@RedRider
When I saw my OS a month after my left knee blew up (summer 2013), he said almost every orthodoc has a story to tell about Levaquin (and, I suppose Cirpro and other fluoroquinolones). He said their effects were poorly understood, but appeared to have significant negative effects on connective tissues for some patients. My PT (doctorate) is young and had only been in practice about four years when I saw him. He told me he already had experiences with four or five cases of patients recovering from Achilles tendon ruptures while on Levaquin.
An old recap: At 5 weeks out from my LTKR I had very little swelling, flexion of near 120, was walking very normally, and doing moderate gym work including the elliptical up 40+ mts. A medical issue separate from my LTKR arose and I was put on Levaquin (I took it for 8-9 days). My sister, a veteran and now retired nurse, warned me of the RX at the outset. I felt miserable while on it. And, I was careful while on the Rx not to overdo (which I didn't feel like doing anyway). By the time I stopped with a couple of 24 hour doses left, I was moving like a 110 year old. Everything from my waist below including both legs was tight and painful.
The second day off of this Rx found me feeling much better and a couple days later I felt fine. I began to hit the gym again and did fine for a few days. I even increased my flexion a little. Then, and it was more than a week off the Rx, I had pain in the lateral side of my left knee about 55mts. into an elliptical session. I finished the 60 mts., but it hurt somewhat the next few days. I took four (4) days off from exercise, but it was the beginning of summer vacation and I wanted to get out and enjoy the sun and air. I did a just short of 2 hour spin on my bike on the flats. I was tight with some pain early, but it got better and I had no real discomfort (a little at times) until afterwards. Once I stopped, I realized it wasn't a good idea. I took a pain pill, iced, and napped. Within the following days, the knee got worse. More pain, tightness, and swelling. I was an idiot!
I have no way of knowing exactly what the effects of the Levaquin actually were, but I really think if I had just overdone things for a day then I would have recovered in a week or so then would be back on a normal track. Instead it took me most of the summer to get back near where I was 5+ weeks out. My flexion, despite PT and proper rest and exercise, did not return to where it was at 5 weeks (although it's better now as I noted in your thread). I think the Rx had an effect on my connective tissues that lingered, had a serious negative effect on my soft tissues leading to the blow up, and limited the healing processes of the tissues leaving me with a lot of work to do to regain extension (which I did) and a lot less flexion than I would otherwise have (based on pre-surgery and early recover, I think I would have had 135-140). The good long term news is that I can do anything I want with the knee (cycle, hike, even run a bit uphill).
This post was so long that I'll leave my Bob Marshall Wilderness story for later.
United States
And very exhausting. Your legs and knees must be in great shape to do all of that snowshoeing. 
