Open surgical treatment of a sesamoid bone fracture in the foot, with or without internal fixation such as pins or screws.

Verified May 8, 2026 · 5 sources ↓

Medicare: $323.32
Work RVU: 2.51
Global, days: 90
Region: Foot & ankle

Drawn from CMSAbosNIHAAPC

Documentation requirements

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

Source · Editorial brief grounded in 5 cited references ↓

Identify which sesamoid is involved — medial (tibial) or lateral (fibular)
Confirm open surgical approach is used, not closed or percutaneous
State whether internal fixation was applied and specify hardware type if used
Document imaging confirming fracture diagnosis (X-ray or CT) with date
Operative note must distinguish this procedure from sesamoidectomy (28315)
Record laterality — left or right foot — to support LT/RT modifier use

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 25 Significant separate E/M 51 Multiple procedures 52 Reduced services 57 Decision for surgery 58 Staged or related 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 28531 covers open treatment of a sesamoid fracture — most commonly involving the tibial or fibular sesamoid beneath the first metatarsophalangeal joint. The surgeon opens the surgical site, reduces the fracture, and stabilizes it with or without internal fixation hardware. Closed or percutaneous approaches do not map to this code.

This code carries a 90-day global period. All routine post-op visits, wound checks, and hardware monitoring through day 90 are bundled. Separately bill unrelated E/M visits with modifier 24, or a staged/related procedure in the global window with modifier 78. A new and unrelated procedure in the global window takes modifier 79.

Sesamoid fractures are uncommon, and documentation specificity drives clean claims. Operative notes must name the sesamoid involved (medial/tibial vs. lateral/fibular), confirm open approach, and detail fixation method — or explicitly state fixation was not used. Audit flags appear when notes are vague about approach or fail to distinguish this open procedure from a sesamoidectomy (28315).

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 (2.51) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (9.68) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	2.51
Practice expense RVU	6.96
Malpractice RVU	0.21
Total RVU	9.68
Medicare national rate	$323.32
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	$323.32
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 28531 get rejected.

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

Operative note describes closed or percutaneous approach, which does not support the open treatment code
Missing laterality documentation when LT or RT modifier is required by payer
Bundling with sesamoidectomy (28315) when only one procedure was performed
Insufficient imaging or diagnostic documentation to establish fracture diagnosis prior to surgery
Post-op E/M billed without modifier 24 during the 90-day global period

Frequently asked questions

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

01Does 28531 include internal fixation in the payment, or is that billed separately?

Internal fixation is included in 28531 regardless of whether hardware is used. The code description reads 'with or without internal fixation' — hardware is not separately billable.

02What modifier do I use if I'm billing 28531 on the same day as another foot procedure?

Use modifier 51 on the lower-valued code when billing multiple surgical procedures same-day, unless a payer-specific rule applies. If the procedures are on distinct anatomic sites, modifier 59 or XS may be appropriate to unbundle.

03Can I bill a post-op visit during the 90-day global period?

Only if it's unrelated to the sesamoid fracture treatment. Append modifier 24 to the E/M code and document that the visit addressed a separate condition. Routine post-op visits are bundled through day 90.

04How does 28531 differ from 28315 (sesamoidectomy)?

28531 is fracture repair — open reduction with or without fixation. 28315 is excision of the sesamoid. If the sesamoid is removed rather than repaired, 28315 applies. Billing both for the same sesamoid on the same date will draw a bundling challenge.

05Is a same-day E/M billable when 28531 is performed?

Only if a significant, separately identifiable decision for surgery was made at that same encounter for a condition distinct from the fracture itself. Append modifier 57 when the E/M led to the decision for surgery, or modifier 25 for a separate problem addressed on the same day.

06What ICD-10 codes typically pair with 28531?

S92.811A through S92.819A cover sesamoid fractures of the foot (initial encounter). Use the appropriate seventh character for encounter type — A for initial, D for subsequent, S for sequela — matched to the clinical context.

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 sesamoid involved (medial vs. lateral), confirmation of open approach, fixation method or explicit absence of fixation, and foot laterality directly from dictation. This prevents the two most common audit flags on 28531: vague approach language and missing laterality — both of which trigger payer requests for operative report review.

See how Mira captures CPT 28531 documentation