Risk Factors for CRPS

Major risk factors for CRPS

Based on scientific studies, certain risk factors are more common than others. Here are the ones to pay close attention to:

• One of the clearest findings is that CRPS develops more often in women than in men. Some reports suggest the risk is especially higher among postmenopausal women. Why? We don’t fully know. Hormonal differences, vascular responsiveness, immune functions, or nerve repair capacities may differ between genders. However, the bottom line is that being female is a recognized risk factor.
• Most CRPS cases begin after some type of injury. But not all injuries are equal when it comes to risk. Some kinds of damage appear more risky than others, including fractures (especially of the wrist or ankle), dislocations and intra-articular fractures, crush injuries or blunt force trauma, surgery, and multiple injuries. However, while these injuries are common triggers, only a small fraction of people with these injuries go on to develop CRPS.
• One interesting risk factor is how painful the injury is in the early days. Some studies show that when patients report high pain scores (i.e., five or more out of 10) in the first few days after surgery or injury, the risk of developing CRPS increases. This suggests that the way the nervous system reacts immediately after trauma can influence whether CRPS develops.
• Keeping a limb immobile for a long time (like in a tight cast or splint) appears to add to the risk. Some studies point out that long immobilization, especially of joints, can impair nerve input, blood flow, or circulation, making the region more vulnerable. For example, wrist fractures that are immobilized for long periods of time, or casting that’s too tight, have been linked to greater CRPS risk.
• Age as a risk factor is less consistent, but more recent studies indicate that older patients may have a somewhat higher risk, particularly after surgery. One study found that in patients after surgery, older patients faced an increased CRPS incidence in mid- to late-postoperative periods.
• Certain medical and biological traits can set the stage for higher vulnerability. These include poor nerve health, autoimmune or inflammatory diseases, smoking/vascular disease/poor circulation, and genetic or familial disposition.
• While these are more controversial or weaker as direct link factors, many researchers believe that psychological or emotional stress can interact with biological factors to raise the risk of CRPS. Some studies suggest that preexisting anxiety, depression, or psychological stress can modestly increase the risk, but the evidence is often weak or mixed. Other studies find that catastrophizing (thinking that the pain will be unbearable) or high emotional distress can influence how the nervous system responds. Psychological stress is likely a modifier and not a primary cause. In other words, stress can worsen or amplify processes, but it probably doesn’t, on its own, cause CRPS.

Recent research continues to refine the understanding of risk. One 2024 study of patients after surgery (especially orthopedic surgery) looked at what they called “dynamic risk factors”, those that change over time. Key findings included:

• Age and female gender remained significant risk factors.
• Patients who engaged in manual labor had a higher CRPS risk at 6 and 12 months.
• More complex fractures and internal fixation (surgical hardware) may increase the chances.
• Patients with osteoporosis showed a higher risk mid to late in recovery.
• Psychological measures (such as anxiety and depression scores) correlated with CRPS incidence.
• Early physical therapy or occupational therapy might help reduce risk (though this remains to be studied more fully).

These findings reinforce the idea that CRPS risk is not static but changes as healing proceeds, and that medical and rehabilitative management may influence risk.