Better Involved (Beter Betrokken)

INTERVENTION: usage of interactive app for smartphone and tablet with daily push notifications with information about a certain part of the discharge process (pain management, physio therapy exercises, home care, etc) CONDITION: Knee arthroplasty, Total knee arthroplasty, Osteoarthritis ; ; PRIMARY OUTCOME: ‐ increased self management SECONDARY OUTCOME: ‐ increased satisfaction ; ; ‐ increased sense of involvement from the hospital ; ; ‐ decrease in number of contacts with the hospitals INCLUSION CRITERIA: primary knee replacement > 40 years of age