Revenue Cycle Insider

Question: My ortho doctor sees many patients with osteoarthritis (OA), especially in the hip and knee. I want to make sure we’re coding the diagnosis correctly. How do I determine which type of osteoarthritis to code, and what are the key steps to select the right ICD-10-CM code, including laterality and any additional diagnoses needed?

South Carolina Subscriber

Answer: OA can be tricky to code because there are several types and specific codes depending on the joint affected and the details in the provider’s notes. First, understand that OA isn’t one-size-fits-all. There are different types, such as polyosteoarthritis (multiple joints affected), primary osteoarthritis (wear and tear), secondary osteoarthritis (caused by another condition), post-traumatic osteoarthritis (following an injury), dysplastic osteoarthritis (related to hip alignment issues), and other types when the exact OA doesn’t fit specific codes.

To code OA correctly, follow these steps:

1. Identify the joint or location affected (for example, hip or knee). This is essential because ICD-10-CM has detailed codes by site.
2. Determine the type of OA. Is it primary, secondary, post-traumatic, dysplastic, or polyosteoarthritis? The provider’s documentation should state this or give enough detail to determine it.
3. Note the laterality — whether the OA affects the right side, left side, or both sides (bilateral). ICD-10-CM codes for hip and knee OA often require this 5^th character to specify laterality.
4. Select the appropriate code based on the above details. For example, if a patient has post-traumatic OA in the right knee, you would report M17.31 (Unilateral post-traumatic osteoarthritis, right knee).

If the OA is secondary, you must also code the underlying cause, such as a prior injury, or another condition contributing to the OA.

Always check the ICD-10-CM guidelines for any required 5^th characters or additional documentation needed to support your coding. This careful approach ensures accurate and compliant OA diagnosis coding, which is especially important in orthopedics, where these cases are common.

Suzanne Burmeister, BA, MPhil, Medical Writer and Editor