My Husband Is Taking Diclofenac 50 Mg Tid For Knee

My husband is taking diclofenac 50 mg tid for knee pain times 8 months, waiting on a knee replacement surgery. There is lots of swelling, makes its hard to walk around sometimes. Question, can he take ibuprofen 800 mg bid (over counter) in place of the diclofenac but not both together - the ibuprofen helps with the swelling more and therefore he walks better.