The majority of OSs would like 90 degrees at 6 weeks. You have surpassed that already. I don't think the Dyna splint is necessary and may further aggravate your healing knee.
Swelling is restricting your knee's bending, not adhesions. Spend less time trying to bend it and more time icing and elevating, and that bend will come in naturally as your swelling goes down. Can you bend a water hose full of water with the nozzle cut off? Nope. Open up the nozzle, letting the water out, and you can roll it right up. Your knee is the same way. Get the 'water' out and it'll bend better. Exercising and forcing it will not do that, it will just cause more swelling. Gentle movements and walking is all the exercise it needs to recover.why isn't my leg moving, is it scar tissue?