Question: Our physician performed knee arthroscopy (29879) in the lateral and medial compartments using two separate portal sites. He wants to bill 29879 twice, with distinct procedural service modifier -59 appended to the second 29879. Is this appropriate? Ohio Subscriber Answer: The American Academy of Orthopaedic Surgeons notes in its Global Service Data 2002 guide that you can only report one chondroplasty code per joint, regardless of the number of compartments involved. The guidelines read: "Debridement of articular cartilage (chondroplasty) in the same compartment where meniscal repair or excision is performed is considered included (bundled) and should not be coded. Chondroplasty procedures can only be coded one time per joint, no matter how many compartments are debrided. Abrasion arthro-plasty codes are appropriate when the procedure exposes bleeding subchondral bone." With this in mind, report 29879 (Arthroscopy, knee, surgical; abrasion arthroplasty [includes chondroplasty where necessary] or multiple drilling or microfracture) only once.