Anesthesia Coding Alert

Question: What are the correct codes to report for the surgery, anesthesia, and diagnosis for the following case:

The doctor provides anesthesia for surgery involving repair of tibial malunion with autograft. This patient had surgery previously to treat the fracture and presented with continued problems, for which the surgeon assigned a post-operative diagnosis of displaced bicondylar fracture of the left tibia during a subsequent encounter for the closed tibial fracture with malunion.

The operative report indicates an incision was made over the iliac crest, and the muscle was stripped to reveal the bone surface where the cancellous bone was harvested and configured to the shape of the defect to repair the malunion. Internal fixation was used to secure the bone graft.

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Answer: For the surgery, report 27724 (Repair of nonunion or malunion, tibia; with iliac or other autograft (includes obtaining graft)). CPT^® code 27724 crosswalks to three different ASA code options:

• 01392 (Anesthesia for all open procedures on upper ends of tibia, fibula, and/or patella), 4 base units;
• 01480 (… open procedures on bones of lower leg, ankle, and foot …), 3 base units; and
• 01112 (… bone marrow aspiration and/or biopsy, anterior or posterior iliac crest), 5 base units.

ASA code: In this case, the appropriate anesthesia code to use is 01112.

Why? According to comments under 01112 in the American Society of Anesthesiologists (ASA) Relative Value Guide^® (RVG), the coder “may report code 01112 when small (button or dowel) graft obtained from iliac crest.” Since this option offers the highest base units, you should report 01112.

Diagnosis roundup: For the diagnosis, assign S82.142P (Displaced bicondylar fracture of left tibia, subsequent encounter for closed fracture with malunion). Remember, this is a subsequent encounter for fracture with malunion, so you’ll want to use “P” as the ICD-10 code’s 7th character. While anesthesia coders typically opt for “A” as the 7th character when coding diagnoses, this corresponds to initial encounter, which is not the case in this scenario.