Problem w/ the setfield function

I have three variable outputs (healthy_exposed, pus, necrotic) that I want to enter into my structured field array in the third element that I've left empty, my setfield function at the bottom isn't doing that, any pointers?

healthy_exposed = 3 ;      
pus = 2;
necrotic = 1;

patient.name = {'John Doe'};
patient.dob = {'04-Apr-1957'};
patient.date = {'01-Feb-2011'; '25-Apr-2012'; ''};
patient.percentages={ [02 08 09]; [23 20 24]; []}
patient.notes = {'Treated for diabetic wound ulcer'; 'Treated for obesity and diabetic wound ulcer'};
patient;

patient=setfield(patient,{1,3}, 'percentages', [healthy_exposed, pus, necrotic]);

Answer 1

[per isakson]

Why use setfield? Does this do what you want?

    patient.percentages{3} = [healthy_exposed, pus, necrotic];