Can vitamin C prevent complex regional pain syndrome in patients with wrist frac

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J Bone Joint Surg Am. 2007 Jul;89(7):1424-31.

Can vitamin C prevent complex regional pain syndrome in patients

with wrist fractures? A randomized, controlled, multicenter dose-

response study.

Zollinger PE, Tuinebreijer WE, Breederveld RS, Kreis RW.

Department of Surgery, Red Cross Hospital, Beverwijk, The

Netherlands.

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.