Question: If the orthopedist debrides a ganglion cyst of the posterior cruciate ligament, should I report 29877? Kansas Subscriber Answer: Code 29877 (Arthroscopy, knee, surgical; debridement/shaving of articular cartilage [chondroplasty]) seems like a reasonable code choice because it specifically includes the word "debridement." But you should reserve this code for when your orthopedic surgeon debrides or shaves cartilage in the knee. In fact, the August 2001 CPT Assistant states, "Code 29877 describes smoothing of roughened or damaged cartilage surrounding one or more of the articular ends of the bones of the knee joint by debridement or shaving." In the case you describe, the surgeon debrides the posterior cruciate ligament (PCL), and this doesn't qualify as cartilage. Most likely, the cyst is synovial-lined tissue. Consequently, your best code choice is 29875 (- synovectomy, limited [e.g., plica or shelf resection] [separate procedure]).