Question Summary:
Is it better for the one who can stand but cannot perform sajdah to pray sitting or standing?

Question Detail:

I had met with an accident around three years back, due to which my leg was broken. After getting the operations done now 
Alhamdolillah I can walk quite normally, but my problem is that till now I can't sit in prostration during salah. Due to this I sit in a chair to perform my salah. One day our imam said that if I can stand then I should stand and pray whereas for sajdah and sujood I can sit on the chair and complete my salah. When I tried doing the same way I was not convinced bcas when I was standing for the prayer in jamaat with my chair it was looking odd because due to my chair I had to move ahead of my fellow musallis and while going for ruku my head was also touching the rear of the musallis standing ahead of me. I totally confused what to do in this scenario. Please give me a proper solution for my problems. 
Waiting for your kind cooperation and guidance in this regard. 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
This question has already been answered previously. Please see Fatwa #19265 at the following link: http://www.askimam.org/public/question_detail/19265 
And Allah Ta’āla Knows Best
Sohail ibn Arif,
Student Darul Iftaa
Chicago, USA
Checked and Approved by,
Mufti Ebrahim Desai.