CPT 29879

My surgeon performed arthroscopic patial medial, partial lateral meniscetctomies and abrasion chondroplasty of the chondral surface including the thochlea, femoral condyle and underside of the patella. For the abrasion chondrolplasty, he submitted CPT 29879. He is being told be staff at the surgery center that they are billing 29879 three times because the chondroplasty was performed on three different surfaces. We've never billed it this way, but I'm curious to know if we're missing some deserved revenue here. Your comments would be very helpful.

Thanks.