Hello Rameez,
I had also my patella shattered in 5 pcs, I had surgery a week after (due to all surgeons where in vacation, since I had my injury at the end of July 2018), I have 3 screws + 2 wires. My surgeon told me I can start to do weight bearing having the brace on the day after the surgery and using crutches to load the leg while is conformable for me.
I have my progress documented here:
https://www.kneeguru.co.uk/KNEEtalk/index.php?topic=75266.0 I would say that for any persons going thru patella fracture and surgery, at first they should start to regain the ROM and keep the quadriceps muscles trained.
I was walking thru the house with crutches from the 7th day after surgery, but this was because I needed to get some ROM (I think like 30 degrees) and because I waited 1 week for the surgery I had my quadriceps atrophied so I had to restart them...
There are isometric exercises to keep the muscles trained, I think it would be helpful to find a PT to show you some, or go on youtube and search. And for ROM the best one used for me was to have my leg straight on a hard surface having a sock on my feet and using a towel to pull the ankle towards me, having the brace locked at the ROM recommended by the OS (I started with 30 degrees).
Keep us posted of your progress.