INFECTION IN TKR. What shall we do.

My mother had under gone total knee replacement 4 years before, after 1 yr of knee replacement she suffered from  chikengunia after that slowly slowly knee replacement become less effective. 1 month before she fall down while trying to get up from bed for wash room. After that she is unable to do movement by herself. Doctor say this might be due to urine and bacterial infection and need to re operate knee for re plant knee. She is taking medicine of infection since 1 month, but still not fully recovered. At presently she has got redness on knee and knee temperature is slightly high from rest of body. Recently before 10 days her kidney was operated and removed due to 10 cm cancer tumer, she is recovering from that. Please advise what shall we do.