Central Sensitization and Nociplastic Pain in Pes Planus

NCT07125781 | Completed

• 1 other identifier: 2024/30
• Study Type: observational
• Target: 214
• Locations: 1 country
• Sites: 1

Brief Summary

Background: Pes planus, commonly known as flatfoot, is a condition characterized by the collapse of the medial longitudinal arch of the foot. While some individuals remain asymptomatic, many experience foot or leg pain, walking difficulties, and functional limitations. In some cases, symptoms persist despite adequate conventional treatment. This suggests that central pain mechanisms, such as central sensitization and nociplastic pain, may contribute to ongoing symptoms. These mechanisms involve changes in the central nervous system that amplify pain perception and can occur even in the absence of active tissue damage. Understanding these mechanisms in pes planus may help guide more targeted and effective treatment strategies. Purpose: The aim of this multicenter cross-sectional study was to determine the prevalence of central sensitization and nociplastic pain in individuals with clinically diagnosed pes planus and to compare the findings with age- and sex-matched healthy controls. Methods: Between November 2024 and May 2025, a total of 107 patients with pes planus and 107 healthy controls were recruited from three medical centers. Participants completed validated Turkish versions of the Visual Analog Scale for pain intensity, the Foot Function Index for functional limitation, the Pain-DETECT questionnaire for nociplastic pain symptoms, the Central Sensitization Inventory for central sensitization, the Hospital Anxiety and Depression Scale for psychological distress, and the Short Form-12 for quality of life. Data were analyzed using comparative statistical tests and multiple linear regression models to identify factors associated with nociplastic pain and central sensitization in the pes planus group.

Conditions

Pes Planus; Flatfoot; Central Sensitization; Nociplastic Pain

Keywords

Pes Planus; Flatfoot; Central Sensitization Inventory; Nociplastic Pain; Pain-DETECT Questionnaire; Foot Function Index; Chronic Foot Pain; Biopsychosocial Pain Mechanisms

Outcome Measures

Primary Outcomes (2)

• Pain-DETECT questionnaire

  The Pain-DETECT questionnaire consists of 9 items with a total score range of 1-38. Scores ≤12 indicate that neuropathic or nociplastic pain components are unlikely, 13-18 indicate uncertainty, and ≥19 indicate probable nociplastic or neuropathic pain. The validated Turkish version, developed by Alkan et al. (2013), demonstrated a sensitivity of 90% and specificity of 67.5% for the ≤12 cutoff, with a negative predictive value of 87%.

  Baseline

• Central Sensitization Inventory

  The Central Sensitization Inventory contains 25 items scored 0-4 (0 = never, 4 = always). Total scores ≥40 indicate the presence of central sensitization, with severity categories as follows: 0-29 subclinical, 30-39 mild, 40-49 moderate, 50-59 severe, ≥60 very severe. The validated Turkish version, developed by Keleş et al. (2021), reported 81% sensitivity and 75% specificity for the ≥40 cutoff, with excellent internal consistency (Cronbach's alpha = 0.92) and test-retest reliability (intraclass correlation coefficient = 0.93).

  Baseline

Secondary Outcomes (4)

• Visual Analog Scale

  Baseline

• Foot Function Index

  Baseline

• Hospital Anxiety and Depression Scale

  Baseline

• Short Form-12 Health Survey (SF-12)

  Baseline

Study Arms (2)

the patient group

Adults aged 18 to 65 years with a clinical diagnosis of pes planus confirmed by a physical medicine and rehabilitation specialist, experiencing lower extremity pain for at least six months. Participants completed validated questionnaires to assess pain intensity, foot function, nociplastic pain features, central sensitization, psychological status, and quality of life. No therapeutic intervention was administered as part of the study.

The control group

Age- and sex-matched healthy volunteers with no current or past foot or leg pain. Participants had no history of pes planus, lower limb surgery, trauma, or rheumatologic, neurologic, endocrine, or vascular disorders that could influence pain perception. No interventions were applied; they completed the same validated questionnaires as the pes planus group for comparison purposes.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18-65 years, including individuals with clinically diagnosed pes planus and age- and sex-matched healthy volunteers without lower extremity pain. Participants were recruited from physical medicine and rehabilitation clinics at Etlik Zübeyde Hanım Gynecology and Pediatrics Training and Research Hospital, Ankara Etlik City Hospital, and Yozgat City Hospital.

You may qualify if:

• Age between 18 and 65 years.
• For pes planus group: clinically diagnosed pes planus confirmed by physical medicine and rehabilitation specialists, with persistent lower extremity pain for at least 6 months.
• For control group: age- and sex-matched healthy volunteers without current or past foot or leg pain.
• Willingness to complete all self-report questionnaires.
• Provided written and verbal informed consent.

You may not qualify if:

• History of diabetes mellitus, hypothyroidism, malignancy, vasculitis, neuropathies, or lumbar radiculopathy.
• History of lower limb surgery or trauma.
• Recent local injection or extracorporeal shockwave therapy.
• Any rheumatologic disease affecting pain perception (e.g., rheumatoid arthritis, ankylosing spondylitis).
• Severe psychiatric disorder or cognitive impairment interfering with questionnaire completion.

Sponsors & Collaborators

• Bozok University: lead

Study Sites (1)

Yozgat Bozok University Faculty of Medicine, Department of Physical Medicine and Rehabilitation

Yozgat, Yozgat, 66100, Turkey (Türkiye)

Location

Related Publications (2)

• Alkan H, Ardic F, Erdogan C, Sahin F, Sarsan A, Findikoglu G. Turkish version of the painDETECT questionnaire in the assessment of neuropathic pain: a validity and reliability study. Pain Med. 2013 Dec;14(12):1933-43. doi: 10.1111/pme.12222. Epub 2013 Aug 7.

  PMID: 23924395 BACKGROUND

• Buldys K, Gornicki T, Kalka D, Szuster E, Biernikiewicz M, Markuszewski L, Sobieszczanska M. What Do We Know about Nociplastic Pain? Healthcare (Basel). 2023 Jun 17;11(12):1794. doi: 10.3390/healthcare11121794.

  PMID: 37372912 BACKGROUND

MeSH Terms

Conditions

Flatfoot; Nociplastic Pain

Condition Hierarchy (Ancestors)

Talipes; Foot Deformities, Acquired; Foot Deformities; Musculoskeletal Diseases; Foot Deformities, Congenital; Lower Extremity Deformities, Congenital; Limb Deformities, Congenital; Musculoskeletal Abnormalities; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor, Principal Investigator

Study Record Dates

• First Submitted: August 10, 2025
• First Posted: August 15, 2025
• Study Start: November 27, 2024
• Primary Completion: May 31, 2025
• Study Completion: May 31, 2025
• Last Updated: August 15, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: De-identified individual participant data and supporting materials will be available beginning 6 months after publication of the main study results and will be accessible for a period of 12 months thereafter.
• Access Criteria: Data will be available to qualified researchers with a methodologically sound proposal for secondary analyses related to the study objectives. Requests should be submitted to the corresponding author at gulserendmr58@hotmail.com. Approved requestors will be provided access via secure email or institutional file transfer systems.

Locations

TU (1)