Patient Reported Outcome Measures (PROMs) in Rehabilitation With or Without the Possible Use of a Mobile Application After Primary Knee or Hip Arthroplasty

Eligibility criteria: 1. The patient is aged 18 years or older, has a Belgian National Number, is insured by a Belgian sickness fund, and is not staying in a nursing home or long term rehabilitation centre. 2. The patient has sufficient knowledge of Dutch, French, German or English. 3. The patient has a planned date between the next 1 to 8 weeks for a primary unilateral unicompartmental knee arthroplasty (UKA); a bicompartmental knee arthroplasty, (BKA), consisting of either two UKA or a UKA and a patellar replacement; or a total knee arthroplasty (TKA) or a total hip arthroplasty (THA). 4. The patient is not planned to have a peri-operative procedure (e.g. intra-articular catheter) or postoperative procedure that is expected to significantly impact the rehabilitation in and out of hospital. 5. In the 6 months after arthroplasty the patient is not planned to have surgery that may impact the arthroplasty rehabilitation. 6. The patient is not suffering from a medical condition (e.g. Parkinson, multiple sclerosis, cerebrovascular accident) that is expected to significantly impact the rehabilitation or that constitutes a contra-indication for the use of the mobile application. 7. The patient confirms to have easy and daily access to the internet, a mobile phone, a personal email address and a computer, tablet or smartphone, until 8 months after randomization. 8. The patient does not upfront exclude the possibility whereby part of the rehabilitation is performed without a physica…