Orthopedic Coding Alert

If you-re eager for feedback on your coding without the stress of auditors, here's your chance.

Decide which CPT and ICD-9 codes you would choose for your orthopedic surgeon for this case study, shared by Mariellen Murray, chief operating officer at The Florida Knee and Orthopedic Centers, and then check your answers against the expert's below.

Pre-op diagnosis: left knee DJD varus

Post-op diagnosis: left knee DJD varus

Operation: partial knee resurfacing with patelloplasty, diagnostic arthroscopy, plastic skin closure, pain pump catheter placement

Components: (see hospital operative form for sizes and types)

Procedure: After satisfactory anesthesia, the leg was placed in the leg holder, prepped and draped in the usual sterile manner. Tourniquet inflated. Diagnostic arthroscopy performed showing medial compartment degenerative changes and no other abnormality.

A straight longitudinal incision was made parallel to the patellar tendon. Medial parapatellar arthrotomy performed. Fat pad partially resected. Capsule and collateral ligament elevated subperiosteal to expose proximal tibia. Patelloplasty performed. Hohmann retractor inserted.

Posterior femoral condyle removed with saw. Femoral and tibial osteophytes removed with a rongeur. Proximal tibia prepared with a saw and burr until appropriate-sized trial could be inserted.

Distal femur sized with drill guide, and pilot hole was drilled. Femoral condyle prepared with a burr. Trials inserted. Knee extended and put through its range of motion to determine alignment and ligament balance.

Trials removed. Bone irrigated with pulsatile lavage and dried. Tibia and femoral components inserted with bone cement. Excess cement removed. Knee held in extension until cement cured. Percutaneous pain pump catheters were placed intra-articular and subcutaneously before closing.

Wound irrigated and closed in layers with plastic technique, which included a subcuticular skin closure. Bandage applied, tourniquet deflated.

The surgeon first documents a diagnosis of "left knee DJD varus." Translation: The patient has degenerative joint disease (DJD)m and the distal portion of the extremity is deviated inward, making the patient appear bowlegged (varus).

ICD-9 solution: You should report 715.36 (Osteoarthrosis, localized, not specified whether primary or secondary; lower leg) for the DJD and 736.42 (Genu varum [acquired]) for the varus deformity, says Heidi Stout, CPC, CCS-P, director of orthopedic coding services at The Coding Network LLC.

DJD: The doctor documents left knee DJD. Under the entry "Degeneration, degenerative" in the ICD-9 index, you find "joint disease (see also Osteoarthrosis)" and 715.9x.

You should always check codes listed in the index in the tabular list to verify they-re the best choice. If you check the listed code, 715.9x (Osteoarthrosis, unspecified whether generalized or localized), in the ICD-9 tabular list, you-ll see that this is an unspecified code. ICD-9 conventions state that you should use unspecified codes only when the documentation doesn't offer you information to choose a more specific code. The surgeon documented the diagnosis as left knee DJD, indicating the DJD is localized, so you should look for a better coding option than 715.9x.

How: The DJD index entry includes the note "see also Osteoarthrosis." According to ICD-9 coding guidelines, the "see also" instruction tells you that you may reference another main term for additional possibilities. In other words: Look up the other term, and you may find a more accurate code for the condition.

Under the index entry for osteoarthrosis, you see 715.3x for "localized." A quick scan of 715.3x (Osteoarthrosis, localized, not specified whether primary or secondary) and the surrounding "localized" codes in the tabular list reveals that you-re on the right track with "not specified" code 715.3x.

Why: Without documentation of whether the osteoarthrosis is primary or secondary, you can't report more specific codes 715.1x (Osteoarthrosis, localized, primary) or 715.2x (Osteoarthrosis, localized, secondary).

But you aren't finished yet -- 715.3x requires a fifth digit. For ICD-9's fifth-digit options for this code range, "6" (lower leg) is the most accurate choice for knee DJD. So you should report 715.36 for the left knee DJD.

Varus: The surgeon also documented a varus deformity related to the DJD. You won't find "varus" in the ICD-9 index, but you know that varus indicates "bowlegged." The ICD-9 index points you to 736.42 for this term. When you check this code in the tabular list, you see the descriptor "Genu varum [acquired]." Genu means knee, and genu varum means bow knees or bow legs. The varus is related to the DJD (acquired), rather than congenital, so you know that 736.42 is the best option.

When deciding on the proper CPT code, note that the surgeon documents degenerative changes and resurfacing arthroplasty for the medial compartment only.

What this means: This op report provides "a somewhat abbreviated but adequate description of a unicompartmental knee arthroplasty," which you should report with 27446 (Arthroplasty, knee, condyle and plateau; medial OR lateral compartment), Stout says.

In the op report, the major arthroplasty indicators are the following, Stout says:

- Patelloplasty performed.

- Posterior femoral condyle removed with saw. Femoral and tibial osteophytes removed with a rongeur. Proximal tibia prepared with a saw and burr until appropriate-sized trial could be inserted.

- Distal femur sized with drill guide, and pilot hole was drilled. Femoral condyle prepared with a burr.Trials inserted.

- Tibia and femoral components inserted with bone cement.

Watch for: The documentation describes several procedures, but the Correct Coding Initiative (CCI) bundles many services into 27446.

For example, the report shows that the surgeon performed a diagnostic arthroscopy, but you should not report this service. CCI bundles 29870 (Arthroscopy, knee, diagnostic, with or without synovial biopsy [separate procedure]) into 27446.

Although the bundle does have a "1" modifier indicator, meaning that you may override the edit, the circumstances don't merit it. You should override the edit only if the orthopedist performs the diagnostic arthroscopy "separate procedure" in a way that's distinct from other services performed that day. For example, the orthopedist performs bilateral diagnostic arthroscopies, but only performs arthroplasty on the left knee. You should bundle the left knee arthroscopy into the left knee arthroplasty. But you may report the right knee arthroscopy separately, using either modifier 59 (Distinct procedural service) on 29870 or modifier RT (Right side) on 29870 and LT (Left side) on 27446.

Coding round-up: Your orthopedic claim for this case study should include 27446, 715.36 and 736.42.