Hi New Mexico Gn — congrats on doing TKR surgery.

First advice is to not take bikers’ advices. We are all different and don’t know you. Some TKRs don’t work as well. That said last two posters had what seems some pretty good advice

Second, talk with your therapist assuming you are still going. They are in the best position to know you and your limitations. Your surgeon might be helpful too however the PT person knows you best at this point. They should give you guidelines about stationary and outdoor cycling. Perhaps just spinning indoors for a while is best...they should know. Let them see your knee/leg on a stationary bike for guidance. Then they can offer suggested timings for spinning/riding, effort needed and generally give you a plan to get you where you want to go.

Third, once you ride on the street consider Speedplays. I’ve used them for 6 years and they allow movement of shoes better than others.

Good luck. I’ve ridden 43,000 miles after TKR without an issue although didn’t start outdoor riding until 3 years after TKR. Did do indoor spinning right away with few issues which is why say we are all different.