Background: The knee joint is the largest joint in the body. Anatomists and orthopedists usually describe it as having three compartments. A common term in an orthopedist's chart is a patient described as having "tri-compartmental osteoarthritis," meaning that all three compartments are involved with arthritic change.
Separate-Compartment Procedures Can Be Paid The compartments are important for coding because the National Correct Coding Initiative bundles procedures that surgeons perform in the same compartment. For example, if one performs a medial meniscectomy and a concurrent synovectomy on the medial side of the knee, the surgeon may only charge one code in this situation, because both structures are in the same compartment.
The three compartments are the medial compartment, the lateral compartment, and the patello-femoral compartment. The medial and lateral compartments are described more accurately as the medial femoral-tibial compartment and the lateral femoral-tibial compartment.
The knee includes another anatomic region, termed the intra-articular notch. This is the open posterior area of the femur between the medial and lateral femoral condyles. It is an oft-operated region, because it contains the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), but it is really not considered a "compartment" for coding purposes. Know Anatomic Terms to Select Code Op Report Tip: If you see any of the following terms in your surgeon's operative note, you'll know that the procedure occurred in the medial compartment:
Medial meniscus - anterior and posterior horns
Medial femoral condyle
Medial tibial plateau
Medial ligamentous structures - medial collateral ligament (internally). Look for the following terms to indicate that the surgeon addressed the lateral compartment:
Lateral meniscus - anterior and posterior horns
Lateral femoral condyle
Lateral tibial plateau
Lateral ligamentous structures - lateral collateral ligament (internally) and the popliteus tendon. You can rest assured that the surgeon addressed the patello-femoral compartment if he documents the following:
Surgery in the deep surface of the patella or the superficial surface of the anterior femur, usually termed the "trochlear groove." Be on the lookout: A fibrous structure, termed a "plica," may be found in the knee and is most often located in the patello-femoral compartment, although it could be in any compartment. If you're unsure of the location of the plica that your surgeon documents, ask the physician specifically which compartment he addressed.
1 Compartment Leads to 1 Code Payers usually [...]