CPT code 28300: Calcaneal osteotomy billing and reimbursement

Key Takeaways

CPT Code 28300 describes osteotomy of the calcaneus (e.g., Dwyer or Chambers type procedure), with or without internal fixation, per the AMA CPT codebook.

For bilateral calcaneal osteotomies, bill 28300 as two separate line items with site modifiers (LT/RT) and modifier -59 on the second charge, not modifier -50 alone.

CPT 28300 carries a 90-day global surgery period, meaning post-op care within that window is not separately billable without appropriate modifiers.

Pabau’s claims management software helps orthopedic and podiatric practices track modifier rules, document global periods, and reduce calcaneal osteotomy claim denials.

CPT Code 28300 describes: Osteotomy; calcaneus (e.g., Dwyer or Chambers type procedure), with or without internal fixation. It sits within the Repair, Revision, and/or Reconstruction Procedures on the Foot and Toes section of the AMA’s CPT code set, and it applies whether or not hardware is placed during the procedure.

This article covers the code’s clinical context, correct modifier use, reimbursement benchmarks, NCCI and MUE rules, related codes, and the ICD-10 diagnoses that support it.

Clinical indications and procedure overview

Calcaneal osteotomies address structural deformities of the heel bone that cannot be corrected conservatively. The calcaneus is cut, repositioned, and stabilised to realign the subtalar joint and redistribute load through the foot.

CPT Code 28300 applies to several named techniques. The most common are:

• Dwyer osteotomy: A closing-wedge lateral calcaneal osteotomy used to correct calcaneal varus in cavovarus foot deformity.
• Chambers osteotomy: An opening-wedge procedure used in paediatric flatfoot correction.
• Evans osteotomy: A lateral column-lengthening osteotomy performed for pes planus (flatfoot). Confirmed by the AAPC Codify newsletter as appropriately reported with 28300.
• Medial displacement calcaneal osteotomy (MDCO): Shifts the calcaneal tuberosity medially to offload a dysfunctional posterior tibial tendon in adult flatfoot.

All four techniques are captured under 28300, regardless of whether screws, staples, or plates are used for fixation. The phrase “with or without internal fixation” in the descriptor makes hardware inclusion irrelevant to code selection. For practices managing physical therapy billing workflows alongside orthopedic care, this distinction matters for bundling decisions post-operatively.

CPT Code 28300 modifiers: Bilateral billing and distinct procedures

Modifier selection is where most 28300 claims go wrong. Two scenarios come up repeatedly in orthopedic and podiatric billing.

Bilateral calcaneal osteotomy

When both feet are operated on, do not use modifier -50 alone. Per NYSPMA coding guidance, bill 28300 as two separate line items: the first with the appropriate site modifier (LT or RT), and the second with the site modifier plus modifier -59 to establish the second procedure as a distinct service. Understanding procedure code modifier rules across surgical specialties reinforces why the two-line-item approach is preferred over modifier -50 in most payer contexts.

Concurrent procedures on the same foot

When 28300 is performed alongside a procedure such as 28310 (osteotomy of the proximal phalanx, first toe), modifier -59 on the secondary code establishes each as a distinct procedural service. Verify the current NCCI table before appending -59, since edit pairs change with each quarterly update.

Modifier reference table

Reimbursement rates for CPT Code 28300

Reimbursement for CPT 28300 varies by geographic location, facility type, and payer. The figures below reflect Medicare benchmarks. Commercial payers negotiate rates independently, often above Medicare amounts.

Always look up current-year rates using the CMS Physician Fee Schedule lookup tool or a dedicated RVU lookup tool like FastRVU before quoting expected reimbursement to a patient or payer. Rates are updated every January 1.

CPT 28300 carries a status indicator of J1 in the Medicare Physician Fee Schedule, reflecting a major surgical procedure with a 90-day global period. For surgical practice management teams handling foot and ankle surgery, tracking that global window accurately prevents inadvertent billing for included post-operative visits.

NCCI edits and MUE limits for CPT Code 28300

Two CMS edit systems govern how 28300 can appear on a claim alongside other codes.

NCCI bundling rules

The National Correct Coding Initiative (NCCI) identifies code pairs where one service is considered included in another. The pairing of 28300 with CPT 28740 (arthrodesis, midtarsal or tarsometatarsal joint) has been flagged in AAPC forum discussions and older AAOS global data books as potentially bundled, meaning 28300 may be considered included within 28740 when both are performed in the same operative session.

Verify the current NCCI edit table before submitting these together, since edit applicability depends on the specific joints fused and whether an NCCI modifier indicator permits unbundling. Review relevant medical billing code documentation practices to understand how NCCI exceptions are established.

MUE limits

Medically Unlikely Edits (MUEs) set a per-claim unit cap for each code. For 28300, the MUE limit is typically 1 unit per claim per day per provider. Billing two units on a single line triggers an automatic edit.

For bilateral calcaneal osteotomies, the correct approach is two separate line items (each with 1 unit), not a single line with 2 units, plus the modifier structure described in the modifiers section above. Confirm the current MUE value via CMS before submitting.

Global surgery period

CPT 28300 carries a 90-day global surgery period under the Medicare Physician Fee Schedule. All routine post-operative care during those 90 days is included in the surgical fee.

Follow-up office visits coded with E&M codes (99213, 99214) during the global window will be denied unless the visit is clearly unrelated to the surgery and documented as such with modifier -24 (unrelated E&M during global period) or modifier -79 (unrelated procedure during global period).

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Related CPT codes for calcaneal and tarsal osteotomy procedures

Code selection depends on the specific bone operated on and whether tendon transfer is included. Choosing the wrong code from this family is a common source of audits. These surgical procedure billing codes share structural similarities but differ in anatomical site and clinical intent.

When 28310 is performed at the same session as 28300 and on the same foot, verify the NCCI edit status and apply modifier -59 to 28310 if the edit pair permits an override. Review how CPT code billing guidelines handle same-session procedures in surgical contexts to inform your approach.

ICD-10-CM diagnosis codes for CPT Code 28300

Medical necessity requires linking CPT 28300 to an appropriate ICD-10-CM diagnosis code. The diagnosis must support the clinical rationale for the osteotomy. The following ICD-10 codes are commonly paired with 28300; payer Local Coverage Determinations (LCDs) govern which are accepted without additional documentation.

For broader context on ICD-10 diagnosis code crosswalks across specialties, the documentation principles are consistent.

• M21.6: Acquired deformities of ankle and foot (specify laterality with 4th/5th characters, e.g., M21.611 for right valgus deformity of right foot)
• M21.00: Valgus deformity, not elsewhere classified, unspecified site
• M66.871: Spontaneous rupture of other tendons, right ankle and foot (posterior tibial tendon dysfunction requiring MDCO)
• Q66.00: Congenital talipes equinovarus (clubfoot) variants requiring calcaneal correction
• Q66.50: Congenital pes planus (flatfoot), unspecified foot
• M21.4: Flat foot (acquired flatfoot or pes planus in adults)

Laterality must be specified at the highest level of detail available. Submitting an unspecified-laterality code when a more specific code exists is a common soft-coding error that payers flag during automated review. For additional context on surgical ICD-10 coding precision requirements, laterality specificity applies across all surgical specialties.

Documentation requirements for CPT Code 28300

Adequate documentation is the difference between a clean claim and an audit finding. For calcaneal osteotomy, payers want the operative report to establish three things: the specific deformity, the technique performed, and the hardware status.

Essential operative note elements

• Named technique (Dwyer, Chambers, Evans, MDCO) clearly stated in the operative report
• Anatomical site with laterality (right or left calcaneus)
• Whether internal fixation was used and what type (screws, staples, plate)
• Pre-operative diagnosis and how the clinical findings support surgical intervention
• Radiographic evidence supporting structural deformity (weight-bearing X-rays, CT, MRI as applicable)
• Conservative treatment history and duration, documenting that non-operative measures were attempted

The “with or without internal fixation” language in the CPT descriptor means hardware use does not change the code, but it must still be documented. Payers occasionally request implant documentation to verify coding of any separately billable supply items. Using digital surgical documentation templates ensures operative checklists capture every required element before the claim is submitted.

Prior authorisation

Most commercial payers require prior authorisation for CPT 28300 as a major elective surgical procedure. Requirements vary by plan. Aetna, UnitedHealthcare, and Cigna each maintain separate prior auth criteria for calcaneal osteotomy, typically requiring imaging and a documented failure of conservative care (minimum 3-6 months of physical therapy, orthotics, or casting). Confirm each patient’s specific plan requirements before scheduling.

Billing workflow for CPT Code 28300 in orthopedic and podiatric practices

A clean submission for 28300 follows a consistent sequence from surgical scheduling through to remittance posting. Practices that treat billing as a post-operative afterthought accumulate denials that take weeks to resolve.

1. Pre-auth verification: Confirm prior authorisation requirements for the specific payer and plan type before the procedure date. Note the auth number in the patient record.
2. Operative documentation: Surgeon completes the operative report on the day of surgery, naming the technique, laterality, and fixation status. Use templated notes to prevent omissions.
3. Code selection and modifier review: Billing team assigns 28300 with the appropriate site modifier and checks NCCI edit status for any concurrent codes (e.g., 28310, 28740). For bilateral cases, build the two-line-item structure with LT/RT and -59.
4. ICD-10 pairing: Link the correct diagnosis code with full laterality specificity to each CPT code on the claim.
5. Global period tracking: Enter the 90-day global start date into the practice management system. Flag any scheduled follow-up visits during that window for modifier review before submission.
6. Claim submission and remittance review: Submit electronically and monitor for remittance advice. Any denial citing NCCI, MUE, or modifier errors should be worked within 30 days to preserve appeal timelines.

Understanding medical billing code documentation standards across specialties reinforces why each step in this sequence exists. Pabau’s workflow tools support each stage, from digital intake through to claim tracking.

Conclusion

Calcaneal osteotomy claims fail most often at the modifier stage or the documentation stage, not because the code itself is wrong. Getting CPT Code 28300 right means pairing it with the correct site modifiers for bilateral cases, verifying NCCI edit status before bundling with 28740, and ensuring the operative note names the technique and laterality clearly.

Pabau’s practice management software helps orthopedic and podiatric practices build the documentation workflows, global period tracking, and claims management processes that keep surgical billing clean. Book a demo to see how Pabau supports foot and ankle surgery billing from operative note through to remittance.

Continue your research

Need a structured approach to surgical claims management? Pabau’s claims management software helps practices track modifier rules, global periods, and denial patterns across surgical codes.

Managing a multi-specialty foot and ankle practice? Digital forms allow surgical teams to build operative documentation checklists that capture every element payers require at the point of care.

Looking for guidance on related procedure codes? Bupa procedure codes fee schedule outlines how procedure-based billing works across different code systems and payer structures.

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