ICD code S52.202H – Unspecified fracture of shaft of left ulna

Key takeaways

S52.202H means unspecified fracture of shaft of left ulna, subsequent encounter for open fracture type I or II with delayed healing

Character H needs three documented facts: a subsequent encounter, an original Gustilo-Anderson type I or II open wound, and delayed healing

Delayed healing takes character H. For that same type I or II wound, nonunion takes M and malunion takes Q

A type IIIA, IIIB, or IIIC wound with delayed healing takes character J, and a closed fracture with delayed healing takes G

Pabau’s claims management connects to the Claim.MD clearinghouse, so fracture aftercare claims move from the patient record to the payer without retyping

ICD-10 code S52.202H is billable at seven characters

S52.202H is a billable, specific ICD-10-CM diagnosis code. Its official descriptor reads: Unspecified fracture of shaft of left ulna, subsequent encounter for open fracture type I or II with delayed healing. The FY2026 edition took effect on October 1, 2025. It comes from the annual update maintained by the Centers for Medicare and Medicaid Services (CMS) and the National Center for Health Statistics.

The 7th character is what makes the code usable. S52.202 on its own is a non-billable parent code. A claim carrying it without a 7th character extension rejects before it reaches adjudication.

Every character in S52.202H carries one clinical fact

Each segment of the code narrows the diagnosis by one step. Misreading any one of them sends the claim out under the wrong code.

The hierarchy runs from the injury chapter (S00-T88) through the forearm category (S52) to the ulna shaft subcategory (S52.2). The 20 in S52.20 says the fracture pattern was never documented. Transverse, oblique, spiral, comminuted, and segmental patterns each have their own subcategory. If the operative note names a pattern, a more specific base code applies. As the AAPC ICD-10-CM code reference notes, the 7th character extension must always be appended to complete a code in this category.

The 7th character records the wound grade and the healing course

The 7th character on S52.202 encodes three facts at once. It carries the encounter type, the wound status at the original injury, and the healing outcome. All three have to be documented before you select a character, and the diagram below traces the only path that ends at H.

ICD-10-CM groups the Gustilo-Anderson grades into two buckets. Types I and II travel together, and types IIIA, IIIB, and IIIC travel together. That grouping is why character H covers two grades rather than one. The letters I, L, and O are never used, which is why the sequence jumps from H to J and from K to M.

Gustilo types I and II are the wounds character H covers

Character H applies only when the original wound was graded Gustilo-Anderson type I or II. That grade comes from the initial injury encounter, usually the emergency department record or the first operative report. If the wound was type IIIA, IIIB, or IIIC, delayed healing takes character J instead. Assigning H without documentation of the lower grade is a coding error, and payers audit for it.

The boundary that matters for this code sits between type II and type IIIA. It turns on the extent of soft tissue damage, not on wound length alone. When the operative note is ambiguous, ask the treating surgeon for an addendum before you assign H.

Delayed healing, nonunion, and malunion are three different characters

These three outcomes describe different things, and ICD-10-CM gives each one its own 7th character. Substituting one for another is among the most common fracture coding errors flagged in payer audits. The wound grade and the healing outcome together decide the letter.

The record has to say which outcome applies. Phrases such as slow to heal, delayed union, or not yet united support delayed healing, which is what character H records. A documented nonunion or malunion moves the claim to a different letter. That holds even when the visit looks identical.

When a subsequent encounter code applies

Subsequent encounter coding starts once active treatment of the fracture is complete. The patient is then in the healing or recovery phase. The ICD-10-CM Official Guidelines tie this to the phase of care, not to how many times the practice has seen the patient.

• Initial encounter (A, B, C): the patient is receiving active treatment for the fracture, whichever provider delivers it. A second surgeon operating on the same fracture still codes an initial encounter.
• Subsequent encounter (D through R): active treatment is complete. The patient is receiving aftercare, monitoring, or management of a healing complication. Routine follow-up visits, therapy encounters, and cast or hardware checks all sit here.
• Sequela (S): the fracture itself has resolved, and a late effect such as chronic stiffness is now the reason for the visit.

For S52.202H, active treatment has ended and the patient is in follow-up. The original wound was an open type I or II. Imaging and the provider note both point to union running behind schedule. If the surgeon takes the patient back to the operating room to promote union, that episode reverts to an initial encounter character.

How the 7th character changes as the fracture heals

One patient can move through five or six characters on the same code inside a year. The base code S52.202 never changes. Only the 7th character moves, and it moves with the documented phase of care. A single left ulna shaft fracture with a grade II open wound might run like this.

• Day of injury, wound debrided and the fracture fixed: S52.202B, initial encounter for open fracture type I or II.
• Six weeks out, callus on schedule: S52.202E, subsequent encounter with routine healing.
• Four months out, callus present but union behind schedule: S52.202H, subsequent encounter with delayed healing.
• Nine months out, no bridging callus and sclerotic ends: S52.202M, subsequent encounter with nonunion.
• Union achieved but the forearm is angulated: S52.202Q, subsequent encounter with malunion.
• Fracture resolved, chronic stiffness now the reason for the visit: S52.202S, sequela.

Character H is a stage, not a permanent label. Re-read the current imaging at every visit, because the same patient on the same code can need a different letter three months later.

Related ICD-10-CM codes for ulna shaft fractures

Working the neighboring codes prevents the usual laterality, wound-status, and healing-outcome mix-ups. The table below covers the codes most often confused with S52.202H.

Two neighbors account for most of the errors around H. S52.202G is the closed-fracture version of delayed healing, and S52.202J is the type III version. Confirm the original wound grade in the operative note before choosing between the three. Pabau’s ICD-10-CM code library carries the same breakdown for the neighboring forearm codes.

Approximate synonyms and clinical terminology

The ICD-10-CM index recognizes several alternate clinical phrasings that lead to S52.202H. Coders searching under any of these terms land on this code or its parent category.

• Left ulnar shaft fracture, subsequent encounter, delayed healing of a grade I or II open wound
• Slow-healing open fracture of the left ulna shaft, follow-up care
• Delayed union of an open left ulna shaft fracture, Gustilo type I or II
• Open left ulna shaft fracture, aftercare for delayed union
• Left forearm bone (ulna) shaft fracture, low-grade open wound, healing behind schedule

Notes using any of these phrasings map to S52.202H during chart abstraction. The wound grade still has to be confirmed as type I or II at the initial encounter. A clean audit trail links the follow-up code back to that original record.

Billing and reimbursement: submitting S52.202H

S52.202H is billable on a CMS-1500 claim or an 837P electronic transaction. The code carries no payment of its own. It establishes medical necessity for the service the visit actually delivered, which is why the pairing with the procedure code decides whether the claim pays.

Five things need to be in the record before the claim goes out.

• Original operative or emergency note: confirms the fracture was open and records the Gustilo-Anderson grade as I or II.
• Current imaging report: shows union progressing, but behind the expected interval for this fracture.
• Provider statement: says in words that healing is delayed or slower than expected.
• Encounter note: shows this visit is follow-up care rather than active treatment of the fracture.
• Laterality: names the left ulna, so the code and the record agree.

Pair S52.202H with the CPT code for the service delivered that day. A follow-up assessment usually bills an established patient evaluation and management code, such as 99213 or 99214. Fracture care codes carrying a global period do not fit, because active treatment is over. Radiographs taken and read in the office bill separately when the practice owns the equipment.

When a follow-up visit also dispenses a splint, the device code turns on what happened at the fitting rather than on the fracture code. HCPCS code L3924 covers a prefabricated orthosis handed over as manufactured, and modifying it at fitting moves the line to L3923.

For US practices, Pabau supports electronic claims through Claim.MD, a clearinghouse connected to thousands of US payers. It submits and tracks the claim using the record data the practice already holds. Eligibility checks and electronic remittance advice come back against the same patient. That matters on a fracture patient billed across half a dozen follow-up visits.

Five mistakes that get an S52.202H claim denied

• Coding malunion as H. Malunion on a type I or II open wound is character Q. Character H is delayed healing only.
• Carrying a type III grade forward. A IIIA, IIIB, or IIIC wound with delayed healing is character J, not H.
• Treating H as the closed-fracture option. A closed left ulna shaft fracture with delayed healing is character G.
• Using H during active treatment. Active care still takes an initial encounter character, even at the third visit.
• Leaving the pattern unspecified when the note names it. A documented transverse or comminuted fracture points to a more specific base code than S52.20.

Four of those five come down to one habit. Read the original injury documentation before you pick the 7th character, rather than coding from this month’s note alone. When one of these slips through, denial management is where the recovery starts.

Where Pabau keeps a fracture code consistent across every follow-up

A delayed-healing claim depends on records created months apart. The wound grade sits in an emergency department note from the day of injury. The evidence of slow union sits in this month’s imaging. In many practices those two documents live in different systems, so the coder rebuilds the story by hand at every visit.

Practice management software like Pabau keeps the whole fracture episode on one patient record. The original operative note, each follow-up note, and the imaging reports stay attached to the same timeline. When the coder opens this month’s visit, the original wound grade is a click away instead of a phone call to the hospital.

That same record feeds claims management without retyping. Pabau sends the encounter to the clearinghouse for submission and tracking, then files the payer’s remittance back against the same record. So when a delayed-healing claim returns with a denial code, the note that answers it is already in front of the biller.

Keep fracture aftercare claims clean across every follow-up

Pabau keeps the original injury note, each follow-up, and the claim on one patient record, and submits through Claim.MD for US practices. See how it handles a multi-visit fracture episode.

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Conclusion

Character H on S52.202 records one narrow scenario. The left ulna shaft fracture was open at grade I or II, active treatment has finished, and union is running behind schedule. Change any one of those facts and the character changes with it. A type III wound takes J. A closed fracture takes G. Nonunion takes M, and malunion takes Q.

The habit that prevents most denials on this code is simple. Read the original operative note before every follow-up claim, not just the imaging in front of you. Pabau keeps that note, the follow-up documentation, and the claim on one record, so fracture billing stops depending on memory. To see how it handles a multi-visit fracture episode, book a demo with the team.

Continue your research

Need to understand how clearinghouse claims submission works? Medical claims clearinghouse guide explains the end-to-end submission process from practice to payer.

Looking for denial reason code definitions? Denial codes in medical billing breaks down common CARC reason codes and how to respond to them.

Want to understand how 837P electronic files are structured? 837 file guide covers the transaction set used for electronic claim submission.

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