Impaired bone mineral density in patients with complex regional pain syndrome

Abstract

Complex regional pain syndrome (CRPS) is a debilitating condition characterized by chronic pain and functional limitations, with an unclear etiology. Multiple factors are implicated in its pathophysiology. The objective of this study was to investigate differences in bone mineral density (BMD) between the affected and unaffected feet in patients diagnosed with CRPS. Diagnosis was established using the Budapest consensus criteria. We previously described a technique for assessing focal feet BMD using dual-energy X-ray absorptiometry (DXA), focusing on two regions of interest (ROIs) in healthy subjects. We hypothesized that patients with CRPS would exhibit significantly reduced bone mineral density in the affected foot compared with the contralateral unaffected foot.

Methods: A cross-sectional study was conducted to assess BMD differences between the affected and unaffected feet in patients with CRPS.

Results: A total of 17 patients (15 females and 2 males) were included, with a median age of 58 years (range 29-73). Patients with CRPS exhibited significantly lower BMD in both ROIs of the affected limb compared to the unaffected limb (p < 0.05). The median percentage difference in BMD was -8.4 % (-1.3; -15.9) for ROI 1 and -8.9 % (-3.3; -29) for ROI 2.

Conclusion: Our findings indicate a significant decrease in BMD in the affected limb of CRPS patients as assessed by DXA. Although limited by the small sample size, these results suggest that DXA may serve as a valuable tool for evaluating and monitoring treatment responses in individuals with CRPS, potentially guiding therapeutic interventions aimed at preserving bone health.

Keywords: BMD; Complex regional pain syndrome; DXA.