Conversion of UKA to TKR

Question:

I took a significant leave from coding orthopedics; now, I'm back in the trenches coding for ortho. Has the coding recommendation for revising a unicompartmental knee arthroplasty to a total knee replacement changed? I'm confused; our surgeons gave me an AAOS Now Article from 2023, and I have the CPT Assistant article from 2013. Can you please advise?  

Answer:

In the hip section of CPT, we have code 27132 (Conversion of a previously open procedure to total hip arthroplasty). Unfortunately, no code exists in the knee section of the CPT book. 

In June 2023, an AAOS Now article was published that addressed this question with two different coding directions. 

· The first coding option outlined, if the conversion is simple with primary implants, is to report CPT 27447 and append modifier 22 for the increased work due to the altered field. 

· The second coding option outlined states is to report code 27487 if bony defects require augments or stems. 

KZA understands that the June 2023 article was superseded by a revised article removing the published recommendation. The revised article can be found on the AAOS website in the Archives section for June 2023. 

However, a CPT Assistant addressed this question in July 2013, stating to report this coding scenario with CPT 27487 and append modifier 52 (reduced services). 

KZA understands why you are confused! As you see, there are now two different sources with three different coding recommendations, which leaves a coder to wonder which coding guidance to follow when having to code a conversion of a UKA to a TKR. It's not a great spot for a coder to be in when you have a case to code! While the CPT Assistant from July 2013 is older, KZA recommends following the AMA CPT article until the AMA publishes an updated article. A conversion of UKA to a TKR/TKA is 27487-52. 

*This response is based on the best information available as of 11/14/24.