Hi Paul
I broke my patella last March,it was in 3 pieces and displaced,so i did need the surgery,i too was in a cast, ankle to thigh for 7 weeks, was non weight bearing,and couldn't do any exercise during this time,after a further 2 weeks of non weight bearing, and just heel slides as exercise,i then started PT.
4 1/2 months post-op i had full ROM,so my PT released me,saying i was now ok,i was far from ok, i had full ROM but very little else, and my leg strength was crap.
Rom is not the be all and end all,as i came to realise,you have to work on building back the muscle and strength in your leg equally as much,i had a poor PT,whom i don't think had much experience of patella fractures, therefore he worked on ROM, and only ROM.
After lots of research on the internet,i found lots of links for different exercises,and i also discovered this amazing site,though i usually post on( Bone breaks around the knee),that is more about breaks and you would probably gain more info from there.
What you are experiecing is what most of us have gone through, the stiffness/tightness is quite normal, mine is sometimes a little bit stiff now at times even at 10 months post-op.
What you have to remember is,that this is a serious injury,and will take a long time to heal,and it cannot be rushed,it will require lots of hard work and exercise,but you will get there in the end.
you will get lots of info and advice on this site, but bear in mind that no two injuries are the same,nor do we all heel the same,so what may be good for one person may not necessarily be good for you.
So listen to your Dr, your PT,and your body,keep up with the exercising,without overdoing it,and you should be fine.
This is a long frustrating journey,and like everyone on this site seems to say,it's a marathon not a sprint,so prepare yourself for a long journey, i can assure you that there will be light at the end of the tunnel but maybe not as soon as you expect.
I can relate to all you are saying about the straight leg raises,these were painful to me also, and it felt like i had a heavy weight on my leg,you will probably also have the stair climbing issue, as we all seem to have difficulty managing the steps without having pain or difficulty, but this also gets easier with time.
I am now 10 months post-op, and almost "normal" but i now have HW issues, which thankfully you won't have.
Hope this helps, and i wish you all the best for a speedy recovery.
Regards.
Coral.