Background: Clinical decision-making in total knee arthroplasty (TKA) is a complex process needing further clarification. The aim of this study was to compare TKA eligibility criteria considered most important by orthopedic surgeons (OSs) to characteristics of patients with knee osteoarthritis (OA) eventually found eligible for TKA. Methods: Nine OSs chose the five criteria most important when deciding on TKA eligibility. Cross-sectional data from 200 patients found either eligible (n = 100) or not eligible (n = 100) for TKA by one of the nine OS, were analyzed in a regression analyses with TKA eligibility as the dependent variable. Results: Radiographic severity (n = 8), pain (n = 9), functional disability (n = 8) and not responding to the recommended non-surgical treatment (n = 7) were considered most important by OSs.Associations (P < 0.25) between TKA eligibility and criteria found important by the OS were demonstrated for worse radiographic severity and more functional limitations, but not for pain and not responding to the recommended non-surgical treatment.Furthermore, more comorbidities and higher Body Mass Index (BMI) were associated with TKA-eligibility, but not found important for TKA eligibility by the OS. Conclusion: Radiographic severity and functional limitations were confirmed as drivers for TKA eligibility, while pain was not. Not responding to non-surgical treatment was not included in the decision-making, suggesting low uptake of clinical guidelines in clinical practice. This study highlights the complexity of the decision-making with some overlap between the criteria that OSs think they apply and what is actually applied in clinical practice.