Complex regional pain syndrome type I: incidence and risk factors in patients with fracture of the distal radius.

OBJECTIVE To examine the incidence and predictors of complex regional pain syndrome type I (CRPS I) after fracture of the distal radius. DESIGN Prospective study. SETTING University hospital. PARTICIPANTS A consecutive sample of patients (N=90) with fracture of the distal radius treated by closed reduction and casting. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Occurrence of CRPS I, occurrence of pain, wrist and hand range of motion, radiographic measures, Patient-Rated Wrist Evaluation, Hospital Anxiety and Depression Scale, and Medical Outcomes Study 36-Item Short-Form Health Survey at baseline and 1, 3, 6, and 9 months follow-up. RESULTS CRPS I occurred in 29 patients (32.2%) with a mean delay ± SD of 21.7±23.7 days from cast removal. Univariate analyses found significant differences between patients with CRPS I and patients without CRPS I at baseline for sex (P=.021), socioeconomic level (P=.023), type of trauma (P=.05), pain at rest and activity (P=.006 and P<.001, respectively), wrist dorsiflexion and pronation (P=.002 and P=.001, respectively), finger flexion (P=.047), thumb opposition (P=.002), function of the hand (P<.001), and physical quality of life (QOL) (P=.013). Logistic regression showed that risk for CRPS I was higher in cases of women (odds ratio [OR]=5.774; 95% confidence interval [CI], 1.391-23.966), medium and low energy trauma patients (OR=7.718; 95% CI, 1.136-52.44), patients with a Medical Outcomes Study 36-Item Short-Form Health Survey physical functioning score <40 (OR=4.931; 95% CI, 1.428-17.025), and patients with Patient-Rated Wrist Evaluation pain subscale score >16 (OR=12.192; 95% CI, 4.484-43.478). CONCLUSIONS CRPS I occurs frequently during the third and fourth week after cast removal, especially in women who report severe pain and impairment of physical QOL. Additional prospective studies are required to verify these findings in comminuted and operated fractures of the distal radius.