Billing code 27331: Knee arthrotomyMedicare rate & RVUs in Virginia
Reports open knee surgery to remove synovial tissue from an anterior or posterior portion of the joint when direct surgical treatment is performed.
CMS doesn’t publish an office rate for 27331 in Virginia.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 27331 covers
Code 27331 represents open entry into the knee joint to remove synovial tissue from either its anterior or posterior portion. Orthopedic surgeons may perform it for symptomatic synovial disease requiring direct surgical treatment. The operative report should establish the open approach and identify the portion of the joint treated. The procedure is typically performed in an operating room, including hospital outpatient and inpatient settings.
Select this code when the documented work is an anterior or posterior synovectomy, rather than a biopsy alone or a major synovectomy involving multiple compartments. Documentation should describe the synovial abnormality, surgical approach, area treated, and extent of tissue removal. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. In a same-session multiple-procedure claim, the highest-valued procedure is paid in full and other procedures at 50%. Bilateral procedures with modifier 50 are paid at 150%. Assistant-at-surgery payment may be made; co-surgeons require supporting documentation, and team surgery is not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 27331 pays more and less in Virginia
| Payment locality | Office | Facility |
|---|---|---|
| Dc + Md/Va Suburbs | Unavailable | $514.42 |
| Virginia | Unavailable | $443.74 |
How the 27331 rate is calculated
Each of 27331’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 27331
RVUs × geographic indexes × conversion factor
Swap in your local Medicare rate.
Work 5.87Practice expense 6.66Malpractice 1.23
All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.
Payment rules and modifiers for 27331
27331 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 27331
Knee arthrotomy
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.10/0.69/0.21 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 27331
Knee arthrotomy
90-day global period ends
Dec 30, 2026
Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).
Visit on Oct 31, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 50 · payment effect
With and without the modifier
27331 without 50 · national facility
$459.60
Knee arthrotomy
27331-50 · Bilateral: 150%
$689.40
Both sides on one line with modifier 50 are paid at 150% of the fee schedule amount (subject to multiple-procedure rules with other procedures).
27331 compared with similar codes
Compare codes
27331 vs 27330 vs 27334 vs 27335: national Medicare rates
Swap in your local Medicare rate.
How to choose
- 27330Knee biopsy
- Choose 27330 when the arthrotomy is performed to obtain a biopsy. Choose 27331 when the operative work removes synovial tissue from an anterior or posterior portion of the joint.
- 27334Knee synovectomy
- 27334 describes a major synovectomy involving two compartments. Distinguish it from 27331 by the documented extent and compartments treated.
- 27335Knee synovectomy
- 27335 describes a major synovectomy involving three compartments; 27331 describes an anterior or posterior synovectomy.
27331 billing questions
How is 27331 different from 27330?
Use 27331 for open removal of synovial tissue from an anterior or posterior portion of the knee joint. Code 27330 is for an arthrotomy performed to obtain a biopsy.
When should a major synovectomy code be considered instead?
Compare the documented extent with 27334 and 27335, which describe major synovectomy involving two or three knee compartments. Code 27331 distinguishes an anterior or posterior synovectomy.
How does Medicare handle bilateral reporting?
For a bilateral procedure reported with modifier 50, CMS pays 150%.
What postoperative care is included in the global period?
The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care.
What should the operative report support?
Document the open approach, the synovial abnormality, whether the anterior or posterior portion was treated, and the extent of tissue removal.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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