You can’t diagnose arthritis (or conjunctivitis Or peritonitis or any other swollen, inflamed organ or tissue) from a picture, arthritis simply means inflamed joint. It can be infectious, degenerative, autoimmune, nutritional, genetic, traumatic or a combination. It most certainly isn’t any disease of the femoral head as that would apply only to the hip joint, the pictures are the head of the tibia/base of the femur. Most chronically swollen joints look the same, your knees or eyes or whatever only have a certain way of responding to chronic inflammation. Sending tissue into a pathologist might get an answer but a year after onset you may only get a diagnosis of chronic inflammation of unknown cause, and there certainly isn’t a way to treat joints that far gone. Initially you could treat a joint infection or immune mediated arthritis but once they look like that, it really doesn’t matter what the cause is. It is pretty easy to find a picture or video of similar neurological signs or swollen joints because the body has limited ways of reacting to issues in each particular system no matter the cause, just like car crashes mostly look the same whether you are drunk, texting, or putting on eye shadow at the time.