Arthroscopy converted to open not documented (Updated for 2026)

Common Causes for O20

Denials with code O20 typically happen for the following specific reasons:

• The operative report fails to provide a detailed, sequential narrative explaining the transition from the arthroscopic approach to the open surgical approach.
• Both the arthroscopic and open procedure codes were billed simultaneously for the same anatomic site without documentation supporting distinct, separately reportable services.
• The medical documentation lacks clear clinical justification or specific findings during the arthroscopy that necessitated the conversion to an open technique.
• Failure to submit the comprehensive operative report along with the claim when utilizing modifiers or codes that represent a converted surgical session.

How to Prevent O20 Denials

To avoid receiving this denial in the future, implement these specific checks:

• Ensure providers document a detailed 'Description of Procedure' that explicitly outlines the initial arthroscopic attempt, the specific findings, the clinical decision to convert, and the subsequent open procedure.
• Adhere strictly to CMS and AMA CPT guidelines stating that when an arthroscopy is converted to an open procedure, only the open procedure code should be billed unless a separate diagnostic arthroscopy was fully completed and documented.
• Implement pre-claim review processes to verify that operative notes are attached to any claims involving surgical conversions to prevent immediate documentation-related denials.
• Provide regular clinical documentation improvement training to orthopedic and general surgeons on the necessity of documenting conversion details, including timestamps and anatomical landmarks examined.

Appeal Letter Template for O20

If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.

[Your Practice Header]
[Date]

[Payer Name]
[Appeals Department Address]

RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: O20 - Arthroscopy converted to open not documented

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code O20: "Arthroscopy converted to open not documented".

We are appealing the denial for the converted procedure, as the clinical documentation fully supports the necessity and separate nature of the services billed. Pursuant to the AMA CPT guidelines and the CMS National Correct Coding Initiative (NCCI) Policy Manual, when a diagnostic arthroscopy is completed and leads to the clinical decision to perform an open procedure, both may be reportable if they represent distinct, non-overlapping services. As detailed in the attached operative report, the physician performed a complete diagnostic arthroscopic evaluation, identified specific pathology that could not be safely or effectively addressed arthroscopically, and subsequently converted to an open approach to complete the therapeutic procedure. Because the documentation clearly delineates the separate diagnostic phase from the open surgical phase, we respectfully request that the denial be overturned and the claim be processed for full payment.

Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].

We respectfully request that you reprocess this claim for payment.

Sincerely,

[Your Name]
[Title]
[Practice Name]