Orthopedic coding knee procedures requires knowledge of knee anatomy. The knee joint is the largest and most complex joint of the body. It is a modiﬁed hinge joint that consists of three joints within a single synovial cavity:
- Laterally is a tibiofemoral joint, between the lateral condyle of the femur, lateral meniscus, and lateral condyle of the tibia, which is weight-bearing (Lateral Compartment)
- Medially is a second tibiofemoral joint, between the medial condyle of the femur, medial meniscus, and medial condyle of the tibia (Medial Compartment)
- An intermediate patellofemoral joint is between the patella and the patellar surface of the femur (Patellofemoral Compartment)
Articular cartilage is the soft, elastic cartilage that covers the ends of bones within the joint. In the knee, articular cartilage covers the lower end of the femur, the upper end of the tibia, and the undersurface of the patella.
Synovium (Synovial membrane) is the delicate, thin membrane that encapsulates the knee joint. The synovial membrane produces synovial fluid which lubricates the joint to reduce friction on the articular cartilage during motion.
Limited Vs Major Synovectomy
Arthroscopic synovectomy of the knee may be reported with CPT codes 29875 (Limited synovectomy, “separate procedure”) or 29876 (Major synovectomy of two or three compartments). Below are the CPT code descriptions for arthroscopic synovectomy procedures.
cpt code 29875: Arthroscopy, knee, surgical; synovectomy, limited (eg, plica or shelf resection) (separate procedure)
cpt code 29876: Arthroscopy, knee, surgical; synovectomy, major, 2 or more compartments (eg, medial or lateral)
A synovectomy to “clean up” a joint on which another more extensive procedure is performed is not separately reportable. CPT code 29875 should not be reported with another arthroscopic knee procedure on the ipsilateral knee. CPT code 29876 may be reported for a medically reasonable and necessary synovectomy with another arthroscopic knee procedure on the ipsilateral knee if the synovectomy is performed in 2 compartments on which another arthroscopic procedure is not performed.
For example, CPT code 29876 shall not be reported for a major synovectomy with CPT code 29880 (Knee arthroscopy, medial AND lateral meniscectomy) on the ipsilateral knee, since knee arthroscopic procedures other than synovectomy are performed in 2 of the 3 knee compartments.
Debridement of Articular Cartilage vs Synovium
Arthroscopic debridement of articular cartilage should be reported with CPT code 29877, whereas debridement of synovium should be reported with CPT code 29875 or 29876. Surgical debridement of the synovial tissue is a synovectomy.
A 65-year-old male presents with right knee pain. His conservative management failed, so he decided to go with surgical options. He was diagnosed with right knee synovitis. An arthroscopic debridement of the right knee synovitis was done in the medial compartment of the knee.
A 62-year-old female presents with left knee pain and swelling. His conservative management failed, so he decided to go with surgical options. She was diagnosed with left knee synovitis. An arthroscopic debridement of the left knee synovitis was done in the medial and lateral compartments.
A 55-year-old male presents with chronic left knee pain. His conservative management failed, so he decided to go with surgical options. He was diagnosed with left knee primary osteoarthritis. An arthroscopic debridement of articular cartilage was done in both the medial and lateral compartment of the left knee.
- CPT Assistant, August 2021
- NCCI Policy Manual for Medicare 2021: Chapter 4