Complex Regional Pain Syndrome (CRPS) is a highly painful condition with heterogeneous clinical manifestations, presenting significant challenges for both clinicians and patients. It typically emerges following an initiating trauma or surgical intervention. The incidence of CRPS ranges from 5 to 26 per 100,000 individuals [1]. Women being affected more frequently than men [1,2]. CRPS typically appears 4 to 8 weeks after the initiating event and is marked by pain that is disproportionate to the initial cause [3]. Although the underlying mechanisms are not fully understood, dysfunction in the central and peripheral nervous systems is thought to be a major factor [4].

The primary symptoms of CRPS include pain localized to the distal extremities, often following a glove-and-stocking distribution. Additionally, patients experience sensorimotor, autonomic, and trophic symptoms, further complicating clinical assessment. Notably, fractures account for approximately 45 % of initiating causes, emphasizing their role in the onset of the condition [2]. CRPS is classified as Type 1 and Type 2 (with major nerve damage, traditionally called causalgia). Despite minimal clinical or therapeutic differences, this classification persists under International Association for the Study of Pain (IASP) guidelines.

A large-scale study has reported that several factors may increase the risk of CRPS. These include female sex, Caucasian ethnicity, high socioeconomic status, depression, headaches, and substance use disorder. The presence of these additional conditions has been associated with a greater susceptibility to CRPS, though the precise mechanisms underlying these correlations remain to be fully elucidated [5]. Psychiatric disorders have been widely recognized as potential risk factors in several studies, with post-traumatic stress disorder and anxiety being particularly associated with an increased likelihood of CRPS onset [6].

Fractures, sprains, surgical procedures, and carpal tunnel syndrome are recognized as potential risk factors for CRPS onset. One study reported that the risk of developing CRPS in patients with distal radius fractures was 0.19 %, highlighting the rarity of its occurrence in this specific population [7]. The increased susceptibility of female patients to CRPS may be partially attributed to a higher predisposition to depression, which has been explored as a potential contributing factor. Both angiotensin converting enzyme inhibitors (ACEI) use and asthma have been identified as potential risk factors for CRPS development.

Post-fracture extremity immobilization may serve as a risk factor for CRPS development. Experimental studies conducted on rats have demonstrated that immobilization is associated with an enhanced inflammatory response and an increase in nociceptive mediators, suggesting a potential mechanistic link between prolonged limb restriction and CRPS onset [8]. Human studies show that brief immobilization reduces motor cortical excitability, indicating a neuroplastic, central-sensitization pathway by which immobilization may facilitate CRPS [9].

The term CRPS was established and conceptualized by the IASP in 1994 [10]. However, this concept had a low specificity in diagnosing CRPS [11]. The new diagnostic method, which evaluates pain/sensation, vasomotor, sudomotor/edema, and motor/trophic symptoms, has improved specificity rates in CRPS diagnosis. This approach marked a milestone for the Budapest criteria, which are now widely used as the current standard for diagnosis [12].

Beyond biological and trauma related mechanisms, psychosocial factors also shape CRPS risk. Pain catastrophizing, a maladaptive cognitive pattern marked by pain magnification and helplessness, increases pain perception, drives central sensitization, and often coexists with conditions like frozen shoulder or chronic regional pain syndromes, pointing to shared neuropsychological pathways. These observations argue for integrative assessment that includes both biological and psychological dimensions [[13], [14], [15]].

This study aimed to investigate demographic, treatment-related, and comorbidity-related risk factors for CRPS after distal radius fracture using conventional statistical analyses in a retrospective case–control design.