427 wrist fractures were randomly allocated to treatment with placebo or treatment with 200, 500, or 1500 mg of vitamin C daily for fifty days. The effect of gender, age, fracture type, and cast-related complaints on the occurrence of complex regional pain syndrome was analyzed.


RESULTS
Three hundred and seventeen patients with 328 fractures were randomized to receive vitamin C, and ninety-nine patients with ninety-nine fractures were randomized to receive a placebo. The prevalence of complex regional pain syndrome was 2.4% (eight of 328) in the vitamin C group and 10.1% (ten of ninety-nine) in the placebo group (p=0.002); all of the affected patients were elderly women. Analysis of the different doses of vitamin C showed that the prevalence of complex regional pain syndrome was 4.2% (four of ninety-six) in the 200-mg group (relative risk, 0.41; 95% confidence interval, 0.13 to 1.27), 1.8% (two of 114) in the 500-mg group (relative risk, 0.17; 95% confidence interval, 0.04 to 0.77), and 1.7% (two of 118) in the 1500-mg group (relative risk, 0.17; 95% confidence interval, 0.04 to 0.75). Early cast-related complaints predicted the development of complex regional pain syndrome (relative risk, 5.35; 95% confidence interval, 2.13 to 13.42).


CONCLUSIONS
Vitamin C reduces the prevalence of complex regional pain syndrome after wrist fractures. A daily dose of 500 mg for fifty days is recommended.
Zollinger
P E
PE
Department of Surgery, Red Cross Hospital, Beverwijk, The Netherlands. PE.Zollinger@tiscali.nl
Tuinebreijer
W E
WE
Breederveld
R S
RS
Kreis
R W
RW
D000704:Analysis of Variance; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D016009:Chi-Square Distribution; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D050723:Fractures, Bone / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012019:Reflex Sympathetic Dystrophy / Q000209:etiology / Q000517:prevention & control*; D016896:Treatment Outcome; D014954:Wrist Injuries / Q000150:complications*
D000975:Antioxidants; D001205:Ascorbic Acid