ICD-10 Code S52.133S: Displaced radius neck fracture (sequela)

Key takeaways

S52.133S is a valid, billable ICD-10-CM code for FY2026, effective October 1, 2025.

It reports a displaced fracture of the neck of unspecified radius, sequela.

The 7th character S marks a late effect of a healed fracture. D covers follow-up during active healing, and A covers the first treatment visit.

The most common errors are using D for a late effect, and defaulting to unspecified laterality when the record names a side.

Practice management software like Pabau keeps the original fracture record and the current note in one place. That lets coders confirm displacement, laterality, and healing status before the claim goes out.

ICD-10 Code S52.133S is a valid, billable code for a displaced fracture of the neck of unspecified radius, sequela. Use it when a patient presents for a late effect of a radial neck fracture that has already healed. Residual stiffness, malunion, and chronic elbow pain are the typical reasons for the visit.

The 7th character S is what separates this code from S52.133A and S52.133D. Sports medicine practices see the most denials when they mix those three up on post-fracture follow-ups.

This guide covers the billable status of S52.133S and how to apply the 7th character. It maps the code against the rest of the S52.13x family, then sets out the supporting documentation and the errors that trigger denials.

ICD-10 Code S52.133S: Definition and billable status

ICD-10 Code S52.133S is a valid, billable ICD-10-CM diagnosis code for the FY2026 edition. Its full clinical description is Displaced fracture of neck of unspecified radius, sequela. It became effective on October 1, 2025, under the annual update cycle maintained by the CDC’s ICD-10-CM classification.

This code reports an encounter driven by the direct late effect of a documented displaced radial neck fracture. The fracture has healed, or the active healing phase is complete. Laterality is unspecified, meaning the record does not confirm whether the right or left radius was involved.

Code details at a glance

Use the table below as a quick reference when documenting or submitting this code. All fields reflect the FY2026 ICD-10-CM edition.

Understanding the 7th character S: sequela

The 7th character is the most misapplied element in fracture coding. For codes in the S52 category, it defines the encounter type. It tells the payer why the patient is presenting today, not what happened to them originally.

The ICD-10-CM Official Guidelines for FY2026, published by CMS, define sequela as the late effect of a previous injury. The injury itself is resolved, but a residual condition persists as a direct consequence of it.

Common sequelae after a displaced radial neck fracture include post-traumatic stiffness, malunion, chronic pain, reduced forearm rotation, and nerve compression.

The table below shows the three 7th characters that coders confuse most often in the S52.133 code family.

Subsequent encounter (D) covers care while the fracture is still healing. Sequela (S) covers care after it has healed. The two are not interchangeable. If a patient returns 14 months later with persistent stiffness and imaging confirms union, use S52.133S.

The same encounter-type characters run through the whole injury chapter, as S43.139D shows. The exercise is the same every time. Read the record, then match the encounter type to it.

For physical therapy practices treating patients through post-fracture rehabilitation, this distinction decides whether a claim is accepted.

S52.133S vs related codes: Choosing the right code

The S52.133 family covers displaced fractures of the radial neck with unspecified laterality. When the record documents a side, use the more specific laterality variant. The table below maps the S52.13x family so you can pick the right code.

Laterality specificity matters. ICD-10-CM guidelines require the most specific code the documentation supports. If the operative report, imaging, or clinical note states right radius, use S52.131S. Defaulting to the unspecified code when laterality is documented is an error that some payers flag on audit.

Unspecified-site codes elsewhere in the injury chapter draw the same scrutiny, S43.303A among them. Encourage clinicians to record laterality in every fracture note. Structured patient record systems that prompt for laterality at the point of documentation cut this error sharply.

Clinical description: displaced fracture of the neck of the radius

The neck of the radius is the narrowed segment just distal to the radial head. Fractures here usually follow a fall on an outstretched hand, known as the FOOSH mechanism, or a direct valgus stress to the elbow. They are most common in children but occur at every age.

A displaced fracture means the fragments have moved out of normal anatomical alignment. Displacement drives both surgical decision-making and code selection. Displaced and nondisplaced fractures of the same site use different codes.

Sequelae that generate sequela-encounter visits for radial neck fractures include:

• Reduced forearm rotation from periarticular fibrosis or malunion
• Chronic lateral elbow pain at the radiocapitellar joint
• Post-traumatic osteoarthritis of the elbow
• Radial head osteonecrosis, a rare but recognized late complication
• Heterotopic ossification limiting range of motion
• Ulnar or posterior interosseous nerve irritation secondary to malunion

These presentations are the clinical justification for S52.133S. The encounter treats the sequela, not the original fracture. Reduced supination can also come from distal biceps pathology. A bicep tear test helps rule that out before the deficit is attributed to the fracture.

Documentation requirements for a sequela encounter

The clinical record must support every element of the code. For S52.133S, the documentation has to establish four facts:

1. Fracture was displaced. The original injury record must document displacement, whether that is the ED note, the imaging report, or the operative note. If displacement was never recorded, a nondisplaced code variant applies.
2. Site is neck of the radius. The location must be specified as the radial neck, meaning the proximal radius or subcapital region. A radial head fracture is a different site and a different code family.
3. Laterality is unspecified. The encounter record should note that laterality was not documented or confirmed. If an earlier record has it, use S52.131S or S52.132S instead.
4. Current encounter is for sequela. The note must state that the patient presents for a direct late effect of the healed fracture. Notes describing active fracture healing or monitoring do not support 7th character S.

Under Section I.C.19 of the ICD-10-CM guidelines, the sequela code is sequenced first, followed by a code for the manifestation being treated. That second code names the residual condition. Examples include M84.33x for a stress fracture of the ulna and radius, or M25.32x for other elbow instability.

This sequencing rule is a frequent cause of claim rejection. Claims management workflows that validate code pairing against ICD-10 sequencing rules flag these errors before submission.

Common coding errors to avoid

Fracture sequela coding generates a disproportionate share of orthopedic claim denials. Most errors fall into four categories.

Practices using AI-assisted clinical documentation can cut the first category by structuring notes to state the fracture’s healing status outright.

A note reading “presenting for chronic elbow stiffness following healed radial neck fracture from 18 months prior” leaves no ambiguity. A note reading “follow-up, radial neck fracture” leaves the coder guessing between D and S.

Parent code and code hierarchy

Understanding the hierarchy above S52.133S helps coders navigate related codes and see the classification logic. The AAPC Codify ICD-10-CM reference presents it in full, and the structure below is condensed for practical use.

S52.13 covers only displaced fractures of the radial neck. Nondisplaced fractures belong to S52.14x, and radial head fractures belong to S52.10x through S52.12x. Mixing up radial head and radial neck fractures breaks both clinical accuracy and coding specificity.

How Pabau supports accurate fracture sequela coding

Sequela coding errors persist because the original encounter and the current encounter often live in different systems. More often, the coder only has the current note and has to reconstruct the encounter history from incomplete records.

Orthopedic and sports medicine practices need the whole patient timeline in one record. That means the original injury, imaging reports, surgical notes, aftercare visits, and today’s encounter.

When a patient returns 14 months later with elbow stiffness, the coder can see the full sequence. S52.133A was filed first, D encounters followed, and imaging confirmed union. That chain makes the sequela encounter type unambiguous.

Pabau’s digital clinical forms let practices build documentation templates around what fracture coding actually needs. That is displacement status, laterality, anatomical site, and healing phase.

Automated workflows can flag an encounter where healing status is missing, prompting the clinician to add it before the note is finalized. The prompt fires on the specific clinical context rather than a blanket checkbox. For practices running end-to-end practice operations at high orthopedic volume, that specificity lowers denial rates on fracture sequela codes.

Reduce coding errors with smarter documentation

Pabau's claims management tools and Pabau Scribe help orthopedic practices document encounters accurately. That supports correct ICD-10 code selection at the point of care.

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Conclusion

Sequela coding rewards practices that keep good records. S52.133S is easy to assign correctly when the original fracture note, the imaging, and today’s presentation all sit in front of you. It is guesswork when they do not.

So the fix sits upstream of the coder. Build the prompts for displacement, laterality, and healing status into the clinical note, and the right 7th character falls out of the documentation. Leave them out and you keep paying for it in denials.

Pabau’s claims management tools build those checks into the workflow your clinicians already use. Book a demo to see how those checks work on a fracture sequela claim.

Continue your research

Billing the surgical side of a fracture repair? 20902 covers bone graft coding when reconstruction follows the original injury.

Treating a fracture that is slow to heal? 20979 covers noninvasive ultrasound stimulation of bone, including how to document it.

Want a note format that records encounter type? SOAP progress notes template gives you a structure that captures healing status alongside the assessment.

Frequently asked questions