I have eight screws and two titanium plates in my fretting hand middle finger from January 2014. I had surgery (obviously), 3 months of phys therapy, endless stomach probs from the meds, and I was in incredible pain even with it.
While I was recovering/rehabbing, I used to dream about practicing, I would dream about bass lines, about playing and practicing. I went to band practice to listen and get some hang time, watched lots of Scott's Bass Lessons vids and did EXACTLY what my doctor said.
EXACTLY.
I went through hell in phys therapy, but did it EXACTLY like they said, every hour for ten minutes as they said, for months.
Three months later I was starting to get some movement back in my fretting middle finger as the phys therapy paid off. I showed my orthopedic surgeon how I fret the bass and asked if he thought there would be any problem with me doing that as part of my recovery and he encouraged it saying it would be an awesome way to get flexibility back in my hand.
But I asked first before just doing it and showed him how I fretted notes rather than just jumping into it.
It took my much faster than expected to get back up 100% - like 6-7 months. Since then I've continued practicing, playing and never had an issue with my fretting fingers at all - check out my video channel below for proof lol.
The BIG takeaway is that if you want any chance on recovery, do exactly what your doctor tells you, how he or she tells you to do it, when they tell you to do it.
Do everything the physical therapist/sadist tells you to do, no matter how much it hurts or how often you have to do it.
During the recovery period ask your doctor his opinion before doing ANYTHING with your injured hand. Don't assume any repetitive motion -like fretting a note - is OK.
Get ready to be frustrated, bored and anxious - at least I was. I had NO idea if I would be able to play at the level I was used to, and if not, I decided that I wouldn't want to play at all (but that's me, your milage may vary).
Good luck!
I hope you heal up fast with no complications and get back on the bass soon!