ICD code S42.226P – Nondisplaced humeral surgical neck fracture with malunion

Key takeaways

S42.226P is a billable ICD-10-CM code for a follow-up visit after a 2-part nondisplaced surgical neck fracture of the humerus that healed with malunion.

The 6th character 6 means the record does not say which arm, so code S42.224P (right) or S42.225P (left) whenever the side is documented.

Category S42 tells you to code a fracture to displaced when the record is silent, so the note must state nondisplaced before S42.226P applies.

The 7th character P needs a documented malunion, meaning the fracture healed out of position, confirmed on imaging or in the physician’s note.

Pabau, the practice management platform we build, sends insurance claims from the invoice and flags denied fracture follow-up claims for rework.

What is ICD-10 code S42.226P?

ICD-10 code S42.226P is the billable diagnosis code for a 2-part nondisplaced fracture of the humeral surgical neck that healed with malunion. It is used at a follow-up visit when the record does not state which arm. It is billable for the current fiscal year, per the CMS and CDC ICD-10-CM code set for FY2027, effective October 1, 2026.

Three facts decide whether it fits a claim. The fracture is a 2-part fracture of the surgical neck, recorded as nondisplaced. The record does not name the right or left arm. The visit is follow-up care for a fracture that united in an abnormal position.

What S42.226P means: Breaking down each character

Each segment of S42.226P narrows the diagnosis. Reading them in order shows where the common substitution errors come from.

• S42: Fracture of shoulder and upper arm. The category covers clavicle, scapula, and humerus fractures.
• .2: Fracture of upper end of humerus, also called the proximal humerus. Shaft fractures sit in S42.3- and lower-end fractures in S42.4-.
• .22: 2-part fracture of surgical neck of humerus. Greater tuberosity fractures sit in S42.25- and lesser tuberosity fractures in S42.26-.
• .226: Nondisplaced fracture, unspecified humerus. In S42.22-, characters 1 to 3 are displaced (right, left, unspecified) and 4 to 6 are nondisplaced (right, left, unspecified).
• P: Subsequent encounter for fracture with malunion. This 7th character records the episode of care and the healing outcome.

Two different facts sit in one code. “Nondisplaced” describes the fracture as it was classified at injury. “Malunion” describes how it healed, so a fracture recorded as nondisplaced can still unite out of position. The 7th character P reports that healing outcome without changing the original classification.

Category S42 also carries a default rule: A fracture not indicated as displaced or nondisplaced should be coded to displaced. If the record never says “nondisplaced”, the default code is S42.223P, not S42.226P.

Anatomy: The surgical neck of the humerus

The surgical neck is the narrowed section of the humerus just below the greater and lesser tuberosities. It marks the junction between the proximal humerus and the shaft. It is a common site of proximal humerus fracture, often after a fall onto an outstretched arm.

The axillary nerve and the posterior circumflex humeral artery wrap around this region. That is why the surgical neck is examined closely at the initial encounter. A fracture that heals angled or shortened can limit shoulder elevation and rotation. That loss of motion is what brings the patient back for a malunion visit.

Neighboring structures each have their own code groups. Choosing S42.226P over them depends on the record naming the surgical neck and a 2-part pattern:

• S42.21-: Unspecified fracture of surgical neck of humerus, used when the number of parts is not documented. S42.211 is an unspecified displaced fracture of surgical neck of right humerus.
• S42.23- and S42.24-: 3-part and 4-part fractures of surgical neck of humerus.
• S42.25-: Fracture of greater tuberosity of humerus.
• S42.26-: Fracture of lesser tuberosity of humerus. S42.261P is the displaced right-side lesser tuberosity malunion code.
• S42.3-: Fracture of shaft of humerus, which category S42.2 excludes.

Understanding the 7th character P: Subsequent encounter with malunion

The 7th character P in ICD-10-CM fracture codes means the patient is seen for follow-up care after a fracture that healed in an abnormal position. Under the ICD-10-CM Official Guidelines (Section I.C.19.c), the encounter and the healing status set the 7th character. Time since injury does not.

Full 7th character table for S42.226

Category S42 has seven 7th characters. Unlike some lower-limb categories, it does not split subsequent encounters by open and closed fracture. P therefore applies to a malunion whether the original fracture was open or closed.

A subsequent-encounter code also applies when a different provider sees the patient. A physical therapist treating the patient later uses D, G, K, P, or S by healing status. The therapy visit is not active fracture treatment.

Malunion vs. nonunion: Choosing between S42.226P and S42.226K

Malunion means the fracture has healed, but in an abnormal position. Nonunion means the fracture has failed to heal, so the bone ends have not bridged. The two are opposite outcomes, with different codes and often different treatment plans.

When imaging is mixed, such as partial bridging with a persistent line, query the treating physician before coding. The physician’s documented diagnosis drives the 7th character.

Codes commonly confused with S42.226P

Most substitution errors on S42.226P involve the same fracture with a different side, displacement, or 7th character. The table maps the frequent ones.

Clinical documentation requirements for S42.226P

The CMS ICD-10-CM coding guidelines require the code to match the record. For S42.226P, the clinical record needs these elements:

• Fracture site: The note, operative report, or radiology report names the surgical neck of the humerus. “Proximal humerus fracture” alone points to S42.20- or S42.29-, not S42.22-.
• Fracture pattern: The record describes a 2-part fracture. Without a part count, S42.21- is the closer match.
• Nondisplaced: The record states the fracture was nondisplaced. If displacement is not documented, the S42 default rule sends the code to displaced, S42.223P.
• Laterality: S42.226P is for a record that does not state the side. If the right or left arm is documented anywhere in the record, use S42.224P or S42.225P.
• Malunion confirmed: An X-ray or CT report states the fracture healed out of alignment, or the physician’s note documents malunion with reference to imaging.
• Subsequent encounter context: The note makes clear this is follow-up care, such as “seen in follow-up for surgical neck fracture with malunion”.

Claims management software that keeps the note, the codes, and the claim in one record makes these checks quicker. A coder can confirm side and displacement in the chart before the claim leaves the practice.

CPT codes commonly paired with S42.226P

S42.226P is paired with different CPT codes depending on the setting and the service. The table covers common pairings by provider type. Check current NCCI edits before submitting any combination, because bundling rules change quarterly.

Pabau’s Claim.MD clearinghouse integration submits claims electronically from the invoices you already raise and tracks each claim’s status. Denied claims are flagged in Pabau for rework, so a fracture follow-up claim does not sit unnoticed.

Top reasons S42.226P claims are denied

Subsequent-encounter malunion codes can draw more documentation requests than initial-encounter fracture codes. Good denial management workflows start with the errors that trigger them.

• Wrong 7th character: A or B on a follow-up visit, or D when malunion has been documented. The 7th character must match the encounter and the healing status on the date of service.
• Missing malunion documentation: P submitted without a note or imaging report that states malunion. “Patient returns for fracture follow-up” supports D, not P.
• Laterality available but not coded: S42.226P billed when the note names the right or left arm. Use S42.224P or S42.225P in that case.
• Displacement not documented: S42.226P billed when the record never says nondisplaced. The S42 default points to the displaced code, S42.223P.
• Wrong fracture site: A surgical neck code billed for a tuberosity or shaft fracture, or for a “proximal humerus fracture” with no site named.
• Medical necessity not established: Surgery CPT codes paired with S42.226P need a documented functional deficit, pain scores, and failed conservative care.

Billing S42.226P for physical therapy and rehabilitation

Physical and occupational therapists often report subsequent-encounter fracture codes as the primary diagnosis during rehabilitation. S42.226P fits a therapy claim when the patient is treated for a surgical neck fracture that healed with malunion. Examples include range-of-motion restoration, shoulder strengthening, and functional retraining after corrective surgery.

The plan of care must document the malunion and link the therapy goals to the limits it causes. A goal such as “restore shoulder elevation and rotation following surgical neck malunion” makes that link clear.

Check the referral for laterality too. A therapy referral usually names the treated arm, and then S42.224P or S42.225P is the correct code. Practices using physical therapy EMR software with structured templates can capture side, displacement, and malunion at the point of care.

Choose the 7th character by the problem the therapy episode addresses. Use P when the malunion itself drives the plan of care. Use S for late effects, such as persistent stiffness, once the malunion has been treated.

Payer requirements and prior authorization

Requirements for S42.226P vary by plan type. Knowing each payer class’s baseline cuts authorization delays. The medical billing fundamentals that govern claim submission apply across all of them.

• Medicare: Follow-up visits need documented medical necessity. Corrective surgery is reviewed against the documented functional deficit and the conservative treatment already tried.
• Commercial insurers: Many require prior authorization for corrective osteotomy or other elective shoulder surgery. Confirm the requirement before scheduling, because retroactive approval is hard to obtain.
• Workers’ compensation: Carriers usually require documentation linking the malunion to the work injury. The file should hold the original injury report and any independent medical examination findings.
• Medicaid: Coverage and prior authorization rules vary by state program and managed care plan. Check with the applicable plan before treatment.

Includes and excludes notes for S42.226P

The tabular notes for S42.226P sit at two levels, the category S42 and the subcategory S42.2. Coding an Excludes1 condition alongside S42.226P on the same claim triggers payer edits.

• Excludes1 at S42: Traumatic amputation of shoulder and upper arm (S48.-). It cannot be coded with S42.226P.
• Excludes2 at S42: Periprosthetic fracture around internal prosthetic shoulder joint (M97.3-). It is not part of S42, but both may be coded when both are present.
• Excludes2 at S42.2: Fracture of shaft of humerus (S42.3-) and physeal fracture of upper end of humerus (S49.0-).
• Includes at S42.2: Fracture of proximal end of humerus.
• Category notes at S42: A fracture not indicated as displaced or nondisplaced is coded to displaced. A fracture not indicated as open or closed is coded to closed.

Check the CDC/NCHS ICD-10-CM browser tool or the AAPC Codify ICD-10-CM lookup for the fiscal year of service. Notes are updated each October and occasionally mid-year.

How claims management software reduces errors on S42.226P claims

Many practices still code fracture follow-ups in one system and submit claims in another. The coder re-keys the diagnosis, and a missing side or 7th character only surfaces when the payer responds.

In Pabau, the claim is generated from the invoice for the visit, so the diagnosis travels with the patient record. Claims go to the payer through the Claim.MD clearinghouse, eligibility can be checked before treatment, and remittances post back against the claim.

When a payer denies an S42.226P claim, Pabau flags it for rework next to the clinical note. Your team can then correct the side or the 7th character and resubmit without leaving the record.

Reduce denials on fracture follow-up claims

Pabau generates insurance claims from your invoices, submits them through Claim.MD, and flags denials for rework. See how orthopedic and therapy practices keep S-code claims moving.

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Conclusion

S42.226P is a narrow code. It fits only when the record calls the surgical neck fracture 2-part and nondisplaced, leaves the side unstated, and confirms malunion at a follow-up visit.

Before you bill it, look for the side in the referral, the imaging report, and the operative note. A documented side moves the claim to S42.224P or S42.225P. A missing “nondisplaced” moves it to S42.223P. A short query to the provider costs less than a denied claim.

Practices that keep notes, codes, and claims in one place catch these mismatches before submission. The clean claim habit pays off most on subsequent-encounter codes like this one. Book a demo to see how Pabau keeps orthopedic and therapy claims accurate from note to payment.

Continue your research

Need to understand clearinghouse claim validation? Medical claims clearinghouse overview explains how electronic claim routing and validation work before payer adjudication.

Managing claim denials across a therapy practice? Electronic remittance advice guide covers how to read 835 ERA files to identify denial reason codes on fracture follow-up claims.

Billing orthopedic follow-up visits under Medicare? Revenue cycle management for healthcare practices covers the end-to-end billing process from documentation to payment posting.

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