What is the incidence of complex regional pain syndrome (CRPS) Type I within four months of a wrist fracture in the adult population? A systematic review

Introduction
Complex regional pain syndrome (CRPS) is a severe chronic pain condition, the symptoms of which may develop following trauma to a limb. Despite wrist fracture being a common antecedent, estimates of the incidence of CRPS following this injury vary widely. Our objective was to establish the incidence of CRPS in adults within four months of a wrist fracture, using a systematic review of the literature published since 2010.
Methods
The databases MEDLINE, PubMed, EMBASE, PsychINFO, CINAHL, BNI and AMED were searched for observational studies reporting the incidence of CRPS following a wrist fracture. Inclusion criteria were the use of a validated diagnostic tool to assess for CRPS within four months of the fracture. Randomised controlled trials and clinical trials were excluded, as were data from patients with evidence of prior neurology. Incidence risk was then extracted or calculated. Included studies were assessed for methodological rigour using the Newcastle–Ottowa Scale for assessment of bias.
Results
Nine studies met the inclusion criteria. There was a high degree of heterogeneity in study populations including study setting, fracture management and diagnostic criteria. From the three studies with the highest methodological rigour we determined that the incidence risk of CRPS in adults is between 3.7% and 14% using the Budapest criteria, with an observation of lower rates in conservatively managed fractures.
Discussion
We found evidence that the reported incidence of CRPS is influenced by choice of diagnostic criteria, along with the study location and/or how the fracture is managed.