I injured my left knee (sever medial meniscus, ACL, MCL). After the surgery in August 1977, I had given up my crutches after 4 days and was walking around on it, albeit gingerly. I played basketball in October/November 1977. I've had to put up with periodic pain (about 6 - 8 times a year, for a couple of days).
However, it was not until 30 years later that I completely bend the leg. It would not surprise me if the arthritis got in the way, as I had gave up my sports and turned into a couch potato,