I got this one: LightEase Memory Foam Leg Support and Elevation Pillow w/Dual Handles for Surgery, Injury, or Rest https://www.amazon.com/dp/B07ZNPL5HZ/ref=cm_sw_r_cp_api_i_E56BVPM7A95WEKXJNF37?_encoding=UTF8&psc=1

I put my foot as far forward as possible so that my knee is hanging free. It is uncomfortable but necessary for extension