Sorry about your fall.
I installed a Drotto Boat Latch on my trailer. It eliminates the need to climb on my trailer to release my boat. A rope can be attached to it and it can be released from the the cockpit seat.
I use a retractable dog leash attached to the boat and just trip the Drotto release when I launch. I will never have another trailer without one on it. There are videos on YouTube showing them in use.