Clinical outcomes of patients lost to follow-up and factors affecting follow-up loss after total knee arthroplasty

Background The hypotheses were as follows: 1) the clinical outcome of patients lost to follow-up after total knee arthroplasty (TKA) will be different compared to patients with follow-up; 2) follow-up rate will be affected by various social economic factors. Methods Patients who underwent TKA between March 2019 and February 2020 were retrospectively included. Patients lost to follow-up were defined as patients who did not undergo follow-up 6 months after TKA; all patients were divided into follow-up and follow-up loss groups. Western Ontario and McMaster Universities Osteoarthritis (WOMAC) and Knee Society Score (KSS) were measured before surgery. After surgery, WOMAC, KSS function, and satisfaction were measured via telephone. Age, sex, unilateral or bilateral TKA, distance from hospital, presence of a family, and insurance were investigated. Results A total of 137 patients were included in the study. There were 92 (67.2%) patients that followed up 6 months after TKA, on the other hand, 45 patients (32.8%) were lost to follow-up. There was no difference in clinical outcomes (WOMAC, p = 0.932; KSS clinical, p = 0.450) and satisfaction (pain: p = 0.230, function: p = 0.300) between two groups. Age, sex, unilateral or bilateral TKA, distance from hospital, presence of a family, and insurance had no effect on follow-up rates. Conclusion The clinical outcomes of patients lost to follow-up after TKA did not show a difference from those who were followed up. Age, sex, unilateral or bilateral TKA, distance from hospital, presence of a family, insurance status, and postoperative clinical symptoms did not affect the follow-up rate.