Is it the surgeon, the patient, or the device? A comprehensive clinical and radiological evaluation of factors influencing patient satisfaction in 648 total knee arthroplasties

Total knee arthroplasty (TKA) is a successful and safe surgical procedure for treating osteoarthritic knees, but despite the overall good results, some patients remain dissatisfied. The aim of this study is to evaluate the influence of patient-related and surgery-related variables in a consecutive group of patients that underwent TKA. Individuals (n = 648) who had TKA performed between 01 January 2013 and 31 December 2017 were enrolled in the study. Postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Injury and Osteoarthritis Outcome Score (KOOS) and Forgotten Joint score (FJS-12) were collected at a mean follow-up of 4.79 years. Patient satisfaction was assessed with a questionnaire. Determinants of satisfaction (age, sex, smoking, presence of diabetes or cardiovascular disease, pain in other joints, preoperative arthritic stage) and components of satisfaction (slope variation, mechanical axis variation, outlier final alignment, surgeon experience) were examined to identify which variables correlated with positive outcome. Correlations with septic and mechanicals failures were also evaluated. Thirteen percent of patients were unsatisfied, despite good results in KOOS, WOMAC and FJS-12 tests. Female gender, low Kellgren–Lawrence grade and the presence of back pain and pain in other joints were factors associated with poor clinical results. Poorer clinical results were also reported in younger patients. Infection rate was correlated with active smoking and mechanical failure with an outlier final alignment. Comorbidities, smoking habits and high expectations have a big influence on TKA results and on final satisfaction after surgery.