Test Yourself: Total Knee Replacement (TKR) Coding

Can you tackle an op note like this one we got our hands on? Relax. We help you break it down into 3 steps.

Although you may be accustomed to TKR op notes, an unusual case might send you into a panic. Take a deep breath, and we’ll have you breezing through the challenges that atypical TKR op notes present, like coding for a necrotic bone graft from a prior fixation.

First, Read the Op Note

Review the op report and code the procedure on your own. Then check out our expert advice below.

Preoperative diagnosis: Status post severe bicondylar proximal tibia fracture, and post open reduction internal fixation with bone grafting (failed).

Procedure overview: The surgeon scheduled a patient for hardware removal (from a tibia fracture), as well as a total knee replacement. When he opened the patient, he found it necessary to perform major deep hardware removal, tibial tubercle reconstruction, trabecular metal coil insertion, wedge medial tibial base plate, and long stem tibial component (total knee replacement).

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The pertinent details of the op report follow: After I opened the patient, I noted an obvious nonunion of the tibial tubercle. I removed the tibial tubercle wires and removed the plates and found that the massive amount of bone grafts that we had used intraoperatively had not consolidated and there was a tremendous amount of necrotic bone. I ununited the medial tibial plateau and discarded the large (3-cm) piece.

I used a trabecular bone proximal tibial reinforcer and shaped the inner tibia, removing some of the remaining cancellous bone from the proximal tibia to incorporate the trabecular cone into the proximal tibia.

We placed a rod up through the femur, inserted the distal femoral cutting block jig, cut the distal femur, and measured the femur to a size F. We cut the anterior-posterior femurs and chamfered them. We removed medial and lateral meniscal remnants and the anterior-posterior cruciates.

We again debrided the proximal tibia and found that the anteromedial tibia was deficient for 5 or 6 cm. With the rod in place down through the tibia, we cut the proximal tibia at about 1 cm. We reamed the tibial canal to 13 mm for the rod and left the rod in place.

We shaped the inside of the proximal tibia to accept a cone, and then set the distal portion of the cone medially on the tibia and inserted it inside of the proximal tibial metaphysis. We settled on a #17 polyethylene that allowed us to fully extend and flex with stability medially and laterally in both flexion and extension.

We then addressed the tubercle nonunion. We drilled two holes in the trabecular metal and passed two wires through the holes and back out. We weaved the wires through two holes in the tibial tubercle, affixing the tubercle to the anterior tibia and trabecular metal.

We drilled another hole distally in the anterior tibia for another wire, and then inserted cement in a press-fit fashion on to the tibial surface with a cone and longstemmed tibial component in place. The femur, tibia, and femoral components fit nicely with the 17-mm insert, and we used a posterior cruciate replacement-type prosthesis. After the tibial side cement cured, we cemented on the femur and the patellar button (a 26 mm). Then we reattached the tibial tubercle. I took some bone from the femur (an autograft) and packed it in around the tubercle.

Break Op Note Down Into 3 Steps

This op note describes “much more than a TKA,” warns Mary Baierl, RHIT, CPC, CCA, CMT, professional medical coder at BayCare Clinic, Orthopedic Surgery and Sports Medicine in Green Bay, Wis.

Step 1: Report the knee replacement. Although the surgeon discussed the tibial nonunion first, you should code the total knee arthroplasty first. Not only is this the higher-paying procedure, but it was also a complicated surgery and the main intent of the surgeon’s visit to the OR with the patient.

You should report 27447 (Arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing [total knee arthroplasty]) for the knee replacement, Baierl says.

Address Procedure’s Complex Nature

Step 2: Because the surgery was vastly complicated by the fracture nonunion and the amount of necrotic bone, the surgeon didn’t perform a standard knee replacement. “The necrotic bone graft from the prior fixation makes things challenging, if not more difficult,” Baierl says.

Therefore, you should append modifier 22 (Increased procedural services) to 27447, says Heidi Stout, CPC, CCS-P, director of orthopedic coding services at The Coding Network LLC.

When you append modifier 22 to a CPT code, you’re telling the payer that you went over and above what the code describes, and therefore you deserve additional reimbursement. Ask your surgeon to determine how much additional time or effort he spent on the knee replacement.

Example: If the surgeon tells you that he went 20 percent over the normal work required for a knee replacement, you should request 20 percent more reimbursement than 27447 normally pays. The relative value units for this code are 40.38. Multiply that times the 2009 conversion factor ($36.0666), and you should expect $1,456. If the surgeon performs 20 percent more work, you’d bill 27447-22 and request $1,748 instead of the standard $1,456.

When you submit your claim with modifier 22 appended, remember to send a letter from the surgeon in which he describes the unusual nature of the surgery, along with the op note.

Treat the Nonunion

Step 3: To collect reimbursement for the tibial nonunion repair with autograft, you should report 27724- 51 (Repair of nonunion or malunion, tibia; with iliac or other autograft [includes obtaining graft]; Multiple procedures).

Because the Correct Coding Initiative (CCI) does not bundle 27724 into 27447, you don’t need to append any additional modifiers to the procedures. You should not separately report the hardware removal (20680). CCI bundles this code into 27447. If you need to remove the hardware to accommodate a more comprehensive procedure, then you should not separately report the hardware removal, according to the AMA.

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