Orthopedic Coding Alert

Question: Operative notes indicate that the surgeon performed a level-four inpatient office evaluation and management (E/M) service for a new patient with left knee pain. This led to the patient being scheduled for a knee arthroscopy the next day. What is the proper code for the arthroscopy?

Massachusetts Subscriber

Answer: The correct code for the procedure is in doubt, as you don’t have evidence as to the purpose of the arthroscopy: diagnostic or surgical.

When the notes indicate that the surgeon performed a diagnostic knee arthroscopy, you’d report 29870 (Arthroscopy, knee, diagnostic, with or without synovial biopsy (separate procedure)). According to Codify, a diagnostic arthroscopy occurs when “the provider examines the inside of the knee joint with an arthroscope to assess for causes of pain and limitation of movement. If necessary, she takes a sample of the synovial tissue that lines the joint and submits it to a laboratory for analysis and diagnosis.”

So if the encounter notes indicate that the arthroscopy was purely diagnostic, and did not lead to any further treatment of the knee, you’d report:

• 29870 for the scope.
• 99204 (Office or other outpatient visit for the evaluation and management of a new patient, which requires these 3 key components: A comprehensive history; A comprehensive examination; Medical decision making of moderate complexity …) for the E/M.
• Modifier 57 (Decision for surgery) appended to 99204 to show that the E/M and the surgery were separately identifiable services.

Surgical session? If, however, the procedure is surgical rather than diagnostic, then coding options open up — considerably. There are more than a dozen surgical knee arthroscopy codes, including (but not limited to):

• 29871 — Arthroscopy, knee, surgical; for infection, lavage and drainage 
• 29874 — … for removal of loose body or foreign body (eg, osteochondritis dissecans fragmentation, chondral fragmentation)
• 29880 — … with meniscectomy (medial AND lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty), same or separate compartment(s), when performed
• 29885 — … drilling for osteochondritis dissecans with bone grafting, with or without internal fixation (including debridement of base of lesion).

So if the notes indicate that the surgeon performed arthroscopy of an infected left knee that required lavage and drainage, report 29870 for the scope, in addition to 99204-57.

Remember: Whether it’s diagnostic or surgical, append modifier LT (Left side) to the knee arthroscopy code, if the payer requires laterality modifiers.