Orthopedic Coding Alert

Pay attention to the laterality of this condition.

Chondromalacia patellae (CMP) is pain at the front of the knee due to an irritation of the undersurface of the kneecap. Often occurring in young, healthy athletes, the kneecap rubs against one side of the knee joint and the cartilage surface becomes irritated. Thus, the patient presents with knee pain.

Right now, you should report this code with 717.7 (Chrondromalacia of patella). However, that changes in 2014. You will report CMP with this:

• M22.40, Chondromalacia patellae, unspecified knee
• M22.41, Chondromalacia patella, right knee
• M22.42, Chondromalacia patellae, left knee

ICD-10-CM Change: Your single ICD-9-CM chondromalacia patellae code (717.7) expands into three options (M22.40-M22.41) based on whether the condition occurs on the right or left side. You do have an unspecified option, but you should always code to the highest level of specificity.

Documentation: Your provider probably already documents whether the condition occurred on the right or left knee, and in ICD-10-CM, you have a way to reflect that.

Here is how you will locate these codes in the Alphabetic Index:

Chondromalacia (systemic) M94.20

- knee M94.26-

- - patella M22.4-

- patella M22.4-

Softening

- cartilage M94.2-

- - patella M22.4-

Coder tips: Underneath the M22 category, you will find an Excludes1 note that prevents you from reporting any of these codes with traumatic dislocation of the patellae (S83.0-).

Note: Similar code 733.92 (Chondromalacia), which you report for all sites other than the patella, expands into 24 options (M942--, Chondromalacia …) based on anatomical site.