Coding for a Knee Arthroscopy

Vol. 18 •Issue 4 • Page 9
Coding Corner

Coding for a Knee Arthroscopy

Before assigning codes to a claim, be sure to check the national CCI edits to identify bundled codes.

Preoperative Diagnosis:Degenerative tear of the medial meniscus, left knee.

Postoperative Diagnosis:Degenerative tear of the medial meniscus and chondromalacia of the patella and medial femoral condyle, left knee.

Procedure Performed:Arthroscopic partial medial meniscectomy, left knee.

Operative Technique:Under adequate spinal anesthesia and with the tourniquet on the left lower extremity, the left leg was scrubbed, prepped and draped sterilely. With the tourniquet up, a drainage needle was placed in the superior lateral pouch. The 30-degree arthroscope was introduced anterior medially and a probe anterior laterally.

Examination of the knee joint showed a few small floating cartilage fragments in the joint. There was considerable loss of articular cartilage on the lateral facet of the patella. Rough edges were smoothed with the Dyonics debrider, but the bone was not eburnated or exposed. A plica in the pouch area as well as a very thick one in the medial gutter was resected with punch as well as Dyonics debrider. In the lateral compartment the meniscus was probed and found to be intact. In the medial compartment there was a split tear with a radial tear as well in the posterior medial corner. This was debrided back to a stable rim using straight and side-cutting punches followed by the Dyonics debrider to further smooth out the remaining rim. The cartilage also on the medial femoral condyle was moderately damaged down to, but not exposing, the bone on the weight-bearing surface. This was also smoothed back with the debrider. The wound was copiously irrigated with normal saline throughout the procedure and vacuumed of all debris.

The arthroscopy was then discontinued and the portals closed with staples. A sterile dressing was applied. Patient tolerated the procedure well and returned to the recovery room in good condition.

ICD-9-CM Diagnoses


Degenerative tear of the medial meniscus, left knee

717.3 Unspecified derangement of medial meniscus


Degenerative tear of the medial meniscus and chondromalacia of the patella and medial femoral condyle, left knee

717.2 Derangement of posterior horn of medial meniscus

717.7 Chondromalacia of patella

733.92 Chondromalacia

CPT Coding

Under “procedure performed,” the surgeon states that he performed a partial medial meniscectomy of the left knee arthroscopically. Since arthroscopy identifies the procedure performed, you will look in the CPT index under that term. These codes are divided into Diagnostic, Surgical and Unlisted. Obviously you will look under Surgical and then for the location of the procedure, which was the knee. As always, you will have several choices as to what type of a knee arthroscopy was performed, as the codes range from 29871-29889.

You will review each of these codes, which can be found in the Surgery section of the CPT code book under Musculoskeletal System. The main description is listed under 29871 (arthroscopy, knee, surgical).

Checking all of the indented codes under the main description will lead you to the correct code.

29881 with meniscectomy (medial OR lateral, including any meniscal shaving)

The surgeon also states that he debrided the articular cartilage of the patella and the medial femoral condyle. (The patella is a different compartment than the medial femoral condyle or medial meniscus.)

The American Medical Association (AMA) states that the chondroplasty may be coded separately if performed in a separate compartment from the meniscectomy—in this case, the patella. The code assignment for that would be 29877—debridement/shaving of articular cartilage (chondroplasty). However, the national correct coding initiative (CCI) bundles code 29877 into 29881 for Medicare claims and some other third-party payers follow that practice too. Assign modifier -LT, Left Side, to the facility CPT code.

The correct code for the professional component will remain 29881. This is also the correct code for the facility assignment but you will need to add modifier LT to identify that the procedure was performed on the left side of the body (29881-LT).

Peggy Hapner is manager of the HIM consulting division at Medical Learning Inc. (MedLearn®), St. Paul, MN.

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