knee brace with drop locks

Hi all,
I have been asked to provide a knee brace for a 79 year old woman who has a complete (90%) quad disruption for several years.  Her patella is actually located laterally on the knee joint.  She is unable to extend against gravity and she has a tendency to buckle and fall.  Doctor specifically requested a knee brace with drop locks.  I’ve looked at Townsend and may go with their lock but any suggestions on something lighter for this older woman would be helpful.  Neoprene with hinges and drop locks??  I’ve used DJ before but the lock is a bit complicated.  Would appreciate any suggestions.
Thanks
Karl Entenmann, CPO
Preferred O and P
Federal Way, WA