[version 1; peer review: awaiting peer review]
No competing interests were disclosed.
Over the past decades, multiple classification systems have been used to describe a spectrum of painful adult-acquired flatfoot. Among the most widely used classifications and terminology are posterior tibial tendon dysfunction (PTTD), adult-acquired flatfoot deformity (AAFD), and progressive collapsing foot deformity (PCFD). Although classification systems have evolved considerably over time, participant selection criteria have not been standardized across studies. Consequently, substantial heterogeneity exists in how these conditions are defined and operationalized in the literature. This variability limits comparability across studies, contributes to inconsistencies in reported outcomes, and ultimately limits the advancement of this field.
The purpose of this scoping review will be to map and characterize the participant selection criteria used in research involving PTTD, AAFD, and PCFD, and to describe the extent of methodological variation across literature.
Eligible studies will include peer-reviewed qualitative, quantitative, and mixed-methods research involving adults diagnosed with PTTD, AAFD, or PCFD. Studies will be excluded if they include asymptomatic flatfoot.
A comprehensive search will be conducted in MEDLINE (PubMed), SPORTDiscus, CINAHL, Cochrane Library (CENTRAL), Physiotherapy Evidence Database (PEDro), Scopus, and Google Scholar. Two independent reviewers will perform study selection, with disagreements resolved by consensus or a third reviewer. Data will be extracted using a piloted standardized form and will include study characteristics, inclusion and exclusion criteria, and demographic variables. Findings will be synthesized using descriptive numerical summaries and narrative mapping.
By systematically mapping participant selection criteria and demographic characteristics across studies, this scoping review will explore the extent of methodological variability in the PTTD, AAFD, and PCFD literature. The findings will inform future efforts aimed at improving standardization of selection criteria, thereby enhancing methodological consistency and comparability across studies investigating this spectrum of painful adult-acquired flatfoot disorders.
Progressive collapsing foot deformity (PCFD),
Epidemiologically, PTTD/PCFD/AAFD primarily affects middle-aged and older adults, with an estimated prevalence of approximately 3.3% in women, an incidence nearly twice as high in women compared to men, and reported rates approaching 10% in individuals over 65 years of age.
In 2020, Myerson et al.
Therefore, the purpose of this scoping review will be to map and characterize the participant selection criteria used in research involving PTTD, AAFD, and PCFD, and to describe the extent of methodological variation across the literature. While this review focuses on participant selection criteria, these are interpreted as the operationalization of diagnostic criteria within research contexts.
Based on the PCC framework (Participants, Concept, Context), as recommended by Joanna Briggs Institute (JBI) for scoping reviews,
The secondary review questions are as follows:
How frequently are specific inclusion and exclusion criteria, diagnostic approaches, and classification systems used across the literature? How have the terminology, conceptualization, and diagnostic criteria applied to PTTD, AAFD, and PCFD within research, evolved over time? How do participant selection criteria vary by study design and clinical context (e.g., surgical vs non-surgical studies)? What demographic and clinical characteristics are most reported to describe study populations? What gaps or inconsistencies exist in the reporting and operationalisation of participant selection criteria?
These questions will guide the review in mapping and describing the available evidence regarding participant selection methodologies in studies involving individuals with PTTD, AAFD, and PCFD.
| Element (PCC) | Inclusion Criteria | Exclusion Criteria |
|---|---|---|
| Participants (Population) | Studies involving adult human participants defined with posterior tibial tendon dysfunction (PTTD), adult-acquired flatfoot deformity (AAFD), or progressive collapsing foot deformity (PCFD), as defined within the study.
Etiology (e.g., degenerative, rheumatologic, traumatic, inflammatory, overuse) Laterality (unilateral or bilateral) Sex, gender, ethnicity, or geographic location |
Studies involving asymptomatic flatfoot populations Studies involving non-human or cadaveric participants |
| Concept | Studies reporting explicit inclusion and/or exclusion criteria used to define participants with PTTD, AAFD, or PCFD.
Clinical signs and symptoms Imaging findings (Magnetic resonance imaging, ultrasound, radiographs) Functional assessments Structural or alignment measures Classification and staging systems |
Studies that do not report participant selection criteria Studies focused solely on clinical diagnoses in the absence of a clearly defined diagnosis criteria |
| Context | Studies conducted in any research setting, including:
Clinical environments Surgical settings Laboratory or biomechanical settings Rehabilitation or sports medicine settings Community-based settings |
No explicit exclusions based on context, provided the study involves research application of participant selection criteria. |
| Types of Evidence Sources |
Peer-reviewed quantitative, qualitative, and mixed-methods studies Studies that include defined participant recruitment criteria |
Case reports and case series Systematic reviews and meta-analyses Narrative reviews, editorials, and commentaries Conference abstracts and proceedings Study protocols Theses and dissertations |
| Other Limits |
Publications in English or French Studies published in 2006 or after |
The scoping review will be conducted in accordance with the methodological guidance provided by Arksey and O’Malley
The search strategy will aim to locate published peer-reviewed original studies, quantitative, qualitative, and mixed method studies (
The modified strategy applied in other databases is outlined in additional material.
| Scopus (Elsevier) | TITLE-ABS-KEY (PTTD OR “acquired flatfoot” OR AAFD OR “progressive collapsing foot deformity” OR PCFD OR “tibialis posterior dysfunction” OR “tibialis posterior insufficiency” OR ((“posterior tibial” OR “tibialis posterior”) W/5 (dysfunction OR insufficiency OR tendinopathy OR tendinitis))) |
Electronic databases to be searched will include Scopus, SPORTDiscus (EBSCO), CINAHL (EBSCO), MEDLINE (EBSCO), Cochrane Library (CENTRAL) and Physiotherapy Evidence Database (PEDro). Additionally, grey literature will be explored using Google Scholar.
Following the search, all identified records will be collated and uploaded into EndNote software version 21.5 (Clarivate Analytics, PA, USA) and duplicates will be removed. Following a pilot test, titles and abstracts will be screened using Rayyan (Rayyan Systems Inc., Qatar), by two independent reviewers (LT and AD) for assessment against the inclusion criteria for the review. Potentially relevant papers will be retrieved in full text and will be assessed in detail against the inclusion criteria by two independent reviewers (LT and AD). Reasons for exclusion of full-text papers that do not meet the inclusion criteria will be recorded and reported in the scoping review. Any disagreements that arise between the reviewers at each stage of the selection process will be resolved through discussion or with a third reviewer (GM). The search results and exclusion rationale will be reported in full in the final scoping review and presented in a PRISMA flow diagram.
Data will be extracted from included publications by one reviewer (AJ) using a data extraction tool developed by the research team. Data will be imported into a table created in a Microsoft Excel version 16.79.1 (Microsoft Corporation, WA, USA) sheet (supp
Study characteristics (journal, authors, year, journal, country where the study was conducted, study design, sample size). Inclusion criteria Exclusion criteria Demographic variables
A draft extraction tool is provided and will be modified and revised as necessary during the process of extracting data from each included paper. Modifications will be detailed in the full scoping review. Authors of papers will be contacted to request missing or additional data, where required. If the corresponding author does not respond, the article will still be included, but problematic results will not be analyzed, and limitations will be mentioned in the discussion.
The results of the review will be analyzed and displayed in tabular format using charting methods to meet the objectives of this scoping review. The results will be presented in a narrative format. Consistent with scoping review methodology, a formal assessment of methodological quality or risk of bias will not be undertaken, and this will be explicitly acknowledged in the review.
As this scoping review involves the synthesis and analysis of data from previously published literature, ethical approval is not required. Nevertheless, all included sources will be appropriately referenced. The findings of this review will be disseminated through peer-reviewed publications and presentations at scientific conferences. The review methodology will be conducted and reported in accordance with the PRISMA-ScR guidelines
The search strategy, including the development of keywords and Medical Subject Headings (MeSH) adapted to each database, has been completed. Literature searching and article screening will begin following peer review of the search strategy.
Despite a large body of literature on painful adult-acquired flatfoot disorders, there is still no clear consistency in how these conditions are defined in research. Participant selection criteria vary widely between studies and are often incompletely reported, which limits comparability and makes it difficult to synthesize findings across the literature. In many cases, diagnostic labels are applied without a clear description of the clinical, imaging, or functional criteria used to define study participants. This limits clarity regarding how the results are interpreted and applied across different study designs and clinical contexts.
This scoping review will map and characterize the inclusion and exclusion criteria used in research to define individuals with PTTD, AAFD, and PCFD. The review will also provide a structured overview of how these conditions are defined in practice and how this has evolved over time. It will also describe how these criteria vary across study designs and clinical settings. Overall, this synthesis will help clarify current inconsistencies and highlight areas where standardization is lacking. This will ultimately support the development of more consistent research practices, improving comparability across studies in this disabling musculoskeletal disorder.
No data is associated with this article.
Open Science Framework: “Selection criteria in posterior tibialis tendon dysfunction, adult acquired flatfoot and progressive collapsing foot deformity research: a scoping review protocol (
Open Science Framework: PRISMA-ScR protocol checklist
Data are available under the terms of the
N.A.