Patella femoral pain syndrome is just the term that describes pain in the area behind and around the patella. That can have many reasons. One of them can be retropatellar arthrosis (arthritis on the back of the knee cap).
The term “runner’s knee” usually describes pain on the lateral part of the knee. That’s the insertion point of the iliotibial band. That’s why it is also called Iliotibial Band Syndrome – ITB Syndrome. Although it’s not that clear what really causes the pain.
Radiological signs of arthritis can be, but must not be a cause of pain.
So where exactly is your pain? I assume that someone examined your knee?! MD or physio!? What did they tell you?
And one more question: Why did you get hip surgery and what was done? Was it the same side that is bothering you now?
Sorry for more questions than answers. But I hope that I can really help you when we have figured that out;-)