All i can say Kev is once limbs have broke they are rarely the same again ....
i fractured my left ankle back in 2002 , and had two pins put in it to hold it together whilst the plaster set ....... the pins remain inside my ankle to this day , and my left ankle joint is still bigger than my right one ........ and every now and again the joint becomes pretty sore , and let's me know it's there.
However a bloke in the hospital at the same time had a worse injury than mine .... he'd broken several parts of his leg , had plates fitted , and went swimming to recuperate on a daily basis ...... he said that helped him immensely , and really i should have done that too .
So here's my advice .......
put your foot down on the floor again as SOON as you possibly can again AFTER plaster has come off , and the injury has 'healed' ...... do it slowly , as it will be painful , and put a bit more weight on it on a gradual basis , the doc will advise this too ........ that's something again which i neglected to do , and i regret now , because it would almost certainly have aided me ............. the consultant told me a bone only takes around 17 days or so to heal , but the plaster remains on for longer (around six weeks) as a precaution.
and consider takin' up the 'swimming' thing , it works all your limbs , and that bloke i'm talking about reckoned it worked absolute wonders for him!