## 2 Materials and Methods
### Detailed Presentations of the Methodological Steps of the DYNAMIKOS Model
#### 2.1.1 Development of the Casual Loop Diagram via Group Modeling Building Methodology (Phase A)
\begin{table}
\begin{tabular}{c c} \hline \hline
**Scripts** & **Purpose** \\ \hline \multirow{3}{*}{Hopes and Fears} & To elicit and establish group prospects for the GMB sessions and the DYNAMIKOS model development (performed at the start of the co-creation workshops). \\ \cline{2-3}  & To facilitate consensus-based DYNAMIKOS model \\ \cline{2-3}  & development and the potential variables that should be included (used early in the modeling process). \\ \hline \multirow{3}{*}{Causal mapping with seed structure} & To elicit causal structures of factors affecting KOA at the beginning of a GMB process, illustrating how the DYNAMIKOS model could involve a system of interacting feedback loops. \\ \cline{2-3}  & Intiating and Elaborating a “Causal Loop Diagram” or “Stock and Flow” model & To obtain an initial idea of KOA concepts and their factors relationships and initiate a Stock and Flow diagram. \\ \hline \multirow{3}{*}{Model Review} & To summarize the model structure and elicit feedback from stakeholders after causal structures for the risk factors of KOA have been developed. Typically, this script is used at the end of a session. \\ \cline{2-3}  & To identify the next steps needed and close the GMB session. \\ \cline{2-3}  & Modeling project community presentation & Present the DYNAMIKOS model to the community, with the aim to elicit feedback and build confidence about the DYNAMIKOS model. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main scripts used in the Group Modeling Building process for the DYNAMIKOS model. Adapted from [26]. 1.2 Collecting Real Data and Examining the Interrelationships That Affect the Development of KOA (Phase B)  
In this phase, based on the CLD results of the previous step, a questionnaire survey will be conducted to collect real data about the main risk factors affecting KOA and their complex interrelationships will be examined. Retrospective data will be collected using a questionnaire. The primary purpose of this part is to collect multiple historical data that describe the patient profile regarding the different aspects of the patient's life that affect KOA. The KOA questionnaire will be based on the results of Phase A (literature review and GMB workshops with stakeholders) and will explore the main risk factors affecting KOA. The questionnaire will be formulated using the specific methodology proposed in the literature [28; 29]. This questionnaire survey will collect historical data such as patients' socio-demographic characteristics (education and literacy, income, access to health services), details about previous injuries (e.g., previous knee injuries, details about the rehabilitation of injuries), possible other health conditions (e.g., diabetes mellitus), previous lifestyle, occupational activities, work (employment status), physical activity level, sports participation, ecological data (physical environment, climate), etc. In addition, age, weight, height, BMI, and sex will be recorded. Finally, the current patient reported knee function will be recorded using the Knee Injury and Osteoarthritis Outcome Score (KOOS) [30]. These data will be collected from patients diagnosed with KOA who have not been subjected to TKA. The primary data sources will be the University Hospitals' and private orthopaedic surgeons' databases via a certified approach by the primary researchers to identify patients with KOA. Subsequently, the relevant patient data from the databases will be extracted for further analysis. In continuum, patients diagnosed with KOA compiled by the databases will be approached personally by the investigators to collect additional retrospective data regarding details about their lifestyle that may lead to KOA. This information will be collected through interviews conducted with the patients and by completing the specific questionnaire (KOA questionnaire) that will be developed (Phase 2.2). We intend to enroll 500 participants in this survey. From this sample, 250 participants will represent patients diagnosed with KOA, and 250 will represent the matched control group.