Rehabilitation after primary knee or hip arthroplasty may include performing exercises with a physiotherapist. For patients who can work well with a computer, tablet or smartphone, it is now possible to use a mobile application (e.g. moveUp) to carry out a large part of the exercises more independently. This is done with online guidance by a physiotherapist via a mobile application that is CE marked in Europe.

This study will investigate whether the effect of the mobile application on knee or hip rehabilitation and quality of life is equal to that of standard care (i.e. without the use of a mobile application).

Via the moveUP Coach App, patients receive personalized rehabilitation for knee or hip replacement, both before and after surgery. This mobile application is on the market, meets the legal requirements in Europe and has been provisionally remunerated under an agreement (convention) between the mandatory health insurance (NIHDI) and the hospital that participate in this study.

Eligible patients will be randomized to one of the three treatment options of the study:

1. The "usual care group" will not be informed in detail about the mobile application and will receive usual rehabilitation care for knee- or hip replacement.
2. The group "possibility to use the mobile application with a predefined number of physiotherapy sessions" will receive all necessary information on the mobile application and can still decide whether or not to receive rehabilitation with online guidance by a physiotherapist via the mobile application. A predefined number of traditional physiotherapy sessions is combined with the use of the mobile app in this group.
3. The group "possibility to use the mobile application without a predetermined number of physiotherapy sessions" will receive all necessary information on the mobile application and can still decide whether or not to receive rehabilitation with online guidance by a physiotherapist via the mobile application. No predefined number of traditional physiotherapy sessions are required.

The patient will be asked to complete 2 questionnaires (KOOS-JR/HOOS-JR and EQ5D-5L) at baseline, 6 weeks and 6 months after arthroplasty. These patient reported outcomes will give an indication on the rehabilitation outcome and quality of life compared in the 3 groups.

At the end of the study, a health economic evaluation is foreseen by the Federal Knowledge Center for Healthcare (KCE). In this way the results can be helpful in getting a more definitive refund for the mobile application in Belgium.

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 physical therapist physically being present.
9. The patient is willing to complete online the patient reported outcomes and is aware that if he/she fails in this computer literacy test (performed before randomization) he/she will not be randomized and hence not included in the study. He/she will receive usual rehabilitation care.