Data collection
’ personality dimensions
Patients were followed for 12 months post-operatively during the regular administrative procedures of the participating hospitals. Evaluation started in 05/2018 and ended in 01/2021. Baseline data (age, age at surgery, sex, type of surgery, ASA score, BMI, marital status, education level and income) for the eligible patients were elicited before surgery. Patients’ personality dimensions were queried pre-operatively using the German version of the revised Life Orientation Test (LOT-R) (Fig. Revised Life Orientation Test (LOT-R)The surveys (LOT-R, KOOS-12) were handed to included patients after informed consent during the last visit at the outpatient clinic prior to surgery (range 1–8 weeks), and post-operative at the above-described follow-ups. Patients completed the surveys on their own, with qualified study nurses on-site on demand if questions arose. Collected data was pseudonymized and stored electronically.