I teach at the college level and run a research lab, so this is not an ideal time to take off (hell, it never is, but during the semester is the least ideal) but I've got an aggressive but non-malignant mass that's eaten the top third to half of my fibula (which means I'm going to need my LCL and at least one hamstring tendon moved to attache to the tibia - now they're hanging loose), so it needs to come out ASAP. Hopefully, after some serious PT, I can eventually get back on the bike. I've been off ever since my knee started acting up last winter. I'd thought I'd just sprained my knee (and potentially dislocated my fibula) when I slipped on some ice, so I didn't worry until it never got better.
Fortunately, I record all of my lectures and have several semesters worth saved. If recovery takes longer than the two weeks the surgeon says I'll be off, I can just either start uploading lectures from last spring or make new recordings and teach it as if it were an online course. Students don't like that as well, but it can work in a pinch.