CPT code 28308: Metatarsal osteotomy billing, modifiers, fee schedule

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Key takeaways

CPT code 28308 describes an osteotomy of the metatarsal other than the first, with or without lengthening, shortening, or angular correction.

Modifier LT or RT is required when billing for a single foot. Modifier 59 or XS may be needed to unbundle CPT 28308 from hammertoe code 28285.

Medicare pays about $585 for CPT 28308 in an office and about $372 in a facility, before GPCI adjustment.

The 90-day global period means post-op visits, dressing changes, and routine follow-up care within that window cannot be billed separately under most payers.

Pabau’s claims management software streamlines metatarsal osteotomy billing by flagging NCCI edit conflicts and tracking claim status through your clearinghouse.

CPT code 28308 covers an osteotomy of the metatarsal other than the first metatarsal, with or without lengthening, shortening, or angular correction. The American Medical Association (AMA), which maintains the CPT code set, places this code within the Surgery section under Musculoskeletal System, Foot procedures.

The procedure involves surgically cutting one of the lesser metatarsals (second through fifth) and repositioning it to correct a structural deformity. Common indications include metatarsalgia, bunionette (tailor’s bunion), transfer lesions, and lesser-toe deformities that need metatarsal realignment.

CPT code 28308 applies per metatarsal treated, but only when a single lesser metatarsal is addressed. When two or more lesser metatarsals receive osteotomies in the same session, CPT 28309 is the correct code.

Modifiers for CPT code 28308

Selecting the right modifier is one of the most frequent sources of claim denials for CPT code 28308. Because osteotomies can be performed on either foot or on multiple toes, laterality and distinctness modifiers are both relevant.

Payer-specific rules govern which modifier resolves an NCCI bundle. Medicare currently prefers XS over 59 in most situations involving separate anatomical structures, but commercial payers may still require 59. Always verify the modifier policy with the individual payer before submitting. Never assume a modifier guarantees reimbursement: The operative note must independently support each code.

Reimbursement and fee schedule for CPT code 28308

CPT code 28308 reimbursement varies by payer, geographic location, and facility type. The CMS Physician Fee Schedule lookup tool is the authoritative source for Medicare payment rates. Those rates are then adjusted by Geographic Practice Cost Indices (GPCI) for each locality.

2026 Medicare payment rates for CPT 28308

The figures below are national averages for 2026, priced at the $33.40 conversion factor. Actual payment depends on the locality GPCI and on whether the service is performed in a facility or non-facility setting. Verify current rates using the FastRVU 2026 lookup tool or the CMS MPFS database.

The site of service moves the payment more than any other variable. Physician work and malpractice RVUs are identical in both settings, so the entire difference sits in practice expense. An office-based osteotomy pays roughly $585, while the same procedure in a hospital or ASC pays about $372.

RVU values and conversion factors are subject to annual CMS updates. Geographic GPCI multipliers can shift the final payment up or down by 15-25% depending on locality.

Commercial payers typically reimburse at a contractual multiplier of the Medicare fee schedule, usually 100% to 130%. Practice management software like Pabau gives billing teams end-to-end claims management. Each CPT 28308 claim is tracked from submission through ERA receipt, and underpayments surface automatically.

ICD-10 diagnosis codes that support medical necessity

Accurate diagnosis coding is a prerequisite for medical necessity. Payers use diagnosis codes to decide whether the procedure is covered under their Local Coverage Determination (LCD) policies for foot surgery.

The ICD-10-CM codes below are the ones most often crosswalked with CPT code 28308. Coverage decisions are still governed by individual payer LCDs, not by the crosswalk list.

Use the CrossCoder CPT-to-ICD-10 crosswalk tool to verify which diagnosis codes align with CPT code 28308 under your MAC’s LCD. A crosswalk list is never a substitute for reading the payer’s own policy. Document the specific deformity, the affected metatarsal, and the functional limitations in the operative record.

CPT 28308 vs. CPT 28309: Key differences

Choosing between CPT 28308 and CPT 28309 is one of the most common coding decisions in podiatric surgery. The rule is straightforward in principle but frequently misapplied when multiple metatarsals are addressed in a single session.

A common error is billing CPT 28308 twice for two metatarsals on the same foot. That scenario requires CPT 28309, not two units of 28308. Confirm which metatarsals were surgically cut in the operative report before code selection, because unbundling violations carry audit risk.

Units mean something different on a drug line. HCPCS code J2700 is defined as up to 250 mg of oxacillin sodium, so a 1,000 mg dose is reported as four units.

Related CPT codes in the 28300 family

CPT code 28308 sits within a family of foot osteotomy codes. Knowing where each code starts and stops is what prevents a misapplied code on a multi-procedure claim.

Billing CPT 28308 with CPT 28285: NCCI bundling rules

The most common billing challenge for CPT code 28308 is its interaction with CPT 28285 (correction of hammertoe with or without tenotomy). The National Correct Coding Initiative (NCCI) may bundle the two codes. Hammertoe correction and metatarsal osteotomy are sometimes treated as components of one surgical encounter on the same toe ray.

Before assuming both codes can be billed, check the current medical billing denial codes tied to NCCI edit violations for this pair.

NCCI edit tables are updated quarterly by CMS. What resolves a bundle in one quarter may not apply in the next. Verify the current edit status via the AAPC Codify CPT lookup or directly through CMS NCCI policy documentation before submitting.

When separate billing of 28308 and 28285 is supportable

Both codes can be billed in the same session when each procedure is clinically distinct and independently documented. The operative report must demonstrate:

• The hammertoe correction (28285) addressed the digital deformity (flexion contracture, plantar plate dysfunction)
• The metatarsal osteotomy (CPT code 28308) addressed a separate underlying skeletal deformity, such as metatarsal length discrepancy or angular deviation
• Each procedure required separate incision sites, surgical technique, and individual documentation
• Modifier 59 or XS is applied to the column-2 code (generally 28308 in this pairing), with full documentation supporting the modifier

Payer policies differ on which modifier resolves this NCCI edit. Medicare guidance currently favors the X modifiers (XS, XU, XP, XE) over modifier 59, but individual commercial payers may still require 59. Confirm with each payer before submission.

Missing documentation to support the unbundling is the single most common reason these claims are denied on audit review. The coding rules on the hammertoe side of the pair sit on the CPT 28285 reference page.

What the documentation must prove

A defensible CPT code 28308 claim rests on the operative report. Coders cannot create documentation that does not exist. The report, the pre-operative workup, and the office notes must together support every element of the code descriptor.

Required elements in the operative report

• Specific metatarsal identified: state which metatarsal (second, third, fourth, or fifth) was cut, with laterality (left or right foot)
• Type of correction performed: document whether the osteotomy involved lengthening, shortening, angular correction, or a combination; this directly matches the code descriptor language
• Incision and technique: describe the surgical approach, fixation method (K-wire, screw, staple), and any hardware used
• Pre-operative diagnosis: document the deformity type and severity, including failed conservative treatment (orthotics, shoe modifications, injections) with dates
• Post-operative diagnosis: confirm the diagnosis was consistent with pre-operative findings

The standard is the same across every surgical specialty. The operative note must match the code descriptor closely enough that an auditor would independently select the same code. Vague language such as “osteotomy performed on the foot” creates denial exposure, because it names neither the metatarsal nor the correction type.

Pre-authorization requirements for CPT code 28308 vary by payer. Many commercial plans require prior authorization for elective foot surgery. Contact the patient’s insurer to confirm requirements before scheduling.

Global period and post-operative billing

CPT code 28308 carries a 90-day global period under the CMS Medicare Physician Fee Schedule, consistent with its classification as a major surgical procedure. Confirm this via the CMS MPFS database, since global periods can change with annual updates. Knowing what falls inside and outside that window prevents both underbilling and overbilling.

Services included in the 90-day global period

• Routine post-operative office visits related to the metatarsal osteotomy
• Dressing changes and wound care performed by the surgeon or their staff
• Removal of sutures, staples, K-wires, or other fixation devices that are part of the normal post-operative course
• X-rays ordered to monitor osteotomy healing progress

Services billable outside the global period

• Treatment of a new or unrelated condition that arises during the global period
• Staged procedures planned from the outset and documented as separate surgical events
• Complications requiring a return to the operating room (modifier 78)
• Unplanned return for a complication not directly attributable to the original surgery (modifier 79)

Flag the global period status on every post-operative visit in the schedule. That single field stops duplicate billing and tells the billing team when the 90-day window opens and closes. Reconcile each remittance against it, so global and non-global services are paid as billed.

Common billing errors and how to prevent them

Six errors account for most CPT code 28308 denials in audits and payer appeals. Each one is caught by a structured pre-submission review, so build these checks into the workflow before claims go out.

Top errors to avoid

• Using 28308 twice for two metatarsals on the same foot: this should be CPT 28309. Two units of 28308 on the same foot in the same session is an NCCI violation.
• Missing laterality modifier: Medicare and most commercial payers require LT or RT. Claims submitted without a laterality modifier for procedures that are inherently unilateral (foot surgery) are commonly rejected or denied outright.
• Applying modifier 59 without supporting documentation: modifier 59 on the 28308 / 28285 pairing requires explicit operative note language showing separate, distinct procedures. The modifier alone does not make the claim payable.
• Submitting without a prior-auth number when required: commercial payers frequently require pre-authorization for elective osteotomies. Failing to obtain authorization before surgery leaves the claim unprotectable on appeal.
• Using vague diagnosis codes: coding M79.671 (foot pain) as the primary diagnosis when a more specific deformity code (M20.4x, M77.4x) exists risks medical necessity denial. Always code to the highest level of specificity supported by documentation.
• Incorrect global period billing: billing a routine 2-week post-op visit as a standard E/M during the 90-day global period is a compliance violation. These visits are bundled into the global package.

Three checks catch most of these errors before submission:

• An NCCI edit run against the full claim
• A modifier validity review for laterality and distinctness
• Automated claim scrubbing at the clearinghouse

Run them as one step in the billing workflow, not as three optional habits.

How claims management software prevents CPT 28308 denials

A lot of podiatry billing runs on one person’s memory. The biller knows CPT 28308 needs LT or RT, knows the 28285 edit exists, and knows which post-op visits fall inside the 90-day window. When that person is out, the denials arrive three weeks later.

Pabau holds the operative note, the diagnosis codes, the modifiers, and the claim in one record. The checks then run against the chart rather than a checklist taped to a monitor. Claims go out electronically, and each remittance comes back with the denial reason code attached to the claim line it belongs to.

The outcome is fewer avoidable denials on foot surgery codes, and a shorter appeal list for the billing team to work through. Every Pabau subscription includes claims management, reporting, and clinical records, so none of this sits behind a higher tier.

Streamline metatarsal osteotomy billing from claim to payment

Pabau’s claims management connects to your clearinghouse to track CPT 28308 claims and catch NCCI edits before submission. Denial reasons come back attached to the claim line, so the billing team stops chasing payments.

Book a demo

Conclusion

The code choice on a metatarsal osteotomy is rarely the hard part. One lesser metatarsal is 28308, two or more is 28309, and the operative report settles which. Payment turns on what happens after the code is picked.

So the work worth doing sits upstream of the claim. If the operative note names the metatarsal, the laterality, and the correction type, the modifier follows and the audit defense is already written. If it does not, no modifier rescues the claim on appeal.

Set that pre-submission check once and it holds for every foot surgery code, not only this one. Book a demo to see how Pabau tracks a CPT 28308 claim from the operative note through the remittance.

Continue your research

Need a primer on clearinghouse claim submission for foot surgery codes? Medical claims clearinghouse overview covers how electronic claim routing works and what to look for in a clearinghouse for surgical specialties.

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