First off, everyone recovery is different. You should not compare your knee surgery to my late wife's.
There was probably a decade between the two knee surgeries. Her initial recovery was great. She did everything asked of her. Over the long term, she suffered from knee pain. But than her problem wasn't caused by a sports injury it was osteoarthritis. By time she passed, the arthritis in her hands was so bad that we both worn the same size wedding ring in order to get it over her knuckle. My ring size for that finger is a 13. It's never changed.
I never got that way of thinking. "We're all different." "Don't compare yourself to anybody else."
Why?
Sure we are all different in a specific sense but biologically we are identical that live and function in an exact manner using the exact physiological principles. If not, a field such as medical science would not exist. Sure our heart rate may be different, your lung capacity and oxygen transfer different, how you respond to exercise, nutrition, medication, all vary; but the basic principles apply exactly to everyone. Antibiotics are used to treat a bacterial infection for everyone. I happen to be allergic to Penicillin, so I use Tetracycline. The specifics vary, the type of antibiotic, but the general principle is the same, using an antibiotic.
It makes perfect and logical sense to compare yourself to others on how you progress or regress in everything. It gives valuable information on the present condition. If performing a procedure on a 1,000 people that takes a mean average of six weeks to recover from but you are going on two months with little progress that should be an indication that something is wrong. If you recover in three weeks instead of six that would be an incentive to see if you did anything or if there was anything about you to aid recovery. Your diet, any supplements, exercise protocol.