# Incidence proportion of complex regional pain syndrome (CRPS) after distal radius fracture: a population-based register study

## TL;DR

This study finds that about 0.2% of people who break their distal radius develop complex regional pain syndrome within a year, with higher rates in younger adults and those who had surgery.

## Contribution

The study provides a population-based incidence proportion of CRPS after DRF, stratified by age, sex, and treatment.

## Key findings

- The 1-year incidence proportion of CRPS after DRF was 0.20%.
- CRPS was more common in surgically treated patients (0.31%) than non-surgical (0.17%).
- The incidence proportion decreased after 2010, from 0.24% to 0.14%.

## Abstract

One of the most severe complications of distal radius fractures (DRF) is the development of complex regional pain syndrome (CRPS). The incidence proportion (IP) of CRPS following DRF varies widely in the literature. Our aim is to report the incidence proportion of CRPS in DRF patients, subgrouping on age, sex, and treatment choice, and secondarily to assess development over time.

Data was extracted from the Danish National Patient Register on patients > 18 years diagnosed with a DRF (S525) in the period 1998–2017.

There were 247,128 DRF in 203,533 patients with a mean age of 61 years. 75% were females. Within 1 year, 493 DRF patients developed CRPS corresponding to a 1-year IP of 0.20% and with an incidence density of 0.57/100,000/year. Median time from DRF to diagnosis was 89 days (SD 73). The IP ranged from 0.01% to 0.39% between age groups with the 30–65-year-olds having the highest incidence proportion. The surgically treated group had an IP of 0.31% and the non-surgical group had an IP of 0.17%. CRPS was slightly more common in women than men (0.21% vs 0.16%). We found a decrease in IP after 2010 from 0.24% to 0.14%.

There was a low IP of CRPS diagnosis after DRF treatment with an observed higher IP in the 30–65-year-olds and in surgically treated patients. We consider this to be a minimum IP due to possible undiagnosed cases, but the overall results may be closer to the clinical reality than previous studies.