Soft tissue repair · Foot & ankle

20973

Free osteocutaneous flap harvested from the great toe with web space, transferred to a recipient site using microvascular anastomosis to restore both bone and soft tissue.

Verified May 8, 2026 · 7 sources ↓

Medicare
$2,670.40
Total RVUs
79.95
Global, days
90
Region
Foot & ankle
Drawn from CMSAAPCNIHEmednyAAOS

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

  • Operative note must name the donor site explicitly as great toe with web space
  • Document the recipient site anatomy, defect size, and indication (trauma, tumor, infection, etc.)
  • Microvascular anastomosis technique must be described — artery and vein identified, anastomosis method, and patency confirmation
  • Specify tissue components harvested: bone dimensions, skin paddle dimensions, and vascular pedicle
  • Document intraoperative flap perfusion assessment (e.g., Doppler signal, capillary refill, color)
  • Pre-operative imaging or angiography supporting vascular anatomy planning should be referenced

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 52 Reduced services 58 Staged or related 59 Distinct service 62 Co-surgeons 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 7 cited references ↓

CPT 20973 describes harvesting a free osteocutaneous flap from the great toe with its web space — bone, overlying skin, and intact vascular pedicle — and transferring it to a distant recipient site via microvascular anastomosis. The procedure reconstructs composite defects where both skeletal continuity and soft tissue coverage are lost, typically from trauma, tumor resection, or infection. The microvascular component requires precise arterial and venous anastomoses under magnification, making this one of the most technically demanding procedures in the musculoskeletal CPT range.

The 90-day global period covers all routine postoperative care through day 90, including flap monitoring visits, dressing changes, and suture removal. Any new problem or unrelated procedure billed during that window requires modifier 24 or 79, respectively. Return to the OR for flap-related complications — such as vascular compromise requiring re-exploration — bills under modifier 78.

CMS has designated 20973 as an inpatient-only procedure under the OPPS (status indicator C). It cannot be billed in an ASC or hospital outpatient setting for Medicare patients. The procedure is most commonly performed by plastic surgeons, hand surgeons, or orthopedic microsurgeons, and often appears in the context of toe-to-hand transfer cases where related codes 26551, 26553, 26554, or 26556 may also be relevant.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU46.09
Practice expense RVU24
Malpractice RVU9.86
Total RVU79.95
Medicare national rate$2,670.40
Global period90 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

SettingMedicare rate (national)
Office (PFS non-facility)
Procedure performed in physician's office
$2,670.40
HOPD (APC 5114)
Hospital outpatient department
$7,413.38
ASC (PI J8)
Ambulatory surgical center (freestanding)
$4,682.29

Common denial reasons

The recurring reasons claims for CPT 20973 get rejected.

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

  • Billed in an outpatient or ASC setting — 20973 is Medicare inpatient-only (OPPS status indicator C)
  • Operative note omits microvascular anastomosis detail, failing to support the complexity of the code
  • Donor site not documented as great toe with web space, triggering a code-specificity mismatch
  • Related toe-to-hand transfer codes (26551, 26553, 26554, 26556) billed without checking NCCI bundling against 20973
  • Global period billing conflict — post-op visit billed without modifier 24 for unrelated E/M within the 90-day window

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01Is CPT 20973 payable in an ASC or hospital outpatient setting for Medicare?
No. CMS designates 20973 as inpatient-only under OPPS (status indicator C). Billing it in an ASC or outpatient hospital setting for Medicare patients will result in a non-covered denial. This restriction applies to the facility claim; the professional fee follows the site of service.
02What is the global period for 20973, and what does it cover?
20973 carries a 90-day global period. That covers the surgery, the day-before preoperative visit, and all routine postoperative care through day 90 — including flap monitoring, dressing changes, and suture removal. Bill unrelated E/M visits with modifier 24; return to OR for unrelated procedures with modifier 79.
03How does 20973 relate to toe-to-hand transfer codes like 26551 or 26553?
CMS crosswalk data lists 26551, 26553, 26554, and 26556 as potentially related to 20973. When a toe-to-hand transfer involves harvesting the great toe osteocutaneous flap, check NCCI edits before billing both codes for the same date of service. The Column 1 code will be paid; the Column 2 code requires a modifier if a separate, distinct service is documented.
04When is modifier 22 appropriate for 20973?
Append modifier 22 when the procedure involves substantially increased physician work beyond the typical case — for example, abnormal vasculature requiring extensive dissection, prior failed reconstruction, or severe scarring at the donor or recipient site. The operative note must describe the specific factors that increased complexity and time.
05If the patient returns to the OR for vascular compromise of the flap, how is that billed?
Use modifier 78 for an unplanned return to the OR for a complication related to the original procedure — such as re-exploration for arterial or venous thrombosis of the flap. Modifier 78 is for related return procedures. Modifier 79 is for unrelated procedures during the global period; do not use these interchangeably.
06Can 20973 be billed with a separate bone grafting code if additional graft is harvested?
Only if the additional graft harvest is from a completely separate donor site not already included in the flap harvest, and it serves a distinct reconstructive purpose. Document the separate site and clinical rationale clearly. Apply modifier 59 or XS and verify NCCI edits before submitting both codes.

Sources & references

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

  1. 01CMS Physician Fee Schedule 2026
  2. 02CMS OPPS Inpatient-Only List (Status Indicator C) — CMS-1427-P Addendum E
  3. 03
    aapc.com
    https://www.aapc.com/codes/cpt-codes/20973
  4. 04
    vsac.nlm.nih.gov
    https://vsac.nlm.nih.gov/context/cs/codesystem/CPT/version/2021/code/20973/info
  5. 05
    emedny.org
    https://www.emedny.org/providermanuals/physician/pdfs/physician%20procedure%20codes%20sect5.pdf
  6. 06
    aaos.org
    https://www.aaos.org/globalassets/advocacy/issues/2021-opps-pr-tables.pdf
  7. 07
    cgsmedicare.com
    https://www.cgsmedicare.com/medicare_dynamic/j15/partb/ptpb/ptp.aspx

Mira AI Scribe

Mira's AI scribe captures the donor site (great toe with web space), tissue components harvested (bone dimensions, skin paddle, vascular pedicle), recipient site defect description, and microvascular anastomosis detail directly from surgeon dictation. This prevents the most common audit flag for 20973: an operative note that describes a flap transfer without explicitly documenting the microvascular anastomosis or confirming the great toe as the harvest site.

See how Mira captures CPT 20973 documentation

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