Surgery Go Ahead

My brother had full knee replacement. Ever since he has had some problems. They said he had some infection around the incision so are giving him antibiotics for 10 days. He has been having physical therapy now for several days and was doing well. Or at least we thought so. This morning he called and said they were going to x-ray the knee as they felt something may be wrong inside. I sure hope not. I would hope they wouldn't have to open it up again. That would be horrific. His blood pressure is too low too so hope they figure that out.