ICD-10 code S52.242J: Nondisplaced radius shaft fracture with nonunion

Key Takeaways

ICD-10 code S52.242J describes a nondisplaced fracture of the shaft of the radius, left arm, on a subsequent encounter for an open fracture type I or II with nonunion.

The 7th character J means the fracture has failed to heal (nonunion) and the patient is beyond the initial treatment phase.

Open fracture types I and II per the Gustilo-Anderson classification have lower contamination risk than type III; correct type documentation drives correct 7th character selection.

Pabau’s claims management software supports accurate ICD-10 diagnosis code capture and pairing with CPT procedure codes at the point of billing.

Most fracture billing errors happen not at the code level but at the encounter level. Coders select the right anatomical code and then apply the wrong 7th character, turning a clean claim into a denial. ICD-10-CM diagnostic coding rewards precision, and the S52.242J code is a clear example of why every character matters.

ICD-10 code S52.242J is the diagnosis code for a nondisplaced fracture of the shaft of the radius, left arm, on a subsequent encounter for an open fracture type I or II with nonunion. Every part of that description is encoded in the seven characters of the code. Understanding each character is the fastest way to use it correctly and defend it on audit.

This code is billable and valid for reimbursement submission under the current ICD-10-CM fiscal year tabular list. Verify the current status each October when CMS releases annual updates via the CMS ICD-10 codes page.

S52.242J code details at a glance

The table below provides the structured quick-reference data coders and billers need before submitting a claim with ICD-10 code S52.242J.

Breaking down ICD-10 code S52.242J character by character

Each character in the ICD-10-CM alphanumeric string carries a specific clinical meaning. Read S52.242J from left to right and the full clinical picture emerges.

The decimal point is a formatting convention, not a clinical character. The code is always written S52.242J in documentation, but payers accept the numeric string without the decimal in electronic claim formats. When in doubt, follow your clearinghouse’s formatting requirements.

Understanding the 7th character ‘J’: Subsequent encounter with nonunion

The 7th character is where most fracture coding errors occur. For subsequent encounter coding, the character must match both the fracture type and the healing status at the time of the visit.

The full set of 7th characters for open forearm fractures in the S52 category is:

Nonunion (J) vs. malunion (P): these are distinct clinical findings. Nonunion means the fracture ends have failed to bridge with bone. Malunion means healing has occurred but in an abnormal position. Both require specific documentation from the treating clinician before the coder can select the correct character.

Sequela (S) vs. subsequent encounter (J): a subsequent encounter covers ongoing active or monitoring care for the fracture itself. Sequela applies when the patient presents with a condition that is a consequence of a healed fracture, such as post-fracture wrist stiffness. Do not use S when the fracture is still the primary clinical concern.

Open fracture classification: Types I and II explained

The Gustilo-Anderson classification system is the standard reference for grading open fractures. ICD-10-CM maps directly to this classification when assigning 7th characters for open fractures. Getting the type wrong creates a code mismatch with the operative or clinical notes, which triggers medical necessity reviews.

S52.242J applies only to type I or type II wounds. If the clinical record documents a type IIIA, IIIB, or IIIC wound, the correct 7th character shifts to H (subsequent encounter, open type IIIA, IIIB, or IIIC, with nonunion). Using J for a type III wound is a coding error that may result in claim denial or audit recoupment.

Clinical presentation: Distal radius shaft fracture, left arm

Radial shaft fractures are most commonly the result of high-energy trauma – motor vehicle accidents, falls from height, or direct blows to the forearm. In sports medicine and sports medicine practice, they also arise from contact sports injuries and falls onto an outstretched hand.

A patient presenting at a subsequent encounter for an open radial shaft fracture with nonunion has typically been in care for some time. Characteristic findings at this stage include:

• Persistent pain or tenderness at the fracture site beyond the expected healing window
• Imaging evidence (X-ray or CT) showing absence of bridging callus
• Possible hardware failure if the fracture was initially treated with internal fixation
• Functional limitation of forearm rotation (pronation and supination) or wrist extension
• History of open wound at the time of original injury, classified as type I or type II

The nondisplaced designation means the fracture fragments have not significantly moved from their anatomical position. In an open fracture setting this matters because nondisplaced fractures sometimes still fail to unite due to soft tissue disruption, infection risk, or compromised vascular supply at the fracture site, all of which are more common after open injury.

ICD-10-CM coding guidelines for fracture nonunion

Per the ICD-10-CM Official Guidelines for Coding and Reporting (Section I.C.19.c), the 7th character for fracture codes must reflect the encounter type, not the original fracture classification. A patient who was initially treated for the same fracture at a different facility, and is now presenting to your practice for ongoing nonunion management, still receives a subsequent encounter character, because active treatment at the initial encounter is no longer occurring. The ICD-10 coding framework consistently treats the episode of care as the determining factor.

Key documentation requirements to support S52.242J:

• Clinical notes must state or clearly imply nonunion (not just “delayed healing” unless equivalent meaning is clear)
• The original wound classification as type I or II must be documented in the medical record
• Imaging supporting the nonunion finding (typically X-ray showing no bridging callus after the expected timeframe) must be present
• Laterality must be confirmed as the left arm in the clinical note or radiology report

Payers may request supporting documentation if this code appears on a claim without a corresponding operative note or imaging order. Capturing these details in digital patient intake forms and structured clinical notes at each visit reduces audit exposure. Good physiotherapy compliance requirements guidance also covers documentation standards for fracture-related encounters.

Related ICD-10 codes: Wrist fracture and radius shaft variants

S52.242J is one code in a large family of fracture codes. The table below covers the parent code, sibling encounter characters, and closely related wrist fracture ICD-10 codes that coders frequently reference alongside it. For a searchable reference, the AAPC Codify ICD-10-CM lookup is a reliable commercial tool.

Commonly paired CPT procedure codes

S52.242J appears on claims for subsequent-encounter management of an open radius shaft fracture with nonunion. The CPT codes below are commonly paired with this diagnosis. Payers check for medical necessity alignment between the diagnosis code and the procedure performed, so the selected CPT must reflect what actually happened at the visit. Using Pabau’s claims management software helps practices capture both the diagnosis and procedure codes consistently at the point of documentation.

CPT pairings are not prescriptive; specific LCD (Local Coverage Determination) and NCD (National Coverage Determination) policies govern which procedures Medicare and Medicaid will reimburse for a given diagnosis. Always verify payer-specific policies before submitting.

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Using S52.242J in physical therapy and rehabilitation billing

Physical therapists and occupational therapists treating patients with a radius shaft fracture nonunion regularly bill with subsequent encounter codes. The distinction that matters most in physical therapy practice management is whether the PT visit constitutes a subsequent encounter (7th character J) or represents a sequela visit (7th character S).

Use S52.242J when:

• The patient is still under active orthopaedic or rehabilitation care specifically for the fracture nonunion
• The treating physician has not declared the fracture healed or resolved
• Rehabilitation goals are directly tied to the fracture and nonunion (restoring forearm rotation, wrist strength, grip)
• The referring physician’s order references the original fracture diagnosis

Switch to sequela (S52.242S) when:

• The fracture itself has resolved but the patient presents with a condition resulting from it (chronic pain, limited range of motion classified as a separate condition, post-traumatic arthritis)
• The primary care focus has shifted from the fracture to its downstream consequences

Medicare Part B and most commercial payers accept subsequent encounter fracture codes as primary diagnoses for outpatient rehabilitation claims, provided the medical record supports ongoing active treatment. Some payers require a physician’s order or care plan renewal after 30 days. For practices managing high volumes of post-fracture rehab patients, reviewing physical therapy clinic requirements in your state ensures billing compliance aligns with both payer expectations and scope of practice rules.

Conclusion

Fracture nonunion coding has a narrow margin for error. The 7th character J in S52.242J depends on three concurrent facts documented in the clinical record: the fracture is on the left radius shaft, the original wound was classified as type I or II, and the fracture has not united. One missing piece and the claim lands in a medical review queue.

Practices that document encounter type, fracture type, laterality, and healing status consistently at every visit avoid most of these denials without additional effort. Pabau’s practice management software supports structured clinical note capture and diagnosis code entry in a single workflow, so the documentation that defends the billing is built into the visit rather than reconstructed after the fact. To see how it works in a real fracture care or rehabilitation practice, book a demo.

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