Complex regional pain syndrome (type 1): a comparison of 2 diagnostic criteria methods

Complex regional pain syndrome (CRPS) is a common problem presenting to orthopedic surgeons or pain therapists, most frequently encountered after trauma or surgery to a limb. Because of a lack of a simple objective diagnostic test, diagnosis is reliant on clinical assessment. Prospective studies have repeatedly demonstrated a higher incidence than retrospective studies, an observation that has been challenged owing to the lack of uniformity of diagnostic criteria across specialties and workers researching the condition.

A series of 262 adult patients presenting to the Bristol Royal Infirmary with a closed unilateral distal radial fracture were assessed at a mean of 9.47 weeks after their injury by a single clinician (J.A.L.). Each assessment made allowed comparison of the modified International Association for the Study of Pain (Bruehl) criteria for the presence of CRPS with the criteria described by Atkins.

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 (kappa=0.79, sensitivity=0.87, specificity=0.94). Disagreements between the 2 criteria methods were found in 19 patients. The majority of these discordances were due to differences in pain and sensory abnormality assessment.

These findings show that the Bruehl and Atkins criteria are basically concordant. The differences reflect only minor variations in the assessment of pain. Agreement between researchers in the orthopedic and pain therapy communities will allow improved understanding of CRPS.