CPT code 25393: Osteoplasty, radius and ulna lengthening

Key Takeaways

CPT code 25393 describes osteoplasty of BOTH the radius AND ulna with lengthening using autograft, distinguishing it from single-bone codes 25391 and 25392.

Documentation must confirm that the surgeon addressed both bones and harvested autograft, or claims risk downcoding to a single-bone code.

The global surgery period for CPT 25393 is 90 days; post-operative visits within that window are bundled and cannot be billed separately.

Pabau’s claims management software helps orthopedic and hand surgery practices track modifier application, global period rules, and prior authorization status in one workflow.

CPT code 25393: definition and clinical description

Orthopedic billing errors on forearm reconstruction cases often trace back to one documentation gap: failing to prove both bones were operated on. According to the American Medical Association’s CPT code set, CPT code 25393 specifically describes osteoplasty of the radius AND ulna with lengthening using autograft. The “AND” is load-bearing, both for clinical accuracy and for claim review.

CPT code 25393 sits within the AMA’s category of Repair, Revision, and/or Reconstruction Procedures on the Forearm and Wrist. Surgeons indicate this procedure when a patient presents with forearm length discrepancy affecting both bones simultaneously, whether from congenital anomaly, growth arrest following trauma, or post-infectious deformity. The surgeon performs osteotomies on both the radius and ulna, then uses harvested autologous bone graft to maintain the lengthened position while healing occurs.

Practices that handle claims management software workflows for hand and orthopedic surgery will encounter this code most often in pediatric and reconstructive contexts. Getting the documentation right before submission prevents payer audits and protects reimbursement.

Procedure description: what CPT 25393 involves

The procedure covered by CPT 25393 requires the surgeon to lengthen both forearm bones in a single operative session. This distinguishes it from staged procedures or situations where only one bone requires correction.

The operative steps typically include:

• Osteotomy of the radius: A controlled surgical cut through the radius to create the necessary gap for lengthening.
• Osteotomy of the ulna: A corresponding cut through the ulna, ensuring proportionate correction of both bones.
• Autograft harvest: Bone graft taken from the patient’s own body, most commonly the iliac crest, the surgeon shapes and packs it into the osteotomy gap to support bone bonding.
• Internal fixation: Plates, screws, or pins stabilize both bones while the graft incorporates and the lengthened segment consolidates.

Autograft harvest forms an integral part of this procedure. If the surgeon uses allograft (donor bone) or a synthetic substitute instead, CPT 25393 may not be the correct code. Coders should review the operative note carefully to confirm the graft source before submitting.

Coders following HIPAA-compliant documentation practices should ensure the operative report explicitly states bilateral bone involvement and the harvest site. Payer auditors looking at CPT 25393 claims will look for these two elements first.

CPT 25393 vs. related forearm osteoplasty codes

The 25391-25394 code family describes four distinct osteoplasty scenarios for the forearm. Choosing the wrong code is among the most common billing errors in this segment of musculoskeletal surgery.

The key distinction between CPT 25391 and CPT 25393 is the number of bones operated on. If the surgeon only lengthens the radius or only the ulna, 25391 applies. CPT 25393 requires both. Submitting 25393 when the surgeon addressed only one bone constitutes upcoding and exposes the practice to audit risk.

CPT 25394 covers a different anatomical region entirely, targeting carpal bones via shortening. It should not be confused with forearm lengthening procedures. AAPC Codify provides cross-referencing tools to verify adjacent codes when uncertainty exists about the correct selection.

Documentation requirements for CPT 25393

Payer reviewers evaluating CPT 25393 claims focus on three core elements. Missing any one of them can result in denial or downcoding to CPT 25391.

• Bilateral bone involvement: The operative report must clearly state that both the radius and the ulna were osteotomized and lengthened. Phrases like “forearm lengthening” without naming both bones are insufficient.
• Autograft confirmation: The note must state the graft was harvested from the patient’s own body, with the donor site identified (e.g., “left iliac crest autograft”). Absence of this language shifts the procedure outside CPT 25393’s descriptor.
• Pre-operative diagnosis justification: The clinical record should document the length discrepancy measurement and its functional or developmental impact, supporting medical necessity for bilateral correction.

When autograft harvest from a separate incision site occurs, coders should evaluate whether a separate CPT code for the harvest is appropriate. CMS guidelines on graft harvesting indicate that the primary procedure code includes harvest from the same surgical field; the practice may report harvest from a distinct, separate incision separately. Review the operative note for harvest site details before making this determination.

Practices building a medical practice billing workflow for surgical services should create a documentation checklist specific to CPT 25393. Flagging gaps before claim submission reduces denial rates and shortens revenue cycle times. Digital intake forms and structured operative templates capture required fields consistently across providers.

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Modifiers applicable to CPT 25393

Modifier selection directly affects reimbursement and audit exposure for CPT 25393 claims. The following modifiers are most relevant to this procedure.

Modifier 50: bilateral procedure

CPT 25393 already describes bilateral bone involvement (radius AND ulna). Modifier 50 applies to bilateral limb procedures, not bilateral bones within a single limb. Appending Modifier 50 to CPT 25393 would imply the surgeon performed forearm lengthening on both the left and right arms in the same session, which is a distinct clinical scenario. Do not append Modifier 50 simply because two bones were addressed in one forearm.

Modifier 22: increased procedural complexity

When the procedure required substantially more time or effort than typical, Modifier 22 may support a request for additional reimbursement. Examples include severe scarring from prior surgery, abnormal anatomy, or unusually extensive graft preparation. Modifier 22 claims require a written justification letter attached to the claim, documenting the specific factors that increased complexity. Without that letter, payers routinely ignore the modifier or issue a denial.

Modifier 51: multiple procedures

If CPT 25393 is performed alongside another distinct surgical procedure in the same session, Modifier 51 appended to the secondary procedure signals that multiple services were rendered. The primary (highest-value) procedure is billed without a modifier; subsequent procedures carry Modifier 51. Some payers apply an automatic payment reduction to secondary procedures.

Modifier 59: distinct procedural service

Modifier 59 is used when a procedure is distinct from another service billed on the same date, and National Correct Coding Initiative (NCCI) edits would otherwise bundle them. If autograft harvest is being billed separately and NCCI bundles it with CPT 25393, Modifier 59 on the harvest code may be appropriate, supported by documentation showing a separate incision site.

Orthopedic practices running sports medicine software alongside their surgical billing should ensure modifier logic is built into the claim review workflow. Modifier errors are a leading cause of underpayment on musculoskeletal surgery claims.

Reimbursement and Medicare payment for CPT 25393

CPT 25393 carries a relatively high work RVU value, reflecting the complexity of bilateral forearm bone lengthening with autograft. Because the Medicare Physician Fee Schedule is updated annually and varies by geographic practice cost index (GPCI), always verify specific dollar figures against the current year’s data. Use the CMS Physician Fee Schedule Look-Up Tool to retrieve the most current non-facility and facility payment rates for your MAC jurisdiction.

Key reimbursement concepts that affect CPT 25393 payment:

Facility and non-facility payment rates

• Facility vs. non-facility rates: When performed in a hospital operating room or ambulatory surgical center (ASC), the non-facility rate applies to the physician’s professional component only. The facility bills separately for overhead. Non-facility rates (office-based surgery) are higher because the physician absorbs overhead costs directly.

Global surgery period and bundled services

• Global surgery period: CPT 25393 carries a 90-day global surgery period under Medicare. Medicare bundles all post-operative evaluation and management visits within that window into the surgical fee; you cannot bill them separately. The global package also includes pre-operative visits within 24 hours of the scheduled surgery date.

RVU lookup

• RVU lookup: Use FastRVU’s 2026 RVU lookup tool to retrieve work RVU, practice expense RVU, and malpractice RVU values for CPT 25393, then apply your locality’s conversion factor for an estimate of Medicare allowable.

Prior authorization requirements

Prior authorization requirements vary significantly by payer. Kaiser Permanente Washington has removed CPT 25393 from its authorization-required code list for elbow and arm treatment according to publicly available provider billing references, but verify authorization requirements for other commercial payers and state Medicaid programs directly with each payer before scheduling.

Practices using a practice management platform with integrated billing should configure payer-specific authorization rules for CPT 25393 to prevent submission without required approvals. Automated billing workflows can flag cases requiring prior authorization at the time of scheduling, not at the time of billing, which is where the real revenue protection happens.

ICD-10 diagnosis codes commonly paired with CPT 25393

Medical necessity for CPT 25393 must be supported by an appropriate ICD-10-CM diagnosis code. Payers use the diagnosis code to evaluate whether forearm lengthening of both bones is clinically justified. The CMS ICD-10-CM code files contain the complete, annually updated listing of valid diagnosis codes.

Common ICD-10-CM codes paired with CPT 25393:

Laterality matters. ICD-10-CM requires site-specific coding wherever available. An M21.731 code indicates the right forearm; M21.732 indicates the left. Submitting without a laterality-specific code where one exists may trigger a payer edit requesting additional information.

Practices using structured client record management can flag laterality information at the intake stage, reducing the likelihood of vague diagnosis code selection at billing time.

NCCI edits and MUE values for CPT 25393

The National Correct Coding Initiative (NCCI) maintains edit pairs that bundle procedure codes which are typically performed together or considered part of the primary service. Before billing CPT 25393 alongside any other forearm procedure code, coders should check for NCCI column 1/column 2 edit conflicts.

The Medically Unlikely Edit (MUE) for CPT 25393 limits the number of units that can be billed for a single beneficiary on a single date. Because CPT 25393 already describes bilateral bone involvement within a single forearm, CMS typically sets the MUE value at 1 unit per date of service. Submitting more than 1 unit without a valid modifier and supporting documentation will result in automatic denial of the excess units.

Coders should also check whether any planned secondary procedure code is subject to NCCI bundling with CPT 25393. Common bundling conflicts arise when autograft harvest (when billed separately) or internal fixation codes are submitted alongside the primary osteoplasty code without appropriate modifier documentation.

Practices managing high volumes of musculoskeletal surgical claims benefit from medical practice management software that incorporates edit checking at the pre-submission stage, catching NCCI conflicts before claims leave the practice.

Billing workflow for CPT 25393 in orthopedic practices

A clean CPT 25393 claim requires coordination across scheduling, clinical documentation, and billing. Practices that treat these as separate silos see the highest denial rates on complex surgical codes.

1. At scheduling: Verify payer authorization requirements. Some commercial payers require prior authorization for forearm reconstructive surgery. Document the authorization number and attach it to the patient’s record before the operative date.
2. At pre-operative documentation: Confirm the clinical record documents the forearm length discrepancy measurement, bilateral involvement rationale, and the planned surgical approach.
3. At claim creation: Select CPT 25393 as the primary procedure. Attach the correct laterality-specific ICD-10-CM diagnosis code. Review for NCCI edit conflicts if secondary procedures are being billed on the same date.
4. At modifier review: Apply Modifier 22 only if complexity is documented in the operative note. Verify Modifier 50 is not mistakenly applied unless the procedure was performed on both arms.
5. At post-operative tracking: Flag the global surgery period end date (90 days from the date of surgery). Ensure post-operative E/M visits within the global period are not billed separately to Medicare or Medicare Advantage plans.

Practices handling physical therapy EMR workflows alongside surgical billing often find that post-operative rehabilitation visits in the global period require separate communication between the therapy team and the billing department to avoid accidental separate billing.

Hand surgery practices that invest in EHR integration between their clinical and billing systems reduce the manual handoff errors that commonly affect surgical code accuracy. When the operative note feeds directly into the billing workflow, the system catches documentation gaps before submission rather than after denial.

Conclusion

CPT code 25393 is a low-volume but high-complexity code that rewards careful documentation and pre-submission review. The most preventable errors are billing it for single-bone procedures and failing to confirm autograft harvest in the operative note.

For orthopedic and hand surgery practices managing CPT 25393 claims, Pabau’s claims management tools support modifier tracking, global period alerts, and pre-authorization workflows within a single platform. See how it handles complex surgical billing by booking a demo.

Frequently Asked Questions