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Diagnosing Post-Op Pain: CRPS or Reaction to Implanted Hardware?

A patient case was posted in November 2019 to the Healthcasts peer-to-peer community, for which 21 unique opinions were contributed by Healthcasts members practicing Surgery, Orthopedics, and other specialties. The following is a synopsis of their consensus treatment plan and recommendations.

A podiatrist refers a patient to you who had foot surgery with hardware for hallux valgus deformity. She has been compliant with resting the foot and is now 3 months post-op, but complaining of burning pain, worse at night, with hyperalgesia, hyperemia, and edema in the surgery site and distal to it. Which of these signs or symptoms are contributory to a diagnosis? What treatment would you recommend?


Jeffrey Gudin, MD
Clinical Associate
Professor, Anesthesiology
Rutgers New Jersey Medical School
Newark, NJ

Total respondents: 21

Case assessed: December 2019


This patient may be experiencing these symptoms as a result of her recent surgery. Hyperemia or swelling may point to a low-grade infection, pin migration, or bone nonunion. Hyperalgesia is typically seen when there is an injury or pathology affecting the nervous system. This can be due to local nerve injury or compromise to the spinal cord or nerve root which manifests as heightened or altered pain sensitivity. Other possible symptoms include allodynia, or pain due to a stimulus that does not normally provoke pain, or hyperpathia, an exaggerated reaction to pain in the affected area that is either more intense or longer-lasting than expected.


43% of the Healthcasts Community respondents concluded that this patient may be experiencing complex regional pain syndrome (CRPS), type 1, causing her to feel burning pain.

Many respondents surmised that the hardware may be compressing a local nerve in the foot causing the patient to experience these symptoms. Others felt that an infection developed during the implantation.

Additional reasons to consider for the patient’s symptoms were hardware failure, cellulitis and osteomyelitis.  


Determining the cause and diagnosis of the patient’s symptoms is often clinically challenging. A comprehensive workup might include bloodwork or culture to rule out infection, an MRI, X-ray, EMG/NCV, and possibly a lumbar sympathetic block to determine potential sympathetic involvement. Following this, a treatment plan can be developed. Often a diagnosis of CRPS is one of exclusion, and consideration should always be given as to whether the implanted hardware is causing the patient’s symptoms. Following a thorough workup is complete, respondents offered antibiotic therapy to treat infection, as well as neuropathic analgesics such as a gabapentinoid (Neurontin, Lyrica) or tricyclic antidepressant or SNRI (eg. Duloxetine/Cymbalta) to help relieve the patient’s pain and burning sensations. About one third of the respondents also felt that the patient would benefit from physical therapy.


The treatment of hallux valgus deformity includes both conservative and surgical treatments. Non-operative management is usually based on footwear modifications, orthotics and analgesia, but has been shown to have a limited role in preventing progression. Surgical correction is often indicated once conservative treatment has failed. Unfortunately, postoperative complications exist, and when present, can be a significant source of distress and chronic pain.

Complex regional pain syndrome is a challenging condition that includes a broad spectrum of sensory, autonomic, and motor features predominantly in extremities recovering from a surgery or trauma. This condition was previously known as reflex sympathetic dystrophy, Sudeck’s atrophy, shoulder-hand syndrome, or causalgia. There are 2 types or classifications of CRPS, based on whether there is a defined nerve injury or not (Type 2 versus 1, respectively). There are acute, dystrophic and atrophic stages of CRPS with burning pain and increased sensitivity to touch being the most common early symptom which outlast the expected normal healing period. Swelling and joint stiffness usually follow, along with increased warmth and redness in the affected limb. There may be faster-than-normal nail and hair growth and excessive sweating. After a few months, the dystrophic phase is characterized by cooler skin temperature, brittle fingernails and more widespread pain and stiffness.

CRPS is a syndrome characterized by a continuing (spontaneous and/or evoked) regional pain that is seemingly disproportionate in time or degree to the usual course of any known trauma or other lesion. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings. The syndrome shows variable progression over time.

CRPS treatment can be very challenging and a subset of all CRPS patients may be described as refractory to all standardized treatments. Indeed, treatment of CRPS may be described overall as generally ineffective. There is growing support for multidisciplinary approaches to CRPS treatment and certain promising new approaches. Nonpharmacological treatment in the form of physiotherapy and occupational therapy may be helpful. In particular, occupational therapy may help improve functionality and the ability of the patient to carry on everyday activities. Pharmacological treatment is individualized and may include steroids, free radical scavengers, neuropathic pain treatments, and drugs that interfere with bone metabolism such as calcitonin and bisphosphonates. [1]

Ketamine, an N-methyl-D-aspartate (NMDA) antagonist, has been evaluated in various acute and chronic pain syndromes, and has been reported to be of benefit in the treatment of refractory neuropathic conditions including CRPS.

Patients with CRPS experience intense pain but also significant functional disability and psychological distress. [2] In addition to antidepressants and anxiolytics, these patients often require cognitive behavioral and other psychological supportive services.

There are currently no medical tests for Complex Regional Pain Syndrome (CRPS), a clinical diagnosis being based entirely upon an accepted set of guidelines. At their conference in 2004, the International Association for the Study of Pain (IASP) adopted a new set of guidelines for diagnosing CRPS, superseding guidelines which had been in place for the previous decade. As the conference took place in Budapest, the new guidelines were named the Budapest Criteria.[3]

[1] Joseph V Pergolizzi, Jo Ann LeQuang, et al. The Budapest criteria for complex regional pain syndrome: The diagnostic challenge. Review Article – Anesthesiology and Clinical Science Research (2018) Volume 2, Issue 1.

[2] Rewhorn MJ, Leung A, et al. J Foot Ankle Surg. 2014 May-Jun; 53(3):256-8. Incidence of complex regional pain syndrome after foot and ankle surgery.

[3] Goebel A, Bisla J, Carganillo R, et al. A randomised placebo-controlled Phase III multicentre trial: low-dose intravenous immunoglobulin treatment for long-standing complex regional pain syndrome (LIPS trial). Southampton (UK): NIHR Journals Library; 2017 Nov. (Efficacy and Mechanism Evaluation, No. 4.5.) Appendix 3, Research diagnostic criteria (the ‘Budapest Criteria’) for complex regional pain syndrome. Available from:

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