CPT Code 28820: Amputation, toe; Metatarsophalangeal joint

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Key takeaways

CPT code 28820 describes surgical amputation of a toe at the metatarsophalangeal (MTP) joint. It sits in the Amputation Procedures on the Foot and Toes section of the CPT manual.

CMS reclassified CPT 28820 from a 90-day to a 0-day global period. Every post-operative visit is now billed separately with an E&M code.

Common billing errors include the old 90-day global assumption and a missing TA-T9 digit modifier. A claim without a linked ICD-10 code fails on medical necessity.

National Medicare payment runs roughly $290 to $300 in an office setting and $160 to $165 in a facility, before geographic adjustment.

Practice management software like Pabau can flag 0-day global period codes at scheduling and prompt billers to attach the digit modifier before submission.

CPT code 28820 covers amputation of a toe at the metatarsophalangeal joint, where the proximal phalanx meets the metatarsal head. The metatarsal itself stays intact.

CMS has since moved the code from a 90-day global period to a 0-day global period. That one change decides how every follow-up visit gets billed.

This reference covers the official descriptor, clinical indications, and global period mechanics. It also covers Medicare rates, applicable modifiers, ICD-10 crosswalk codes, documentation standards, and the neighboring amputation codes.

CPT code 28820: Definition and official descriptor

CPT code 28820 is defined by the American Medical Association as: Amputation, toe; metatarsophalangeal joint. The procedure removes a toe by disarticulation at the metatarsophalangeal joint. That separates the proximal phalanx from the metatarsal head without resecting the metatarsal.

This code sits within the Amputation Procedures on the Foot and Toes section of the CPT manual (codes 28800-28825).

It is a distinct anatomical level from CPT 28810, a ray amputation described as “Amputation, metatarsal, with toe, single”. CPT 28825 sits one joint further out, at the interphalangeal joint. Choosing the wrong level is one of the most common errors in podiatric surgical billing.

CPT 28820 code details at a glance

Use the quick-reference table below before submitting any claim for this procedure.

Clinical indications: When is CPT 28820 used?

CPT code 28820 is reported when a surgeon disarticulates a toe at the metatarsophalangeal joint. The scope here is billing and coding only. The decision to amputate rests with the treating physician, based on presentation and comorbidities.

Common clinical scenarios that drive this procedure include the diagnoses below. Each one needs a corresponding ICD-10 code to establish medical necessity with payers.

• Diabetic foot complications: Uncontrolled diabetes leading to gangrene, non-healing ulcers, or osteomyelitis of a toe is the most frequent indication. Peripheral neuropathy accelerates tissue necrosis when infections go undetected.
• Peripheral vascular disease (PVD): Arterial insufficiency causing tissue death in the distal digit, where revascularization is not feasible or has failed.
• Osteomyelitis: Bone infection of the proximal phalanx or the MTP joint that has not responded to antibiotic therapy.
• Traumatic injury: Crush injuries or severe lacerations where the toe cannot be salvaged.
• Malignant neoplasm: Tumors of the toe requiring surgical excision at the joint level.

Local Coverage Determinations (LCDs) issued by Medicare Administrative Contractors (MACs) define which diagnoses qualify for coverage. Coverage criteria vary by jurisdiction, so verify the applicable LCD for your region before submission.

Global period for CPT code 28820: The 0-day change explained

The most billing-disruptive change for CPT 28820 in recent years is CMS’s reclassification from a 90-day global period to a 0-day global period. Under a 90-day global, all post-operative care from the day of surgery through 90 days was bundled into the surgical payment.

Under a 0-day global, the surgeon’s fee covers only the day of surgery itself. The visual below shows what moves out of the surgical package, and which neighboring codes kept the 90-day designation.

CMS made this reclassification as part of its broader review of surgical global periods. The trigger was data showing that the clinical burden of post-operative care for minor foot procedures ran far below what the 90-day package implied.

The New York State Podiatric Medical Association (NYSPMA) and other specialty groups flagged the billing implications for practices treating diabetic populations with frequent follow-up needs.

How to bill post-op visits after a 0-day global period

After a 0-day global procedure, each post-operative visit is a separately billable encounter. Bill the appropriate E&M code for each visit rather than assuming it is included in the surgical payment.

1. Append modifier -24 to the E&M code to indicate an unrelated evaluation and management service during the post-operative period. For 0-day global codes this is technically not required, but some payers want it to avoid automatic bundling edits.
2. Document medical necessity for each visit. The visit note must stand on its own, describing wound status, patient concerns, or treatment changes. A bare progress note without clinical rationale will not support the charge.
3. Use the correct E&M level. Do not default to a low-complexity code if the visit warrants a higher level. MDM or time-based documentation determines the appropriate level under current CMS guidelines.
4. Link the correct ICD-10 diagnosis code. In most cases the post-op visit diagnosis reflects the post-surgical status or a complication, not the original surgical diagnosis. Verify with your MAC’s guidance.
5. Confirm payer-specific rules. Commercial payers may apply their own global period definitions. Some follow Medicare rules, others maintain their own policies. Check individual payer contracts.

Medicare reimbursement rates for CPT code 28820

Medicare reimburses CPT 28820 at different rates depending on the place of service. Facility rates apply in a hospital or ambulatory surgical center (ASC). Non-facility rates apply in an office setting.

The code carries 8.90 total non-facility RVUs and 4.84 total facility RVUs, with a work RVU of 3.42. Applying the 2026 conversion factor of $33.4009 produces the national figures below.

Both are subject to geographic adjustment via the Geographic Practice Cost Index (GPCI), so verify current amounts with the CMS Physician Fee Schedule lookup tool.

Submit claims through a clearinghouse that validates fee schedule compliance before they reach the payer. Practice management software like Pabau routes US claims through Claim.MD, which processes CMS-1500 and 837P files and returns electronic remittance advice for faster reconciliation.

Applicable modifiers for CPT code 28820

Modifiers are not optional for toe amputation claims. Missing or incorrect modifiers are a leading cause of denials and audits on CPT 28820 submissions. The table below covers the primary modifiers. Medicare modifier rules apply to Medicare claims, and commercial payer requirements may differ.

ICD-10 diagnosis codes commonly paired with CPT 28820

Every CPT 28820 claim requires at least one ICD-10 diagnosis code that establishes medical necessity. The table below shows the diagnoses linked most often. Acceptance depends on your MAC’s LCD for lower extremity amputations, so confirm coverage before submission.

Code to the highest level of specificity the clinical documentation supports. Our ICD-10-CM code library lists the full subcategories these diagnoses are drawn from, including the laterality and severity digits payers expect.

Specificity in the diagnosis code is what protects the claim from a medical necessity denial. A vague code invites a request for records even when the surgery was clearly indicated.

Documentation requirements for CPT 28820

Weak documentation is the fastest route to a post-payment audit or a recoupment demand on CPT 28820 claims. The operative note, pre-op evaluation, and follow-up records each have to meet specific standards. Every element of the claim needs to be traceable back to the medical record.

• Operative report: Names the specific toe and laterality, confirms the level of disarticulation, describes the surgical technique, and carries the attending surgeon’s attestation. It must state explicitly that the amputation happened at the MTP joint, which is what justifies 28820 over a related code.
• Pre-operative evaluation: Documents the conservative treatments that failed or were contraindicated, such as antibiotics, wound care, and revascularization. Payers expect a clinical history that supports surgical escalation.
• Medical necessity statement: The diagnosis appears in the record with enough clinical detail to support the linked ICD-10 code. A diagnosis code on the claim with no matching documentation is a common audit trigger.
• Informed consent: Signed, procedure-specific consent in the patient chart.
• Post-operative notes: Under the 0-day global, each follow-up visit needs its own complete documentation. A brief “wound looks good” note does not support a separately billed E&M visit.

Practices using structured digital charting capture these elements consistently. A properly completed operative note carries straight into the billing record, which cuts the manual work of assembling claim data later.

Related CPT codes: 28810, 28825, and the amputation series

The three primary toe amputation codes are distinguished by the anatomical level of resection. Selecting the wrong code in this series is a high-frequency audit finding. Review the distinctions below before coding any toe amputation procedure.

Note the global period difference. CPT 28810 retains a 90-day global period, while both 28820 and 28825 carry 0-day designations after the CMS reclassification.

A practice billing a metatarsal amputation with a 0-day global assumption will under-bill significantly. Check the AAPC CPT code range for the full amputation series to confirm current descriptors.

Common billing errors and how to avoid them

CPT 28820 claims fail for a predictable set of reasons. A denial management process should track these error types by category, so the pattern shows up before it becomes a quarter of lost revenue.

• Wrong global period assumption: Billing the procedure as if it carries a 90-day global, and not submitting separate E&M codes for post-op visits. This is the highest-frequency error since the CMS reclassification.
• Missing digit modifiers: Submitting CPT 28820 without a TA-T9 modifier. Medicare and most commercial payers require a digit-specific modifier on all toe procedures. Missing it causes automatic denial.
• Upcoding to CPT 28810: The operative report documents MTP joint disarticulation, but the biller submits 28810. The documented anatomical level has to match the billed code exactly.
• Unsupported ICD-10 pairing: Linking a non-specific diagnosis code, such as generic foot pain, when the record supports a specific diabetic foot or PVD code. The specific code is what carries the medical necessity argument.
• Inadequate operative documentation: The operative note does not state the level of amputation. Without that language, the claim is vulnerable to post-payment review.
• Unbundling errors: Separately billing a wound closure that is included in the amputation code. Review NCCI edits for 28820 before adding secondary procedure codes on the same date of service.

How practice management software supports CPT 28820 billing

Podiatry practices that treat diabetic foot populations perform toe amputations regularly. At that volume, prompting for digit modifiers and tracking global periods by hand stops working. Purpose-built claims management software moves both checks into the workflow the biller already uses.

Three specific capabilities matter most for CPT 28820:

• Global period flagging: When a biller or scheduler enters CPT 28820, the system flags the 0-day designation. The team is then prompted to bill each post-operative visit separately. That automation addresses the most common denial category for this code.
• Modifier prompting: Built-in modifier rules can require a TA-T9 digit modifier before a 28820 claim is cleared for submission. Claims that bypass this check create avoidable rework when the denial comes back.
• Claim scrubbing before submission: Automated validation checks the ICD-10 to CPT pairing and confirms modifier completeness. It also flags NCCI edit conflicts before the 837P file leaves the practice. Claims then route through Claim.MD, which returns real-time eligibility and electronic remittance advice (ERA) for faster reconciliation.

The outcome is fewer denials on a code whose denial reasons are already known. Billers stop relying on memory for the 0-day rule, and post-operative visits get charged on the day they happen instead of written off weeks later.

Billing CPT 28820 across multiple locations?

Pabau’s claims management software flags 0-day global period codes at scheduling, prompts billers to add digit modifiers, and routes claims through Claim.MD for electronic submission. See how it works for podiatry practices.

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Conclusion

Almost every denial pattern on CPT 28820 traces back to a billing workflow that was built for a 90-day global period. Rebuilding that workflow once costs less than appealing the same denial every month.

So the decision worth making now is where the check lives. A biller who has to remember the 0-day rule will eventually forget it on a busy Friday. A prompt at the point of coding will not.

Pabau embeds global period rules, modifier prompts, and claim scrubbing in the podiatry billing workflow. The checks then happen before submission rather than after a denial. Book a demo to see how it handles CPT 28820 and the rest of your podiatry claims.

Continue your research

Need to understand how clearinghouse submissions work for surgical codes? Pabau’s Claim.MD clearinghouse guide explains how 837P files are validated and transmitted to payers.

Looking for denial pattern analysis across your podiatry claims? Denial codes in medical billing covers the most common CARC codes and how to respond to each.

Want to understand how ERA remittances close the billing loop? Electronic remittance advice (ERA) breaks down the 835 transaction and how to reconcile payments efficiently.

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