Bad knee damage due to car hitting me while bicycling

Hello injured-knee readers,

I've some general questions about what I might expect in time.

I've been an avid bicyclist since 1971. [I'm 60 now.] It was 8.5 weeks ago when a careless driver hit me on my left side while I was bicycling. My left knee got really damaged internally; a large, very painful hematoma quickly formed on the lower right leg, and two fingers on my left hand were badly sprained or jammed-- now the fingers (middle and ring) are deformed, misshapened, and in pain in spite of immediate medical care and follow-up "care" by quite young, fairly new orthopedists who are residents in the VA hospital in which I get medical care.

From the accident site, I was taken in an ambulance to a hospital where X rays on the day of the accident (left hand and left knee) and two days later (left knee) showed no broken bones. I was told that the X rays only showed minor degenerative changes in my left knee. Twenty days after the accident an MRI scan of the left knee revealed to the radiologist(s):
- MCL: grade 3 tear
- LCL: grade 1 tear
- ACL & PCL: each has a partial tear
- lateral meniscus: small tear
- bone bruising on the knee joint end of the femur. [I was later told this could lead to delamination which I suppose means that the articular cartilage could come off the femur.]
- no loose pieces inside the knee

For almost 6 weeks I wore a soft form type, ankle-to-hip leg immobilizer which kept my left leg straight and stiff. I couldn't bend my left leg at all because of the pain. It was ~ 12 July when I started the simple left leg exercise to restore and increase the range of motion. The 2nd young orthopedist I met with earlier this month told me to sit on a bed, extend both lower legs out horizontally, use the right foot to support the left foot/leg, and lower and raise the lower left leg with support and power from the right foot/leg. I'd say I can only achieve an angle of ~ 60 degrees before the pain under the knee cap hits and I don't go past that start-of-pain point. [I do this exercise 3 times a day and use 2 blue gel cold packs on the left knee after each session.] [The under kneecap pain feels as if something in the knee wants to push off the kneecap. Maybe some would say it's a super-fullness feeling inside the knee.]

I have no idea why there's pain with bending the left leg. I suppose it might be due to the fact that the left leg was kept straight and stiff for so many weeks, or due to the multiple internal ligament and other injuries, or maybe due to tissues that are fully or partly healed by now and are not yet used to being pulled on or stretched, or maybe all of these together-- I don't know. [Tell me if you have ideas about the pain.]
Will there be during upcoming weeks and months only a very gradual, slow increase in the angle I can achieve in the simple unloaded leg exercise I do? I know that an attempt at bicycling is probably in the distant future for me. [I read on the Internet, that with knee injuries, one must be able to bend the leg to at least 100 degrees in order to ride a bicycle.][The orthopedist told me that if, in the future with the resumption of bicycling, I have pain or difficulty in riding, then an orthopedist would have to do an endoscopic examination of my left knee and maybe make surgical changes. There's never been knee endoscopy for me.]

Just the other day I felt I should try to use a shorter, hinged knee brace. So I'm using that kind now and it's made walking easier than the difficult, very limited kind of walking I did with the straight, stiff leg immobilizer. Since maybe two days after the accident I found I could easily stand and walk pain free while keeping my left leg straight and stiff, so perhaps that's been a good sign from early in this otherwise bad episode. My knees have long made snapping sounds when I turn my legs a bit and I'm not sure if the snapping sounds are more frequent now after the accident. I suppose the pain-free snapping means my knees have some laxity-- I don't know. [Or did so many decades of bicycling cause laxity and snapping sounds?]

Have any of you had a similar number of simultaneous internal knee injuries and damage?

How did treatments and physical therapy proceed and unfold for you?

How is orthopedic care tailored to one's activity level and to one's physical sport passion? [I also like to walk fast and far, to dayhike and possibly backpack again someday.]