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PubMed This is a summary of 25 peer-reviewed journal articles Updated
Pain Medicine

What Causes CRPS After a Fracture or Surgery?

At a Glance

CRPS after a fracture or surgery is not caused by poor bone healing, but by an abnormal overreaction of the nervous and immune systems. Pain pathways become sensitized, leading to autonomic dysfunction and agonizing pain that remains locked in the "on" position long after the injury has healed.

In this answer

3 sections

01

The Mechanism: Why the Nervous System Overreacts

02

Why Did This Happen to Me?

03

Moving Forward: Retraining the Nervous System

When you experience physical trauma—ranging from a simple wrist fracture or routine surgery to a more severe crush injury—your body’s alarm system sends pain signals to your brain and triggers inflammation to kickstart the healing process. In a typical recovery, this alarm turns off once the tissues and bones have healed. However, in Complex Regional Pain Syndrome (CRPS), the nervous system misfires and stays locked in the “on” position long after the original injury is gone [1][2].

It is crucial to understand that CRPS is not a failure of your bone to heal; rather, it is a rare, abnormal overreaction of the nerves, brain, and immune system [1]. Depending on the original injury, doctors categorize this into two types: CRPS Type I (the most common, where no specific nerve damage is identified) and CRPS Type II (which involves a distinct, confirmed nerve injury) [3].

The Mechanism: Why the Nervous System Overreacts

The development of CRPS involves a complex chain reaction where the body’s normal healing processes go into overdrive. This happens through three main pathways:

  • Central Sensitization: After an injury, the pain pathways traveling from your injury site to your spinal cord and brain can become highly sensitized [1]. The central nervous system effectively turns up the “volume” on pain signals, meaning that even a light touch or mild temperature change is interpreted by the brain as severe, agonizing pain [4][5].
  • Autonomic Nervous System Dysfunction: The autonomic nervous system controls the automatic functions of your body, like blood flow, heart rate, and temperature regulation. In CRPS, this system malfunctions, leading to erratic changes in the affected limb [6][7]. This is why a person with CRPS might experience a hand or foot that dramatically changes color, sweats excessively, or feels freezing cold and then burning hot [8].
  • Neurogenic Inflammation: In a normal injury, immune cells create localized swelling to protect the area. In CRPS, damaged or irritated nerve endings release inflammatory chemicals—such as Substance P (a powerful pain-signaling chemical)—directly into the tissues [9][10]. This creates a vicious cycle of persistent swelling, redness, and immune system activation that further irritates the nerves [11][12].

Why Did This Happen to Me?

It is incredibly frustrating to suffer a devastating chronic pain condition from a routine break, especially when you see others heal perfectly from the exact same injury. While doctors do not fully understand why the nervous system overreacts in some patients but not others, research has identified several risk factors that make someone more susceptible:

  • Biological Sex and Age: Research consistently shows that older age and being female are significant risk factors for developing CRPS after a traumatic event like a distal radius (wrist) fracture [13][14].
  • Genetics: Emerging evidence suggests that specific genetic variations might create a “permissive background” for CRPS [15]. This means some people are born with an immune or nervous system that is naturally more prone to overreacting to trauma [16].
  • Immobilization and Treatment Factors: How an injury is treated can impact the risk. Prolonged cast immobilization is a widely recognized predictor for CRPS development [13][17]. Furthermore, for wrist fractures, the specific surgical technique matters; for example, using an external fixator has been linked to a higher risk of CRPS compared to a standard internal plate [18].
  • Other Medications and Health Factors: Certain medications, such as ACE inhibitors (often used for blood pressure), have been associated with a higher risk of developing CRPS following a fracture [19][20]. Conversely, early active treatment approaches (like guided home exercises) [21], and potentially taking daily Vitamin C supplements immediately following a wrist fracture, have been linked to a lower incidence of the condition [22][23].

Moving Forward: Retraining the Nervous System

Because CRPS is driven by a nervous system overreaction rather than ongoing bone damage, treatment requires a different approach than standard injury recovery. Multidisciplinary care is essential. Instead of waiting for a structural fix, therapies often focus on targeted nerve medications, sympathetic nerve blocks, and specialized physical therapy like graded motor imagery or mirror therapy [24][25]. These techniques aim to safely “retrain” the brain, calm the autonomic nervous system, and gradually dial down the pain volume, offering a path forward for patients navigating this challenging condition.

Common questions in this guide

Is CRPS caused by my bone failing to heal properly?
No, CRPS is not a failure of bone or tissue healing. It is a rare overreaction of your nervous and immune systems where pain signals get locked in the "on" position even after the physical structures from the original injury have healed.
Why do some people get CRPS after a minor fracture while others don't?
While the exact reason isn't fully understood, certain risk factors make some individuals more susceptible. These include being female, older age, specific genetic variations, prolonged cast immobilization, and taking certain medications like ACE inhibitors.
What is the difference between CRPS Type I and CRPS Type II?
Both types involve an overreacting nervous system and cause similar severe pain. The difference is that CRPS Type I occurs without a specific, identifiable nerve injury, whereas CRPS Type II involves a distinct and confirmed injury to a specific nerve.
Why does my injured limb suddenly change color and temperature?
These symptoms are caused by autonomic nervous system dysfunction. The system that normally controls automatic bodily functions, like blood flow and temperature regulation, malfunctions in CRPS. This leads to erratic changes in your limb's color, temperature, and sweating.
Can the nervous system be retrained to stop CRPS pain?
Yes, because CRPS is a nervous system issue, treatments often focus on safely retraining the brain. Pain management specialists use targeted nerve medications, sympathetic nerve blocks, and specialized physical therapies like mirror therapy and graded motor imagery to dial down the pain.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Given that my CRPS is driven by a nervous system overreaction, what nerve-targeting treatments or specialized therapies (like mirror therapy or graded motor imagery) should we prioritize over standard bone healing protocols?
  2. 2.Could any of my current medications, such as ACE inhibitors, be contributing to my symptoms, and should we review them?
  3. 3.What specific signs of autonomic nervous system dysfunction—like temperature or color changes—should I be tracking at home to help you adjust my treatment plan?
  4. 4.Do my symptoms point more toward CRPS Type I or Type II, and do I need electrodiagnostic testing to check for an underlying nerve injury?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

Related questions

Are Opioids Effective for CRPS Nerve Pain?Can CRPS Go Into Full Remission? Prognosis ExplainedDoes Complex Regional Pain Syndrome (CRPS) Spread?Can Vitamin C Prevent CRPS After Surgery or Fracture?How Does IV Ketamine Infusion Therapy Treat CRPS?How Does Mirror Therapy Work for CRPS?How Does Weather and Temperature Affect CRPS Pain?Is CRPS Type 2 More Severe Than Type 1? | Inciteful MedExercising with CRPS: Should You Push Through Pain?How to Tell if a CRPS Sympathetic Nerve Block WorkedWhat Conditions Are Commonly Mistaken for CRPS?SCS vs DRG Stimulation for CRPS: What's the Difference?Why Are Bisphosphonates Used for CRPS?Why Does a CRPS Limb Turn Cold?

References

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This page provides educational information about the biological mechanisms and risk factors of CRPS following an injury. It is not intended as medical advice. Always consult your pain specialist or physician to discuss your specific symptoms, history, and treatment options.

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