Sorry, yes meant I have come across the scenario. I like to ask people's thinking process or what they think it should be coded as before just answering. I don't do facility billing however, there are no conversion codes for the knee and shoulder like there are for the hip (27132). The last guidance I knew of was to code the TSA 23472 and add a 22 for increased services/additional work according to the documentation. It wouldn't be 23474 because the TSA was already removed in the first stage. The first case was probably 23335/20704.
I wish there were codes for the knee and shoulder for this scenario. I see the provider's point where they feel it should be 23474 because the spacer was acting as the temporary joint and a lot of them, like when they do the knee are articulating/functional. In some cases, they even leave the functional spacer in and don't even do another "final" implant. That was one provider's discussion with me, he was like, I can leave this in and it is essentially acting as the final implant even though it is an abx "spacer". The codes have not kept up with the technology and procedures for total joints.
Unfortunately, the 20705 can't be reported with 23472 which makes no sense to me and hasn't since they came out with those drug device codes.
Did you check Coding Clinic or CPT Assistant at all? I don't think there is new guidance, but I have not checked lately.