Study protocol: outcomes of REvision surgery after primary JOINt replacement (REJOIN) study : a prospective cohort study

The number of arthroplasty revision surgeries is increasing, yet patient-centred outcomes such as mental wellbeing, fulfilment of expectations for postoperative outcomes such as pain, function, and activities of daily living, as outlined in the Hospital for Special Surgery Knee Scale (HSS), and the Hip/Knee Replacement Expectations Survey (HRES/KRES), as well as the importance patients assign to such outcomes, remain insufficiently understood. Moreover, little is known about the role of their significant others. While essential to patients' recovery and wellbeing, they may experience substantial emotional and practical burdens themselves. Here we present the protocol of the REJOIN study (Outcomes of REvision surgery after primary JOINt replacement), which aims to examine the impact of revision surgery on patients and their significant others. The study describes patients' expectations and their fulfilment, mental wellbeing, functional outcomes, and the perceived value of outcomes following surgery, as well as the health-related quality of life (QoL) and caregiver burden experienced by their significant others. In addition, it investigates risk factors associated with the aforementioned outcomes.

This will be a multicentre, longitudinal observational study. All eligible patients scheduled for revision surgery after total hip or knee arthroplasty between March 2026 and February 2033 are invited to participate together with their significant other. We aim to include 3,650 patients. Data will be gathered preoperatively, and at three, six, 12, and 24 months.

The main outcome parameters are expectations and their fulfilment, measured through three different data sources: patient-reported outcome measures (PROMs) gathered for usual care, patients' medical files, and study questionnaires. The PROMs comprise of the HSS, HRES/KRES, mental health (Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Screen (HADS)), QoL (EuroQol five-dimension questionnaire (EQ-5D)), pain (Numeric Rating Scale (NRS) pain), hip/knee functioning (Oxford Hip Score/Oxford Knee Score (OHS/OKS)), patient-prioritized importance of outcomes (their top three), strain on significant other (CarerQol-7D), positive experiences of significant other (PES), and hip/knee function according to significant other (OHS/OKS by significant other).

The REJOIN study offers a systematic approach to evaluate the impact of revision surgery on patients and their significant others with regard to expectation fulfilment, mental wellbeing, and functional outcome.