['There are multiple factors affecting maximal knee flexion (MKF) after total knee arthroplasty (TKA). The aim of the study was to investigate whether patient-specific factors (PSF) and surgically modifiable factors (SMF), measured by means of a computer-assisted navigation system, can predict the MKF after TKA.', 'Data from 99 patients collected during a randomized clinical trial were used for this secondary data analysis. The MKF of the patients was measured preoperatively and 1-year post-surgery. Multiple regression analyses were performed to investigate which combination of variables would be the best to predict the 1-year MKF.', 'When considering SMF alone, the combination of three factors significantly predicted the 1-year MKF (p\xa0=\xa00.001), explaining 22\xa0% of its variation. When considering only PSF, the combination of pre-op MKF and BMI significantly predicted the 1-year MKF (p\xa0<\xa00.001), explaining 23\xa0% of its variation. When considering both groups of potential predictors simultaneously, the combination of five SMF with two PSF significantly predicted the 1-year MKF (p\xa0=\xa00.001), explaining 32\xa0% of its variation.'] Do patient-specific and intra-operatively modifiable factors assessed by computer navigation predict maximal knee flexion one year after TKA?