R412 – Arthrotomy of knee
OHIP Radiology Code — MUSCULOSKELETAL SYSTEM SURGICAL PROCEDURES · Schedule of Benefits
Performs an arthrotomy of the knee. The description 'with or without removal of loose body' indicates that removing a loose body is an optional but included component of the procedure and is not billed separately, as per the rules on . As a surgical procedure listed in the Musculoskeletal System section, it is eligible for payment for the surgeon (<suffix>A</suffix>), surgical assistant (<suffix>B</suffix>), and anaesthetist (<suffix>C</suffix>). The base units for the assistant are 6 and for the anaesthetist are 7, as specified on . Various premiums may apply, including those for after-hours services, specific patient age groups (), and major trauma cases (E420 on ).
When to Use
- Use R412 for an open arthrotomy of the knee performed to access the joint space for diagnostic or therapeutic purposes, such as irrigation or debridement.
- Use R412 when removing a loose body from the knee joint via open arthrotomy, as this is explicitly included in the code description and cannot be billed as an additional procedure.
Common Pitfalls
- Do not bill R412 in conjunction with arthroscopic procedures (e.g., R415), as the Schedule of Benefits generally prohibits billing an open procedure and an arthroscopic procedure on the same joint during the same operative session.
- Do not attempt to bill for the removal of a loose body as a separate procedure; the R412 fee is comprehensive for the arthrotomy regardless of whether a loose body is found or removed.
Billing Tips
- Ensure the operative report clearly details the open nature of the arthrotomy to distinguish it from arthroscopic codes, which are often subject to different fee structures and clinical requirements.
- If the procedure is performed as part of a major trauma case, ensure the Injury Severity Score (ISS) is documented in the medical record to support the application of the E420 trauma premium.
Effective: April 1, 2025
N. Musculoskeletal System Surgical Procedures
MUSCULOSKELETAL SYSTEM SURGICAL PROCEDURES
Surgical
Musculoskeletal System Surgical Procedures
Knee - with or without removal of loose body
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