One way to make your specialty shirt is to take a normal dress shirt or front open shirt and remove the buttons. Next, you should get some Velcro and cut it into small strips. Just do not make them too short.
After sewing the Velcro on, cut the shirt on the injured shoulder side to allow for better placement of the shirt. Attach more Velcro straps to close the two sides together and keep the shirt on securely.
Another way is to get some over-sized T-shirts and cut the seam from the neck to the shoulder. Just do not cut the top of the sleeve as you want it in place to help keep the T-shirt on.
Cut underneath in the armpit area to make the hole larger and easier for you to slip your injured arm through. You can also cut down the injured side a little and add Velcro strips on both sides to close the shirt off once it is on your body.
Making the shirt just takes a little time, patience and some sewing talent. It is easy to make a mistake and cut too much so be careful and take your time.
Lastly, you can always visit www.renovamedicalwear.com for you post surgery clothing needs.