INTRODUCTION. The Patient Activity Treatment Outcome Scale (PATOS) is a novel patient-reported outcome measure (PROM). This study explored patients’ and orthopaedic surgeons’ experiences with PATOS as part of a PROM battery. It aimed to investigate its influence on patient involvement and healthcare decisions about knee or hip osteoarthritis patients scheduled for knee/hip arthroplasty. METHODS. A qualitative research design was adopted using semi-structured interviews with 19 patients and nine orthopaedic surgeons at a Danish orthopaedic surgery department. Thematic analysis was used to develop key themes from interview transcripts. RESULTS. This study adds nuanced insights related to the use of PROMs in routine orthopaedic clinical practice. Home-based completion of PROMs prompted patients to reflect on their situations, priorities and goals regarding potential hip or knee arthroplasty, leading to better-prepared discussions with surgeons. The integration of PATOS with other PROMs made it challenging to discuss PATOS exclusively. Therefore, the results relate to the full PROM battery. The experiences of patients and surgeons were organised into four themes: 1) Patient involvement is key, 2) Questionnaire load, 3) Meaningful home-based completion and 4) PROMs were not used in the decision-making process. CONCLUSIONS. The questionnaire load and limited integration into healthcare decision processes raised concerns about the application of the PROM battery. The results emphasise the importance of refining the application of PROMs in orthopaedic practice from the perspectives of patients and surgeons alike. FUNDING. This work was supported by Innovation Fund Denmark [0172-01258B] TRIAL REGISTRATION. Not relevant.