CPT code 27331: Knee arthrotomy2026 Medicare rate & RVUs in Delaware

Reports open knee surgery to remove synovial tissue from an anterior or posterior portion of the joint when direct surgical treatment is performed.

CMS RVU26DEffective Oct 1, 2026One payment locality599 Medicare services in 2024

In Delaware, Medicare pays $453.76 for 27331 in a facility. There’s no office rate.

Not available in this settingOffice (non-facility)
$453.76Hospital or facility

Check a contract rate as a % of Medicare · 27331 nationwide

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

We’ll open 27331 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in Delaware
  2. What 27331 covers
  3. Compared with other areas
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Related codes
  8. Rate history
  9. Where it applies
  10. Billing questions
  11. Sources

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.

How Delaware compares for 27331

Across 109 of 109 payment localities, the facility rate for 27331 runs from $408.31 in Arkansas to $560.42 in San Jose-Sunnyvale-Santa Clara (San Benito Cnty). Delaware pays $453.76. The RVUs are the same everywhere; the geographic indexes change the dollars.

27331 in Delaware vs other payment areas
  1. Delaware · this page$453.76
  2. Dc + Md/Va Suburbs · District of Columbia$514.42+$60.66
  3. Miami · Florida$531.53+$77.77
  4. Chicago · Illinois$515.28+$61.52
  5. Manhattan · New York$532.26+$78.50
  6. Alaska* · Alaska$553.64+$99.88

Other areas in Delaware first, then benchmark localities. Bars start at $0.

Every other payment area

27331 in every other Medicare payment locality
Payment localityOfficeFacility
AlabamaAlabama—$413.96
ArkansasArkansas—$408.31
ArizonaArizona—$446.78
BakersfieldCalifornia—$468.61
ChicoCalifornia—$465.22
El CentroCalifornia—$465.43
FresnoCalifornia—$465.22
Hanford-CorcoranCalifornia—$465.22

27331 rates by state

Office rate range in each state. Select a state to see its payment localities.

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Local rates. Clear comparisons.

Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.

View every state and territory as a table
27331 office rate range by state
State / territoryOffice rate rangeLocalities
AKNo published base rate1
ALNo published base rate1
ARNo published base rate1
AZNo published base rate1
CANo published base rate29
CONo published base rate1
CTNo published base rate1
DCNo published base rate1
DENo published base rate1
FLNo published base rate3
GANo published base rate2
GUNo published base rate1
HINo published base rate1
IANo published base rate1
IDNo published base rate1
ILNo published base rate4
INNo published base rate1
KSNo published base rate1
KYNo published base rate1
LANo published base rate2
MANo published base rate2
MDNo published base rate3
MENo published base rate2
MINo published base rate2
MNNo published base rate1
MONo published base rate3
MSNo published base rate1
MTNo published base rate1
NCNo published base rate1
NDNo published base rate1
NENo published base rate1
NHNo published base rate1
NJNo published base rate2
NMNo published base rate1
NVNo published base rate1
NYNo published base rate5
OHNo published base rate1
OKNo published base rate1
ORNo published base rate2
PANo published base rate2
PRNo published base rate1
RINo published base rate1
SCNo published base rate1
SDNo published base rate1
TNNo published base rate1
TXNo published base rate8
UTNo published base rate1
VANo published base rate2
VINo published base rate1
VTNo published base rate1
WANo published base rate2
WINo published base rate1
WVNo published base rate1
WYNo published base rate1

See 27331 in every payment locality

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

Work5.87

5.87 RVUs× 1.000 GPCI

Practice expense6.66

6.66 RVUs× 1.000 GPCI

Malpractice1.23

1.23 RVUs× 1.000 GPCI

Adjusted RVUs

13.7600

Conversion factor

$33.4009

Medicare rate

$459.60

Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.

The exact Delaware inputs and CMS source lines

PPRRVU2026_Oct_nonQPP.csv

2,842

Code
27331
Physician work
5.87
Practice expense
6.66
Malpractice
1.23

GPCI2026.csv

40

Locality
Delaware
Physician work
1.005
Practice expense
0.988
Malpractice
0.899
Facility calculation for 27331 in Delaware
ComponentRVULocality factorAdjusted
Physician work5.87× 1.0055.8993
Practice expense6.66× 0.9886.5801
Malpractice1.23× 0.8991.1058
Total RVUs13.5852
Conversion factor× 33.4009

Facility rate, Delaware$453.76

Facility: (5.87 × 1.005 + 6.66 × 0.988 + 1.23 × 0.899) × $33.4009 = $453.76

Open 27331 in the RVU calculator

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

RuleCMS valueWhat it means
Global period090Major surgery: the day before, the day of, and 90 days after are included.
Multiple procedures2Standard reduction: highest-valued procedure at 100%, others at 50%.
Bilateral (modifier 50)1Bilateral with modifier 50 pays 150% of the fee schedule amount.
Assistant at surgery (80/81/82/AS)2Paid.
Co-surgeons (62)1Permitted with supporting documentation.
Team surgery (66)0Not permitted.
Professional/technical0Physician service: no professional/technical split.
Split (54/55/56)0.10/0.69/0.21Share 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.

  • 24Unrelated E/M visit by the same physician
  • 79Unrelated procedure (starts its own global period)
  • 58Staged, more extensive, or therapy procedure that was planned
  • 78Unplanned return to the operating room for a related complication
SurgeryVisit
Sep 23, 2026Jan 10, 2027

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).

When to use modifier 50

How 27331 has changed in Delaware

27331 · Office / nonfacility

Rate unavailable

Effective 2026-10-01

A rate is unavailable in one of these releases, so a change cannot be calculated.

Base rate by release · bars start at $0 · select a bar to compare

One bar per available release, ordered by effective date. Missing rates remain gaps. These comparisons hold the code, setting and locality identifiers constant; they do not isolate which policy or input caused a change.

What changed, release by release
Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01Not available in this setting$453.76RVU26D
2026-07-01Not available in this setting$453.76RVU26C
2026-04-01Not available in this setting$453.76RVU26B
2026-01-01Not available in this setting$453.76RVU26A
2025-10-01Not available in this setting$475.86RVU25D
2025-07-01Not available in this setting$475.86RVU25C
2025-04-01Not available in this setting$475.86RVU25B
2025-01-01Not available in this setting$475.86RVU25A
2024-10-01Not available in this setting$484.09RVU24D
2024-07-01Not available in this setting$484.09RVU24C
2024-04-01Not available in this setting$484.09RVU24B
2024-03-09Not available in this setting$484.09RVU24AR
2024-01-01Not available in this setting$476.18RVU24A
2023-10-01Not available in this setting$490.63RVU23D
2023-07-01Not available in this setting$490.63RVU23C
2023-04-01Not available in this setting$490.63RVU23B
2023-01-01Not available in this setting$490.63RVU23A
2022-10-01Not available in this setting$495.41RVU22D
2022-07-01Not available in this setting$495.41RVU22C
2022-04-01Not available in this setting$495.41RVU22B
2022-01-01Not available in this setting$495.41RVU22A
2021-10-01Not available in this setting$495.66RVU21D
2021-07-01Not available in this setting$495.66RVU21C
2021-04-01Not available in this setting$495.66RVU21B
2021-01-01Not available in this setting$495.66RVU21A
2020-10-01Not available in this setting$500.90RVU20D
2020-07-01Not available in this setting$500.90RVU20C
2020-04-01Not available in this setting$500.90RVU20B
2020-01-01Not available in this setting$500.90RVU20A
2019-10-01Not available in this setting$503.33RVU19D
2019-07-01Not available in this setting$503.33RVU19C
2019-04-01Not available in this setting$503.33RVU19B
2019-01-01Not available in this setting$503.33RVU19A
2018-10-01Not available in this setting$501.24RVU18D
2018-07-01Not available in this setting$501.24RVU18C
2018-04-01Not available in this setting$501.24RVU18B
2018-01-01Not available in this setting$501.24RVU18AR1
2017-10-01Not available in this setting$500.66RVU17D
2017-07-01Not available in this setting$500.66RVU17C
2017-04-01Not available in this setting$500.66RVU17B
2017-01-01Not available in this setting$500.66RVU17A
2016-10-01Not available in this setting$500.91RVU16D
2016-07-01Not available in this setting$500.91RVU16C
2016-04-01Not available in this setting$500.91RVU16B
2016-01-01Not available in this setting$500.91RVU16A
2015-10-01Not available in this setting$504.61RVU15D
2015-07-01Not available in this setting$504.61RVU15C
2015-04-01Not available in this setting$502.10RVU15B
2015-01-01Not available in this setting$502.10RVU15A
2014-10-01Not available in this setting$491.02RVU14D
2014-07-01Not available in this setting$491.02RVU14C
2014-04-01Not available in this setting$491.02RVU14B
2014-01-01Not available in this setting$491.02RVU14A
2013-10-01Not available in this setting$482.90RVU13D
2013-07-01Not available in this setting$482.90RVU13C
2013-04-01Not available in this setting$482.90RVU13B
2013-01-01Not available in this setting$482.90RVU13AR

Price 27331 for an earlier date of service

Where the Delaware rate applies

Delaware is a Medicare payment area, not a city. Our Census mapping connects it to 79 cities and communities in Delaware. Some span more than one payment area; confirm with the service ZIP.

Browse all communities in Delaware

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
RVUs for 27331PPRRVU2026_Oct_nonQPP.csv, line 2,842 (RVU26D)
Geographic factors for DelawareGPCI2026.csv, line 40 (RVU26D)

Open CMS sourceHow we calculate rates

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