CPT code 27437: Patellar arthroplasty, without prosthesis2026 Medicare rate & RVUs in Maine
Reports surgical reshaping or reconstruction of the patella without a prosthetic implant when the operative treatment is limited to the kneecap.
CMS doesn’t publish an office rate for 27437 in Maine.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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What 27437 covers
An orthopedic surgeon performs this operation to reshape or reconstruct the kneecap’s joint surface without placing a prosthesis. It is used for selected patellar conditions where the operative plan addresses the patella itself, rather than replacing the patellar surface with an implant. The procedure is generally performed in a hospital or ambulatory surgery setting. The operative report should identify the patellar condition, describe the work performed on the patella, and make clear that no prosthetic patellar component was implanted.
Select this code based on the documented procedure, not simply a diagnosis of patellar pain or cartilage disease. Distinguish it from patellar arthroplasty with a prosthesis and from procedures directed at recurrent patellar dislocation or broader knee replacement. Medicare assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and the others at 50%. Bilateral reporting with modifier 50 is paid at 150%. Assistant-at-surgery payment is restricted; co-surgeons are paid only with 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 27437 pays more and less in Maine
| Payment locality | Office | Facility |
|---|---|---|
| Rest of Maine | Unavailable | $579.90 |
| Southern Maine, ME | Unavailable | $599.80 |
How the 27437 rate is calculated
Each of 27437’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 · 27437
RVUs × geographic indexes × conversion factor
Work8.71
8.71 RVUs× 1.000 GPCI
Practice expense8.16
8.16 RVUs× 1.000 GPCI
Malpractice1.84
1.84 RVUs× 1.000 GPCI
Adjusted RVUs
18.7100
Conversion factor
$33.4009
Medicare rate
$624.93
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 27437
27437 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 27437
Patellar arthroplasty, without prosthesis
| 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) | 1 | Not paid (statutory restriction). |
| 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 · 27437
Patellar arthroplasty, without prosthesis
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
27437 without 50 · national facility
$624.93
Patellar arthroplasty, without prosthesis
27437-50 · Bilateral: 150%
$937.39
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).
27437 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 27438Patellar arthroplastyWith prosthesis
- Both codes address patellar arthroplasty; 27437 is for treatment without a prosthetic component, while 27438 includes one.
- 27420Patellar reconstructionWithout extensor realignment
- Use 27420 for patellar reconstruction directed at recurrent dislocation, not arthroplasty of the patellar surface.
- 27422Patellar reconstructionWith extensor realignment
- This code is for patellar reconstruction with extensor realignment and/or muscle advancement for instability; 27437 addresses patellar arthroplasty without a prosthesis.
- 27447Total knee replacementMedial and lateral compartments
- Code 27447 describes total knee arthroplasty. It represents replacement of the knee joint, not an isolated patellar arthroplasty without a prosthesis.
27437 billing questions
How does this differ from 27438?
Code 27437 describes patellar arthroplasty without a prosthesis. Use 27438 when the patellar arthroplasty includes a prosthetic implant.
Is this the code for recurrent patellar dislocation?
Not when the operation is directed at stabilizing a dislocating patella. Codes 27420 and 27422 describe patellar reconstruction procedures for that operative goal.
What documentation supports reporting 27437?
The operative report should identify the patella as the treated structure, describe the arthroplasty work, and establish that no patellar prosthesis was implanted.
Can modifier 50 be used when both patellae are treated?
Yes. CMS identifies this as a bilateral procedure; bilateral reporting with modifier 50 is paid 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.
How are assistant and co-surgeon services handled?
Assistant-at-surgery payment is restricted. Co-surgeons are paid only with supporting documentation, and team surgery is not permitted.
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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