I’d think that (other than a custom frame) a frame size appropriate for the OP’s torso might be a reasonable starting point. Seat height and fore/aft position along with stem height and reach are reasonably easy to adjust. Another consideration would be the proportional change between the “knee to hip” length and “knee to ankle” length. Crank length may need to be taken into consideration 🤔.
It might be reasonable for the OP to consult with someone with more than amateur knowledge of the anatomic physiologic aspects of cycling. The opinion of a trained kinesiologist would also be helpful. Before I did any serious cycling (if I were to have had this type of surgery), I’d be sure to get clearance from my “cosmetic orthopedist” to ensure complete healing of both femurs!