Billing code 27446: Partial knee replacementMedicare rate & RVUs in Washington
Reports knee replacement limited to the medial or lateral compartment, such as for isolated compartment disease treated with a partial prosthesis.
CMS doesn’t publish an office rate for 27446 in Washington.
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 27446 covers
An orthopedic surgeon uses this code for a knee arthroplasty confined to one femorotibial compartment: medial or lateral. A typical case is replacement of the damaged surfaces in one compartment for isolated disease, rather than replacement of the entire knee. The operative report should identify the compartment treated and describe the prosthetic reconstruction. This code is used for partial knee replacement, not a revision merely because the CMS short descriptor uses broad revision wording.
Choose the code by the extent of the arthroplasty documented, not by disease severity or the number of implant pieces. Distinguish a one-compartment procedure from arthroplasty involving both compartments or total knee replacement. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures occur in the same session, the highest-valued procedure is paid in full and others at 50%. For bilateral procedures reported with modifier 50, CMS pays at 150%. Assistant-at-surgery payment may be made; co-surgeon payment requires 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 27446 pays more and less in Washington
| Payment locality | Office | Facility |
|---|---|---|
| Rest Of Washington | Unavailable | $1,046.23 |
| Seattle (King Cnty) | Unavailable | $1,138.15 |
How the 27446 rate is calculated
Each of 27446’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 · 27446
RVUs × geographic indexes × conversion factor
Swap in your local Medicare rate.
Work 16.70Practice expense 11.13Malpractice 3.53
All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.
Payment rules and modifiers for 27446
27446 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 27446
Partial knee replacement
| 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 · 27446
Partial knee replacement
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
27446 without 50 · national facility
$1,047.45
Partial knee replacement
27446-50 · Bilateral: 150%
$1,571.18
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).
27446 compared with similar codes
Compare codes
27446 vs 27442 vs 27447 vs 27486: national Medicare rates
Swap in your local Medicare rate.
How to choose
- 27442Knee revision
- 27442 describes arthroplasty involving both medial and lateral compartments; 27446 is limited to either one.
- 27447Total knee replacement
- 27447 is used for total knee arthroplasty. Use 27446 when the operative work is confined to one compartment.
- 27486Knee revision
- 27486 describes revision knee arthroplasty involving one component. It is a revision procedure, unlike the one-compartment arthroplasty reported with 27446.
27446 billing questions
How is 27446 distinguished from total knee replacement?
Use 27446 when the arthroplasty is confined to the medial or lateral compartment. Total knee arthroplasty is reported when the operative procedure replaces the knee more extensively.
What documentation supports 27446?
The operative report should identify the medial or lateral compartment treated and document the arthroplasty performed there. It should make clear that the procedure was limited to one compartment.
How is bilateral 27446 paid?
CMS pays bilateral procedures reported with modifier 50 at 150%.
What postoperative care is included?
The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care.
Can an assistant or co-surgeon be reported?
Assistant-at-surgery payment may be made. Co-surgeon payment requires supporting documentation; CMS does not permit team surgery.
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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