Surgical cutting and realignment of tarsal bones in the midfoot, excluding the calcaneus and talus, to correct deformity or relieve pain.

Verified May 8, 2026 · 6 sources ↓

Medicare: $871.76
Total RVUs: 26.1
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCFindacodeFastrvuGenhealth

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Identify the specific tarsal bone(s) involved (navicular, cuboid, medial/intermediate/lateral cuneiform) — 'midfoot bones' alone is insufficient.
Describe the type of osteotomy performed (opening wedge, closing wedge, dome, translational) and the degree of correction achieved.
Document the fixation method used (screws, plates, staples, pins, or no internal fixation) and implant details if applicable.
Record the clinical indication and failed conservative treatments that support surgical necessity (e.g., orthotics, physical therapy, duration).
Note the anesthesia type (regional vs. general) and operative positioning.
Confirm that calcaneus and talus were not the primary osteotomy sites, to support code selection over 28300 or talus-specific codes.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 58 Staged or related 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side AS PA/NP/CNS assistant

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 28304 covers osteotomy of the tarsal bones — specifically the navicular, cuboid, and cuneiform bones — excluding the calcaneus and talus. The surgeon cuts and repositions one or more of these midfoot bones, then stabilizes them with plates, screws, or pins. Indications include severe flatfoot (pes planus), cavus foot deformity, midfoot arthritis refractory to conservative care, tarsal coalition, traumatic bone deformity, and neuromuscular conditions affecting foot structure.

This is a 90-day global procedure. The global period covers the day-before preoperative visit, the day of surgery, and all routine postoperative care through day 90. Separate E/M visits within that window require modifier 24 (established patient, unrelated) or modifier 25 (new problem, same day as procedure). Staged or related return procedures in the global window use modifier 78; unrelated return procedures use modifier 79.

Distinguish 28304 from adjacent codes: osteotomy of the calcaneus uses 28300, and osteotomy of the talus is captured under different codes. If a dorsal midfoot exostectomy is performed without formal bone transection and realignment, consider whether 28104 (excision of bone cyst or benign tumor, tarsal) better reflects the work. Document the specific tarsal bone(s) cut, the type of osteotomy (opening wedge, closing wedge, translational), fixation method, and the clinical deformity being addressed.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.17
Practice expense RVU	15.47
Malpractice RVU	1.46
Total RVU	26.1
Medicare national rate	$871.76
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	$871.76
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 28304 get rejected.

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

Medical necessity not established — no documentation of failed conservative management prior to surgery.
Code mismatch with diagnosis: ICD-10 pointing to calcaneus or talus pathology triggers a cross-walk to 28300 or other codes, not 28304.
Operative note describes exostectomy or bone excision only, without formal osteotomy and realignment, prompting a downcode to 28104 or 28119.
Bilateral procedure billed without modifier 50 or separate LT/RT line items, resulting in a unilateral payment or rejection of the second claim line.
Global period conflict: a routine postoperative visit billed within 90 days without modifier 24 is denied as included in the global package.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01Does 28304 include the calcaneus or talus?

No. CPT 28304 explicitly excludes both. Calcaneal osteotomy is reported with 28300. If the operative target is the talus, review other tarsal codes — 28304 does not apply.

02Can 28304 be billed bilaterally?

Yes. If the osteotomy is performed on both feet in the same operative session, append modifier 50 for a single bilateral line, or bill LT and RT on separate lines per payer preference. Some commercial payers require RT/LT over modifier 50 — check individual payer policies.

03What modifier applies if a related procedure is needed during the 90-day global?

Modifier 78 covers an unplanned return to the OR for a complication or directly related issue within the global period. Modifier 79 applies when the return procedure is entirely unrelated to the original surgery.

04How does 28304 differ from 28104 when treating a midfoot exostosis?

28104 covers excision of a bone cyst or benign tumor from a tarsal bone without formal osteotomy and realignment. If the surgeon is simply removing a bony prominence, 28104 is the better fit. 28304 requires a purposeful bone cut and repositioning for deformity correction — the distinction must be clear in the operative note.

05Is an assistant surgeon payable on 28304?

CMS permits an assistant surgeon on this code. Bill with modifier 80 for an MD assistant or modifier AS for a PA or NP assistant, and confirm the primary surgeon's operative note documents why assistance was medically necessary.

06What ICD-10 diagnoses commonly support 28304?

Common supporting diagnoses include acquired flatfoot deformity (M21.4x), pes cavus (Q66.7x), tarsal coalition (Q66.89), midfoot post-traumatic deformity, and neuromuscular foot deformities. The diagnosis must match the specific bone and deformity documented in the operative report.

07Can 28304 be billed with modifier 22 for increased complexity?

Yes, if the procedure was substantially more complex than typical — for example, severe rigid deformity requiring multiple osteotomies, revision after prior failed surgery, or extensive intraoperative difficulty. The operative note must document the specific factors that increased time and effort, and most payers require a cover letter with the claim.

Sources & references

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

Mira AI Scribe

Mira's AI scribe captures the specific tarsal bone(s) cut, osteotomy technique (opening vs. closing wedge, translational), degree of angular correction, fixation hardware used, and the clinical deformity driving the procedure. This prevents the two most common audit flags: operative notes that name only 'midfoot osteotomy' without bone-level specificity, and missing documentation of conservative treatment failure required to support medical necessity on payer review.

See how Mira captures CPT 28304 documentation