Prevalence of Neuropathic Pain Symptoms in Foot and Ankle Patients.

BACKGROUND

The management of pain in patients with foot and ankle pathology can be challenging. Cumulative data suggest that, in addition to nociceptive mechanisms, other neuropathic mechanisms can contribute to pain in a subset of people with orthopedic conditions, and can be found in 10.5% to 53% of patients with chronic pain, depending on the location of the pathology. Preoperative diagnosis of neuropathic pain (NP) can potentially change decision making and management of foot and ankle pathologies.

METHODS

We used a validated patient-reported pain questionnaire (painDETECT) as a cross-sectional study to investigate the prevalence of NP symptoms in a population of patients undergoing foot and ankle surgery. A total of 533 patients were prospectively included and completed the painDETECT questionnaire.

RESULTS

Sixty-six patients (12.4%) were classified as having a component of NP symptoms according to their painDETECT score. Current smokers (23.2%) had a significantly higher rate of developing NP symptoms than current nonsmokers (11.1%) ( P = .016). The location of the pathology and obesity had a moderate effect on the prevalence of NP symptoms. Patients with ankle-level pathology, excluding tarsal tunnel syndrome, had a marginally increased risk of having NP symptoms (15.4%) compared to patients with forefoot pathologies, excluding Morton's neuroma (7.5%, P = 0.06). Obesity also had a moderate effect on the NP risk, with 15.6% risk of NP symptoms for patients with BMI of 30 or more compared to 10% risk for patients with a BMI of less than 30 ( P = .06). Patients with NP symptoms reported significantly higher levels of current pain (7.2 vs 4.6, P < .001).

CONCLUSION

A considerable number of patients with foot and ankle problems requiring surgery had a neuropathic component of pain. Evaluation of their risk factors and level of pain may help with the diagnosis, decision making, and pain control. Further research is needed to evaluate the effect of preoperative NP on the short- and long-term results of surgeries.

LEVEL OF EVIDENCE

Level II, prospective cohort survey study.