It does take awhile to recover from those mis-steps, sometimes a setback of a couple weeks with the pain. 4 weeks after I had ORIF surgery for a broken elbow, I fell on the incision and it became very painful. When we got home, I went for an x-ray and everything was fine, other than the pain, and I recovered from that.
Recently I broke my femur, right above my knee replacement and I was very worried I had damaged my knee. Once again, the knee replacement was fine and solid, but oh the pain from a broken femur and then surgery. 5 months later and I'm still having some pain in my thigh.
Having said that, I hope your knee replacement is still solid and the pain doesn't last too long. Maybe they will do an x-ray at your next surgeon follow-up to give you peace of mind.