['The purpose 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 Knee Society Scores (KSS) after total knee arthroplasty (TKA).', 'Data from 99 patients collected during a randomized clinical trial were used for this secondary data analysis. The KSS scores of the patients were measured preoperatively and at 4-years follow-up. Multiple regression analyses were performed to investigate which combination of variables would be the best to predict the 4-years KSS scores.', 'When considering SMF alone the combination of four of them significantly predicted the 4-years KSS-F score (p\u2009=\u20090.009), explaining 18\xa0% of its variation. When considering only PSF the combination of age and body weight significantly predicted the 4-years KSS-F (p\u2009=\u20090.008), explaining 11\xa0% of its variation. When considering both groups of predictors simultaneously the combination of three PSF and two SMF significantly predicted the 4-years KSS-F (p\u2009=\u20090.007), explaining 20\xa0% of its variation.'] Do surgically modifiable factors measured by computer-navigation together with patient-specific factors predict knee society score after total knee arthroplasty?