ICD code S92.155P – Nondisplaced left talus avulsion fracture with malunion

Key takeaways

S92.155P codes a nondisplaced avulsion (chip) fracture of the left talus at a subsequent encounter, after the fracture has healed with malunion.

The 7th character P means subsequent encounter for fracture with malunion, while S92.155S is the separate sequela code.

A malunion encounter takes one code, because S92.155P already describes both the fracture and the faulty healing.

The most common errors are the wrong side, the wrong bone, and a P assigned without the word malunion in the provider’s note.

Pabau’s claims management software validates each claim for missing or invalid details before it reaches the clearinghouse.

What is ICD-10 Code S92.155P?

ICD-10 Code S92.155P is the billable ICD-10-CM code for a nondisplaced avulsion fracture (chip fracture) of the left talus, subsequent encounter for fracture with malunion. Use it when the patient returns after the initial fracture care and the provider documents that the fracture healed in a faulty position.

The code carries four facts at once. The bone is the talus, the fracture is an avulsion, the fragment is nondisplaced, and the side is left. The 7th character P then says the visit is follow-up care for a fracture that united with malunion.

The code sits in category S92, fracture of foot and toe, except ankle, within the injury chapter of ICD-10-CM. Subcategory S92.1 covers the talus, and S92.15 is reserved for avulsion fractures of that bone. The CMS ICD-10-CM code set lists six S92.15 codes, split by displacement and side.

Clinical overview: Nondisplaced avulsion fracture of the talus

An avulsion fracture of the talus happens when a ligament or joint capsule pulls a small piece of bone off the talus. The talus is the ankle bone that sits between the tibia, the fibula and the calcaneus. In older texts it is called the astragalus.

These chip fractures usually follow an inversion injury, the same twisting motion that causes an ankle sprain. The fragment is small and stays in place. That makes the injury easy to miss on a first X-ray, so it is often treated as a sprain at first.

• Common mechanisms: Rolling the ankle inward, a missed step, or a sports landing on an uneven surface
• Typical symptoms: Pain and swelling over the front or side of the ankle, bruising, and pain when bearing weight
• Imaging confirmation: X-ray of the ankle or foot, with CT when the fragment is hard to see
• Malunion: The fracture heals, but the fragment unites out of its normal position, which can cause pain, catching or reduced motion

“Nondisplaced” describes the fracture when it was first diagnosed. A fracture that started nondisplaced keeps a nondisplaced code at every later encounter, even if it heals with malunion. The displaced versions, S92.151 to S92.153, are only correct when the provider documented displacement.

Understanding the 7th character ‘P’ in S92.155P

The 7th character P means subsequent encounter for fracture with malunion. Under the ICD-10-CM Official Guidelines, section I.C.19.c.1, care for a malunion is reported with the malunion 7th character for subsequent care.

Category S92 uses seven 7th characters. Each one tells the payer where the patient is in the course of the fracture.

P and K describe opposite outcomes. With K the bone has not united, and with P it has united in the wrong position. D covers normal healing, so a provider note must state malunion before D changes to P.

P and S are also different encounters. P keeps the focus on the malunited fracture itself. S applies once the fracture has healed and the visit treats a separate residual condition, such as post-traumatic arthritis. The chart below sets out the three questions in the order a coder should ask them.

S92.15 code family: Laterality and displacement

Subcategory S92.15 splits talar avulsion fractures by displacement and side. Choosing the wrong side or the wrong displacement is one of the fastest ways to a denial with this family.

The ICD-10-CM guidelines ask for the most specific code the record supports. When the imaging report or the clinical note names the left ankle, the unspecified code S92.156P is incorrect and creates audit risk. Workers’ compensation carriers also compare the side against the original injury report.

Keep the bone straight as well. An avulsion fracture of the calcaneus, the heel bone, is coded in subcategory S92.03, not S92.15. Check the original imaging report for the bone and the fracture type before you assign any S92.155 code.

Documentation requirements for S92.155P

Documentation for ICD-10 Code S92.155P has to support five elements. If one is missing, the payer can deny the claim or ask for more records.

• Bone and fracture type: An avulsion or chip fracture of the talus, with the original diagnosis date or encounter reference
• Displacement: The fracture was nondisplaced when it was diagnosed
• Laterality: The left ankle or left talus, stated in the clinical note and the imaging report
• Malunion: A provider statement that the fracture has healed in a faulty position, ideally supported by imaging
• Reason for the visit: What is being done for the malunion today, such as evaluation, bracing, therapy or surgical correction

How to code a malunion encounter

A malunion encounter needs one diagnosis code. S92.155P already tells the payer about the fracture and the faulty healing, so ICD-10-CM has no separate malunion code to add. Report P for every subsequent encounter that treats the malunion, including surgical correction.

The two-code sequela rule in guideline I.B.10 covers the 7th character S, not P. With S, the residual condition is coded first and S92.155S second. Use it only when the fracture healed and the visit treats a different late effect.

Here is how the code choice changes across one patient’s course of care:

Each row is a separate claim, so the 7th character is re-checked at every visit in the medical billing cycle.

Common codes confused with S92.155P

Several coding errors cluster around S92.155P. Each one follows a pattern that payer edits and auditors are built to catch.

Payer requirements and claim denial prevention for S92.155P

Malunion claims get more payer scrutiny than routine follow-up claims. The payer has to see why the patient needs further care for a fracture that has already united.

Maintaining medical billing compliance for these encounters means keeping the original fracture record easy to find. Payers often request the first imaging report during review, and a missing report is a common reason for denial.

• Commercial insurers: Expect clinical notes that document the malunion and the reason further treatment is needed
• Medicare: Local Coverage Determinations (LCDs) govern services such as physical therapy and orthotics billed with S92.155P, so check the LCD before you submit therapy codes
• Workers’ compensation: Carriers want the original injury date and claim number on every follow-up claim, and the rules vary by state

Practices that submit S92.155P electronically through Claim.MD can confirm coverage before the visit. The Claim.MD clearinghouse runs real-time eligibility checks with over 400 payers and checks the claim structure before it reaches the carrier.

Common denial reasons for S92.155P

Most S92.155P denials follow six patterns. Recognizing them before submission is easier than appealing afterward, and effective denial management in healthcare starts there.

1. Laterality mismatch: The note or imaging names the right ankle, but S92.155P (left) is billed
2. Malunion not documented: P is billed, but the provider’s note describes routine healing
3. Wrong bone: The record describes a calcaneus or other foot fracture, not the talus
4. Displacement mismatch: The original imaging describes a displaced fragment, which needs S92.152P
5. Sequela coded as P: The fracture healed normally and the visit treats a late effect, which needs S92.155S and a code for that condition
6. Invalid code year: The date of service falls outside the code set year you used, so check codes each October against the CDC’s ICD-10-CM tool

CPT codes commonly billed with S92.155P

S92.155P pairs with procedure codes for the evaluation and treatment of the malunion. Linking each CPT code to S92.155P on the claim is part of submitting a clean claim.

Check that each therapy line on the claim points to S92.155P, from the evaluation codes through 97110 exercise sessions. When a therapy claim is denied, the electronic remittance advice usually names the diagnosis pointer or documentation problem.

For extra code validation, the AAPC Codify ICD-10-CM lookup and Check ICD-10 are useful reference tools.

How claims management software prevents S92.155P coding errors

Most S92.155P errors start with a manual step. A biller copies the side from the wrong note, keeps the D code after the provider documents malunion, or leaves a diagnosis pointer blank.

In Pabau’s practice management system, claims management software comes with every subscription. Claims are pre-filled from the invoice, and claim validation scrubs each one for missing or invalid details before it leaves Pabau. A flagged claim links straight to the field that needs correcting.

In the US, Pabau submits CMS-1500 claims through Claim.MD and returns electronic remittance advice to the patient’s invoice. Your billing team sees which claims are paid, pending or denied, and why, without logging in to a separate portal.

Catch malunion coding errors before submission

Pabau’s claim validation checks each claim for missing or invalid details before it leaves Pabau. Your team fixes laterality and code errors before a payer denies the claim.

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Conclusion

S92.155P is a narrow code. It is correct only for a left talus, a chip fracture that started nondisplaced, and a follow-up visit where the provider has documented malunion. Get any of those wrong and the claim describes a different patient.

Before you submit, read the provider’s note for the word malunion and confirm the side on the imaging report. If the fracture healed normally and the visit treats a late effect, switch to S92.155S instead.

Book a demo to see how Pabau validates fracture claims before they reach the payer.

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