Fasciotomy of multiple compartments of the thigh and/or knee with debridement of necrotic or devitalized tissue to relieve pathologically elevated compartment pressure.

Verified May 8, 2026 · 5 sources ↓

Medicare: $663.68
Work RVU: 9.19
Global, days: 90
Region: Knee

Drawn from CMSAAPCAAOSAAHKS

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 5 cited references ↓

Identify each fascial compartment of the thigh and/or knee that was incised — generic 'multiple compartments' without naming them invites downcoding or denial.
Document the clinical basis for decompression: compartment pressure measurements, pulse exam findings, mechanism of injury, or time-sensitive ischemic signs.
Describe debridement specifically: tissue type removed (muscle, fascia, subcutaneous), estimated volume or surface area, and viability assessment.
Record wound management at case end — primary closure, delayed primary closure, negative-pressure wound therapy, or open packing — as this affects postoperative coding during the global period.
Include operative photos or intraoperative findings notes that confirm the extent of fascial release, particularly when modifier 22 is appended for significantly increased work.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 24 Unrelated E/M during global 51 Multiple procedures 58 Staged or related 59 Distinct service 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side XS Separate structure

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 27499 covers decompression fasciotomy involving multiple compartments of the thigh and/or knee, performed to relieve acute or chronic elevated compartment pressure. The surgeon incises the fascia of two or more compartments and removes necrotic or damaged tissue. It sits at the top of the thigh fasciotomy ladder: 27496–27497 cover single-compartment thigh fasciotomy, while 27498–27499 address multiple compartments. Calf compartment releases are coded separately (27892–27894) and should not be bundled with 27499 when both regions are addressed.

The 90-day global period means all routine follow-up — wound checks, suture removal, and staged wound closure visits — is bundled into the payment. If a separate, unrelated E/M is warranted during the global window, append modifier 24. A return to the OR for a related complication (e.g., re-exploration for persistent ischemia) uses modifier 78; an unrelated procedure in the same global period uses modifier 79. Document the specific compartments released and the extent of debridement — 'fasciotomy performed' without anatomic specificity is a recurring audit flag for this code family.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (9.19) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (19.87) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	9.19
Practice expense RVU	8.72
Malpractice RVU	1.96
Total RVU	19.87
Medicare national rate	$663.68
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$663.68
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI A2) Ambulatory surgical center (freestanding)	$3,695.53

Common denial reasons

The recurring reasons claims for CPT 27499 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Operative note lacks named compartments released — payers cannot confirm multiple-compartment criteria are met and downcode to the single-compartment code.
Missing or inadequate compartment syndrome diagnosis linkage — ICD-10 traumatic or nontraumatic compartment syndrome codes must appear on the claim and align with the operative documentation.
Bundling conflict when calf fasciotomy codes (27892–27894) are billed same-day without a distinct anatomic-region modifier or modifier 59/XS to support separate anatomic work.
Global period violations — postoperative wound checks or irrigation/debridement visits billed without modifier 24 or 78 during the 90-day window.
Site-of-service mismatch between the place-of-service code on the claim and the documented setting, especially when emergency department fasciotomy transitions to inpatient care.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What distinguishes 27499 from 27497?

27496–27497 cover single-compartment thigh fasciotomy; 27498–27499 are used when two or more compartments are released. The operative note must name each compartment opened to support the higher-level code.

02Can I bill 27499 and a calf fasciotomy code on the same day?

Yes — the thigh/knee and calf are anatomically distinct regions. Bill the appropriate leg fasciotomy code (27892–27894) alongside 27499. Append modifier 51 to the secondary procedure and consider modifier 59 or XS to clarify distinct anatomic sites if a bundling edit fires.

03How do I handle a staged return for wound closure during the 90-day global?

A planned staged closure (e.g., split-thickness skin graft or delayed primary closure) within the global period uses modifier 58, indicating a staged or related procedure. Do not use modifier 78 here — that modifier is for unplanned returns for complications.

04When is modifier 22 appropriate for 27499?

Append modifier 22 when the work substantially exceeds the typical decompression — for example, extensive multilevel necrosis requiring protracted debridement, or a massively swollen thigh requiring a significantly longer and more complex fasciotomy. Support it with a separate operative note paragraph quantifying the added time and complexity.

05What ICD-10 codes typically pair with 27499?

Traumatic compartment syndrome of the thigh (ICD-10 T79.A21/T79.A22) and nontraumatic compartment syndrome codes (M79.A21/M79.A22) are the primary diagnoses. The specific laterality code should match the LT or RT modifier on the claim.

06Is 27499 typically performed in an ASC setting?

Acute compartment syndrome fasciotomy is usually done in a hospital OR given the emergent nature and need for postoperative monitoring. The HOPD and ASC payment rates differ substantially — see the Site of Service comparison on this page. Many payers and facility policies require inpatient admission for thigh decompression, making the ASC rate an uncommon scenario in practice.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira Scribe

Mira's AI scribe captures the named compartments released (e.g., anterior, posterior, medial, lateral), the surgeon's compartment pressure values or clinical criteria prompting decompression, tissue viability findings at debridement, and wound closure method — all in the operative note. That detail prevents the most common denial: a note that says 'fasciotomy performed' without the compartment-level specificity required to defend 27499 over its single-compartment sibling codes.

See how Mira captures CPT 27499 documentation