This qualitative systematic review protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) 2015 guidelines ensuring transparent reporting of planned methods (15). The protocol will be registered with the International Prospective Register of Systematic Reviews (PROSPERO) before commencing searches to promote transparency and reduce duplication. The review will employ the Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) statement for reporting qualitative synthesis and the Joanna Briggs Institute methodology for systematic reviews of qualitative evidence (16, 17). Any protocol amendments will be documented with dates, descriptions, and rationales. The review team includes expertise in osteoarthritis management, qualitative research methods, implementation science, and systematic review methodology, ensuring appropriate perspectives for comprehensive synthesis.

The review team comprises three members. RS will lead the search strategy, screening, data extraction, and synthesis. VS will serve as the second independent reviewer for title/abstract and full-text screening, data extraction, and quality appraisal. MRT will provide clinical expertise in osteoarthritis management, act as the third reviewer for resolving disagreements, and oversee methodological decisions throughout the review process.

The PICo framework (Population, phenomenon of Interest, Context) structures this systematic review, providing appropriate organization for qualitative evidence synthesis (18). The Population encompasses adults with knee osteoarthritis of any severity, duration, or etiology, including those with isolated knee osteoarthritis and those with multi-joint involvement where knee-specific data can be extracted. Healthcare providers involved in knee osteoarthritis management including general practitioners, rheumatologists, orthopedic surgeons, physiotherapists, occupational therapists, nurses, and other relevant professionals are also included. Family members, caregivers, and other stakeholders are eligible when their perspectives relate to patient uptake of interventions.

The phenomenon of Interest captures barriers and facilitators to uptake of guideline-recommended non-surgical interventions for knee osteoarthritis. This includes factors influencing initial engagement, ongoing participation, and sustained adherence to interventions. Core interventions of interest comprise exercise in any format including land-based, aquatic, supervised, or home programs; weight management encompassing dietary modification, physical activity for weight loss, and behavioral interventions; and education about osteoarthritis, self-management, and lifestyle modification. Adjunct interventions such as manual therapy, assistive devices, and complementary therapies are included when examined alongside core treatments. The review focuses on factors influencing real-world implementation rather than efficacy under controlled conditions.

The context component acknowledges that intervention uptake occurs within complex healthcare and social environments. All healthcare settings are eligible including primary care, specialist clinics, hospitals, community facilities, and home-based care. Studies from all countries and healthcare systems are included without language restrictions, recognizing that cultural, economic, and organizational factors profoundly influence intervention implementation. The temporal context spans from initial diagnosis through ongoing management, acknowledging that barriers and facilitators may evolve across the osteoarthritis trajectory.

While no single theoretical framework is imposed a priori on the synthesis, findings may be mapped post hoc to established implementation science frameworks such as the Theoretical Domains Framework (TDF) or the Capability, Opportunity, Motivation–Behavior (COM-B) model (19, 20). This approach preserves the inductive nature of thematic synthesis while enabling structured interpretation that can inform theory-driven implementation strategies.

Population criteria include adults aged 18 years and older with knee osteoarthritis diagnosed through clinical criteria, radiographic evidence, or self-report consistent with osteoarthritis symptoms. Studies including mixed arthritis populations are eligible if knee osteoarthritis data can be extracted separately. Healthcare providers of any profession involved in delivering non-surgical interventions for knee osteoarthritis are included regardless of experience level or practice setting. Studies examining perspectives of family members, informal caregivers, or healthcare administrators are eligible when focused on factors influencing patient intervention uptake.

The phenomenon of interest encompasses experiences, perceptions, attitudes, and beliefs about barriers and facilitators to engaging with non-surgical interventions for knee osteoarthritis. Studies must explicitly examine factors influencing intervention uptake, adoption, participation, or adherence rather than solely examining intervention effectiveness or satisfaction. Research exploring decision-making processes, motivation, behavior change, and implementation experiences are included. Studies focused exclusively on surgical interventions, pharmacological treatments without non-surgical components, or diagnostic procedures are excluded.

Study design criteria require qualitative methodology providing rich descriptive data about barriers and facilitators. Eligible designs include phenomenology exploring lived experiences of intervention engagement, grounded theory developing theoretical understanding of uptake processes, ethnography examining cultural influences on intervention participation, descriptive qualitative studies identifying barriers and facilitators, and action research documenting implementation experiences. Mixed-methods studies are eligible if qualitative components can be extracted and meet inclusion criteria. For mixed-methods studies, the qualitative component will be identified based on the presence of distinct qualitative data collection methods (e.g., interviews, focus groups, open-ended survey responses) and qualitative analytical approaches (e.g., thematic analysis, content analysis, grounded theory). Quality appraisal using CASP will focus solely on the qualitative component of such studies, assessing the rigour of qualitative data collection, analysis, and reporting independently of the quantitative elements. Studies in which qualitative findings are limited to brief open-ended responses without systematic qualitative analysis, or where qualitative data serve only as supplementary illustration of quantitative findings without independent qualitative inquiry, will be excluded. Purely quantitative studies, intervention effectiveness trials without qualitative process evaluation, and opinion pieces without empirical data are excluded (Table 1).

Comprehensive database searching will encompass seven major databases covering health, psychology, and rehabilitation literature. MEDLINE via PubMed will capture biomedical literature including clinical and health services research. Embase will provide international coverage including European and Asian studies often not indexed elsewhere. CINAHL will identify nursing and allied health perspectives crucial for understanding multidisciplinary intervention delivery. PsycINFO will capture psychological and behavioral aspects of intervention engagement. AMED (Allied and Complementary Medicine Database) will include rehabilitation and complementary therapy perspectives. Scopus and Web of Science will provide broad interdisciplinary coverage and enable citation tracking.

The search strategy combines four concept blocks refined through consultation with an information specialist experienced in qualitative systematic reviews. Knee osteoarthritis terms include “knee osteoarthritis,” “knee osteoarthrosis,” “knee arthritis,” “knee degeneration,” and “gonarthrosis.” Non-surgical intervention terms encompass “exercise,” “physical activity,” “weight management,” “diet,” “education,” “self-management,” “conservative treatment,” and “non-pharmacological.” Barriers and facilitators terms include “barriers,” “facilitators,” “enablers,” “obstacles,” “challenges,” “uptake,” “adherence,” “compliance,” “implementation,” and “engagement.” Qualitative research terms comprise “qualitative,” “interview,” “focus group,” “ethnography,” “phenomenology,” “grounded theory,” “thematic analysis,” and “content analysis.” The strategy accommodates terminology variations across disciplines and publication periods while maintaining sensitivity for qualitative research identification. The initial database searches are planned for March 2026, with an updated search to be conducted immediately prior to final analysis to capture any newly published studies. The date of each search will be recorded and reported in accordance with PRISMA-P guidance.

Supplementary search strategies will identify additional relevant studies through multiple approaches. Reference lists of included studies and relevant systematic reviews will be hand-searched. Forward citation searching using Google Scholar and Web of Science will identify studies citing key papers. Gray literature searching will include ProQuest Dissertations and Theses Global, conference proceedings from osteoarthritis and rehabilitation conferences, and websites of arthritis organizations and research centers. Content experts in osteoarthritis management and qualitative research will be contacted to identify unpublished or in-press studies. Authors of conference abstracts will be contacted for full study details where available.

Covidence systematic review software will manage the screening process, providing systematic tracking of decisions and reviewer agreement (21). Two reviewers will independently screen titles and abstracts against basic eligibility criteria, followed by full-text assessment of potentially eligible studies. Before commencing screening, reviewers will complete calibration exercises using 50 randomly selected citations to ensure consistent application of criteria. Inter-rater reliability will be calculated using Cohen’s kappa statistics with values above 0.75 indicating acceptable agreement.

The screening process involves initial assessment of titles and abstracts for basic eligibility focusing on population, phenomenon, and study design. Studies marked as potentially eligible by either reviewer proceed to full-text assessment. Full-text screening examines all eligibility criteria with specific reasons for exclusion documented. Disagreements between reviewers are resolved through discussion, with a third reviewer consulted when consensus cannot be reached. Authors are contacted when additional information is needed to determine eligibility, with three contact attempts over 4 weeks before exclusion. The PRISMA flow diagram will document study flow through screening stages including reasons for full-text exclusions.

A comprehensive data extraction form developed specifically for qualitative evidence will capture study characteristics, methodological details, and findings relevant to barriers and facilitators. The form was developed based on JBI guidance for qualitative data extraction and piloted on five studies to ensure completeness and usability. Two reviewers will independently extract data from each included study with discrepancies resolved through discussion and return to original sources. Authors will be contacted to clarify unclear information or obtain additional details about methods or findings.

Study characteristics extracted include author information, publication year, country and setting, funding sources, and declared conflicts of interest. Population characteristics encompass sample size and composition, participant demographics including age, gender, disease duration and severity, recruitment methods and settings, and inclusion and exclusion criteria. For healthcare provider participants, professional backgrounds, experience levels, and practice settings will be recorded. Methodological details include qualitative approach and theoretical framework, data collection methods and procedures, data analysis techniques, strategies for ensuring rigor and trustworthiness, and reflexivity statements about researcher positioning.

Intervention characteristics will document which non-surgical interventions were examined, how interventions were delivered in local contexts, and any implementation strategies employed. Findings extraction will focus on identified barriers organized by levels such as patient, provider, and system factors; identified facilitators similarly organized; participant quotations illustrating key barriers and facilitators; authors’ interpretations and theoretical developments; and any proposed strategies for improving uptake. Contextual information about healthcare system characteristics, cultural factors, and local implementation conditions will be extracted to enable assessment of finding transferability.

The Critical Appraisal Skills Program (CASP) Qualitative Research Checklist will assess methodological quality of included studies (22). This tool examines 10 key areas including clarity of research aims, appropriateness of qualitative methodology, research design suitability for addressing aims, recruitment strategy appropriateness, data collection methods addressing research issues, consideration of researcher-participant relationships, ethical considerations, rigor of data analysis, clarity of findings presentation, and research value. Two reviewers will independently assess each study with disagreements resolved through discussion.

Quality assessment will inform confidence in individual study contributions to synthesis findings rather than determining study exclusion. This approach recognizes that even studies with methodological limitations may provide valuable insights about barriers and facilitators. Studies will be categorized as high quality when meeting 8–10 CASP criteria, moderate quality when meeting five to seven criteria, or low quality when meeting fewer than five criteria. Gray literature sources, including dissertations, theses, and conference proceedings with sufficient methodological detail, will be appraised using the same CASP checklist applied to published studies. Where gray literature sources lack complete reporting of methodological procedures, this will be reflected in lower CASP ratings. In CERQual assessments, gray literature will not be weighted differently from published studies per se; however, methodological limitations identified through CASP appraisal will be factored into the methodological limitations component of CERQual, and any concerns about the adequacy or transparency of reporting will be documented. This approach ensures that gray literature can contribute valuable insights while maintaining rigorous quality standards. Sensitivity analyses will examine whether synthesis findings differ when lower quality studies are excluded. Temporal trends in study quality will be examined to understand methodological evolution in this field.

Thematic synthesis following Thomas and Harden’s three-stage approach will integrate findings across studies while preserving interpretive richness (23). This method was selected for its systematic approach to identifying patterns across studies while enabling development of new interpretive insights beyond individual study findings. NVivo qualitative analysis software will facilitate coding and theme development while maintaining an audit trail of analytical decisions.

The first stage involves line-by-line coding of study findings sections including participant quotations and author interpretations. Initial codes will remain close to the original data using participants’ own words where possible. Two reviewers will independently code five studies, comparing coding to develop a preliminary framework that will be refined throughout the synthesis. The second stage organizes codes into descriptive themes capturing patterns across studies. Descriptive themes will be developed separately for barriers and facilitators, with attention to different stakeholder perspectives and intervention types.

Barriers and facilitators related to adjunct interventions will not be synthesized as standalone themes. Rather, where studies report findings on adjunct interventions alongside core treatments, these data will be integrated into the synthesis only to the extent that they illuminate factors influencing uptake of core interventions (exercise, weight management, and education). Findings pertaining exclusively to adjunct interventions without relevance to core intervention uptake will be treated as contextual information and reported descriptively rather than incorporated into the thematic synthesis.

Constant comparison will identify similarities and differences across contexts and populations. The third stage develops analytical themes that go beyond individual study findings to generate new interpretive insights about factors influencing intervention uptake. These analytical themes will explore relationships between barriers and facilitators, mechanisms through which factors operate, and conditions under which factors become more or less influential.

Subgroup analyses will explore whether barriers and facilitators differ across key dimensions. Intervention-specific analyses will compare factors influencing exercise uptake versus weight management versus education, identifying common and unique challenges. Stakeholder comparisons will examine alignment and divergence between patient and provider perspectives. Contextual analyses will explore how healthcare system types, cultural backgrounds, and socioeconomic factors shape barriers and facilitators. Disease-related analyses will examine whether factors differ based on osteoarthritis severity, duration, or presence of comorbidities. These analyses will identify whether certain barriers and facilitators are universal versus context-specific.

The Confidence in Evidence from Reviews of Qualitative research (CERQual) approach will assess confidence in synthesized findings (24). This framework evaluates four components that may affect confidence in qualitative synthesis findings. Methodological limitations assess the extent to which studies contributing to a finding have methodological problems based on CASP assessments. Coherence evaluates whether findings are well-grounded in data from contributing studies and provide convincing explanations. Adequacy of data examines whether studies provide sufficiently rich data and whether enough studies contribute to develop understanding. Relevance assesses the extent to which contributing studies are applicable to the review question’s context, population, and phenomenon.

Each synthesized finding will receive an overall CERQual confidence rating of high, moderate, low, or very low based on assessment across all four components. Two reviewers will independently conduct CERQual assessments with disagreements resolved through discussion. Summary of Qualitative Findings tables will present each finding with its confidence assessment and explanation of the judgment. This transparent presentation enables users to understand the strength of evidence supporting each finding and make informed decisions about applicability to their contexts.