Excision or curettage of a bone cyst or benign tumor located in the talus or calcaneus (ankle or heel bone), performed as an open procedure.

Verified May 8, 2026 · 7 sources ↓

Medicare: $645.31
Work RVU: 5.68
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCCgsmedicareAcgmeEmedny

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Identify the specific bone involved: talus or calcaneus — not 'ankle/heel bone' generically.
State lesion type (bone cyst vs. benign tumor) and size, confirmed by pre-op imaging or pathology.
Describe the surgical technique: excision, curettage, or combined approach, with extent of bone involvement.
Document that no bone graft was used; if graft was placed, 28100 is the wrong code.
Record approach and wound closure method to support medical necessity and defend against downcoding.
Include pre-operative imaging (X-ray, CT, or MRI) in the record linking the lesion to the talus or calcaneus.

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 50 Bilateral procedure 51 Multiple procedures 58 Staged or related 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 28100 covers open surgical removal or curettage of a bone cyst or benign tumor arising from the talus or calcaneus. The procedure involves direct exposure of the affected bone, excision or scraping of the lesion, and wound closure — without bone grafting. When the defect requires autograft or allograft fill, step up to 28102 or 28103 respectively.

The 90-day global period means all routine post-op visits, dressing changes, and wound checks through day 90 are bundled. Any E/M visit for an unrelated condition during that window needs modifier 24. A staged return to address a separate lesion or a planned second-stage reconstruction requires modifier 58, which resets the global clock.

Distinguishing 28100 from adjacent codes matters at audit. Use 28120 when the indication is osteomyelitis or extensive bone resection for infection — not benign tumor or cyst. Use 28104 for cysts in tarsal or metatarsal bones other than the talus or calcaneus. Operative note specificity on lesion type, exact bone involved, and technique (excision vs. curettage) is what survives a post-payment review.

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 (5.68) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (19.32) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	5.68
Practice expense RVU	12.75
Malpractice RVU	0.89
Total RVU	19.32
Medicare national rate	$645.31
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	$645.31
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI A2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 28100 get rejected.

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

Wrong code selected — 28120 (bone resection for infection) billed instead of 28100 for benign tumor/cyst, triggering a specificity denial.
Missing or vague pathology/imaging documentation that doesn't confirm a bone cyst or benign tumor at the talus or calcaneus.
Bone graft performed but not coded — payers flag 28100 when operative notes reference defect filling, indicating 28102 or 28103 was the correct code.
Unbundling: separately billing wound closure, casting, or splinting applied at the same operative session — NCCI bundles those services.
Global period conflict: post-op E/M visit billed without modifier 24 when the visit is within the 90-day window.

Frequently asked questions

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

01When should I use 28102 or 28103 instead of 28100?

Use 28100 only when no bone graft is placed. If you fill the defect with autograft (including harvesting), bill 28102. If you use allograft, bill 28103. Billing 28100 when the operative note documents graft placement will draw a mismatch denial or post-payment audit.

02What's the difference between 28100 and 28120 for ankle/heel lesions?

28120 is for partial excision of bone due to osteomyelitis, infection, or necrosis — not benign tumors or cysts. If your diagnosis is a bone cyst or benign neoplasm of the talus or calcaneus, 28100 is correct. Misapplying 28120 in a benign tumor case is a common audit finding.

03Can I bill 28100 bilaterally on the same date?

Yes, if cysts or tumors in both heels or ankles are addressed in the same session. Append modifier 50 for a bilateral procedure, or use LT and RT on separate line items depending on payer preference. Confirm with your MAC — some require RT/LT line-item billing over modifier 50.

04What ICD-10 codes pair cleanly with 28100?

M85.371–M85.379 (solitary bone cyst, ankle and foot) and D16.3 (benign neoplasm of short bones of lower limb) are the strongest medical necessity anchors. Specificity to laterality is required — D16.3 and M85.37x codes include laterality extensions. Unspecified diagnosis codes increase denial risk.

05Does the 90-day global period apply, and what can I still bill during it?

Yes — 28100 carries a 90-day global. Routine post-op visits are included and cannot be separately billed. You can bill E/M services for unrelated conditions with modifier 24, a new injury with modifier 79, or a staged procedure with modifier 58. Document clearly that the visit is unrelated to the index surgery when using modifier 24.

06Can 28100 be billed same-day with other foot and ankle procedures?

Yes, with modifier 51 on the secondary procedure when performed at the same session for a distinct anatomic site or separate lesion. Check NCCI PTP edits before billing any combination — casting or splinting applied at the same session cannot be separately billed per NCCI bundling rules for musculoskeletal codes.

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 bone (talus vs. calcaneus), lesion characterization (cyst or benign tumor), surgical technique (excision vs. curettage), graft status (none), and pre-op imaging reference directly from dictation. This prevents the most common audit flag for 28100 — operative notes that omit graft status or fail to name the exact bone — which forces manual review and risks downcoding to a lower-intensity excision code.

See how Mira captures CPT 28100 documentation