ICD code S72.113K – Displaced greater trochanter fracture of unspecified femur

Key takeaways

S72.113K describes a displaced greater trochanter fracture of an unspecified femur at a subsequent encounter, where the closed fracture has failed to unite.

Seventh character K requires imaging evidence of nonunion, such as an X-ray or CT report. Time elapsed or visit count alone never justifies K.

S72.113K is the wrong code when the record names the side. Use S72.111K for the right femur or S72.112K for the left.

When no record documents laterality, query the provider before falling back on the unspecified-side code.

Pabau’s claims management software sends fracture nonunion claims through Claim.MD, which checks them for errors before they reach the payer.

ICD-10 Code S72.113K: Definition and billable status

ICD-10 Code S72.113K is a billable ICD-10-CM diagnosis code, valid for FY 2027 claims, according to the CDC/NCHS ICD-10-CM official code tool. The official descriptor is: Displaced fracture of greater trochanter of unspecified femur, subsequent encounter for closed fracture with nonunion.

The code reports a closed greater trochanter fracture that has failed to unite on a femur whose side the record does not name. When the documentation says right or left, a lateralized code replaces it.

Code structure: Breaking down S72.113K segment by segment

S72.113K encodes five clinical facts in a single alphanumeric string. Each segment narrows the diagnosis from the fracture-of-femur category down to the anatomy, side, displacement status, and healing outcome. For S72.113K, the side segment reads “unspecified,” and that segment is the easiest one to misread.

The sixth character in S72.113 encodes displacement and laterality together. Displaced fractures use 1 for the right femur, 2 for the left, and 3 for an unspecified side. Nondisplaced fractures follow the same pattern with 4 (right), 5 (left), and 6 (unspecified).

So a displaced right nonunion is S72.111K, and a displaced left nonunion is S72.112K. Reading the 3 as “left” turns a lateralized claim into an unspecified one. Payers can question an unspecified-side code when the record clearly names the side.

Seventh character K: Subsequent encounter with nonunion explained

Seventh character K means the closed fracture has not healed at a subsequent encounter. Coders can assign it only when imaging or a provider note confirms the fragments have failed to unite. Section I.C.19.c of the ICD-10-CM Official Guidelines for Coding and Reporting covers the fracture seventh characters, nonunion included.

S72.113 takes sixteen seventh characters. They split along three lines: encounter type, healing status, and whether the fracture was closed or open. K is the closed-fracture nonunion character, so an open fracture that fails to unite codes to M or N instead.

The D-versus-K choice comes up at almost every orthopedic follow-up. D applies when the patient is progressing through expected healing, such as a routine six-week post-operative check.

K applies only when follow-up imaging shows the fracture line persists or callus formation is absent or insufficient. A treating physician who documents nonunion supports K as well. Selecting K for a straightforward follow-up without that evidence is incorrect and will likely trigger a medical necessity review.

K versus P matters just as much. Nonunion (K) means the bone has not healed. Malunion (P) means it healed in a malaligned or otherwise abnormal position.

The two findings call for different documentation and often different treatment. Coding K when the record documents malunion, or P when it documents nonunion, is a clinical accuracy error that payers and auditors flag.

Open versus closed matters too. The guidelines code a fracture not documented as open or closed as closed, which keeps K the default nonunion character for this code.

S72.113K vs similar codes: Laterality, displacement, and healing status

Nine codes sit closest to S72.113K in the S72.11 family. Coders tell them apart by three variables: side, displacement status, and seventh character. Laterality deserves the closest look, because S72.113K is the code for an unspecified side.

Four rules prevent the most common mix-ups:

• Code the documented side. If the operative report or imaging names the right or left femur, S72.113K is a specificity error. Use S72.111K for the right side or S72.112K for the left.
• Query before you fall back. The guidelines let you take laterality from other clinicians’ documentation, such as a radiology report. Use S72.113K only when no record names the side and a provider query cannot confirm it.
• Displacement comes from the initial imaging. It does not change at later encounters. A fracture not documented as displaced or nondisplaced codes to displaced.
• K never applies to active treatment. The initial encounter for a closed fracture codes to S72.113A, or to the lateralized A code when the side is known. Using K at that visit is a categorical error that payers catch quickly.

The decision path below runs those checks in order, from the nonunion finding to the side.

Documentation requirements for S72.113K claims

Six documentation elements must be present in the medical record before a coder assigns S72.113K. Missing any one creates the conditions for denial or a medical necessity audit.

• Imaging confirming nonunion: X-ray or CT findings must show absent bridging callus or a persistent fracture line when healing would normally be expected. The imaging report must be in the record and dated to the encounter or within a clinically appropriate window.
• Provider attestation: The treating orthopedic surgeon or physician must state in the note that the fracture has not healed. A line like “fracture nonunion confirmed on imaging” supports K. A note that the patient is “still symptomatic” or in pain does not.
• Laterality check: S72.113K fits only when no clinician’s documentation identifies the left or right femur. If imaging or an operative note names the side, code S72.111K (right) or S72.112K (left). If nobody documented it, query the provider before coding. Records that contradict each other on side need a query too.
• Displacement status: The initial fracture must have been displaced, or undocumented, since undocumented status defaults to displaced. If the original imaging showed a nondisplaced fracture, use S72.114K (right), S72.115K (left), or S72.116K (unspecified side).
• Mechanism of injury (for external cause coding): The mechanism should be documented to support the external cause code. Falls are the predominant mechanism for greater trochanter fractures in older adults.
• Encounter type: The record must reflect a subsequent encounter, meaning active treatment of the original injury is complete. A visit that is still active treatment codes to an A character instead.

External cause codes to report alongside S72.113K

ICD-10-CM guidelines encourage external cause code reporting with injury codes, and many payers require it for orthopedic fracture claims. For greater trochanter fractures, falls are the most clinically common mechanism, according to the American Academy of Orthopaedic Surgeons. The external cause code documents how the injury occurred.

It is reported as a secondary diagnosis alongside S72.113K. An orthopedic EMR that prompts for the mechanism at the point of documentation keeps these secondary codes from being dropped at billing.

Match the seventh character of the external cause code to the encounter type. At a subsequent visit for nonunion, the W-code should carry seventh character D (subsequent encounter), not A (initial). Reporting W19.XXXA alongside S72.113K creates an encounter-type mismatch that some payer edits will flag.

Payer requirements and prior authorization for S72.113K

Payer requirements for fracture nonunion claims vary by insurer, plan type, and state. These are general patterns, so coders and billing teams should verify individual payer guidelines before submission. Per CMS ICD-10-CM coding and billing guidance, S72.113K is accepted as a valid Medicare diagnosis code when supported by documentation.

• Medicare: Medical necessity documentation for nonunion treatment is required. Surgical intervention for nonunion (such as bone grafting) may trigger a Local Coverage Determination (LCD) review. The applicable LCD varies by Medicare Administrative Contractor (MAC) jurisdiction, so check your MAC’s policy for hip fracture nonunion procedures. Medicare data on fracture claims is searchable via ResDAC’s ICD codes in Medicare files resource.
• Commercial payers: Prior authorization is commonly required when S72.113K is paired with surgical CPT codes for nonunion repair (such as bone graft procedures). The nonunion diagnosis supports medical necessity for the intervention. Submit documentation linking the imaging finding to the proposed procedure with the PA request.
• Medicaid: Requirements vary significantly by state. Some state Medicaid programs require additional review for fracture nonunion procedures. Verify with the applicable state plan.

Common denial reasons for fracture nonunion claims

S72.113K claims deny for predictable reasons. Most failures trace back to documentation that does not support the seventh character K, or to code selection errors in the S72.11 family.

Knowing the top denial patterns lets billing teams build prevention into the workflow instead of reacting after the remittance. Orthopedic denial management workflows start by finding which codes generate the most preventable rejections.

• K assigned without documented nonunion: The most frequent denial. The provider documented a follow-up visit, but imaging results were not in the record or the note described symptoms without stating nonunion. Fix: query the provider for a specific nonunion attestation tied to imaging findings before coding K.
• K used when D is correct: The fracture is healing normally, but K was chosen because the visit is the third or fourth follow-up. K reports healing status, so the visit count never decides it. Fix: review imaging interpretation in the record before selecting the seventh character.
• Unspecified side when laterality is documented: S72.113K reports an unspecified femur. Submitting it when imaging or the operative note names the side is a specificity error that payers can question or deny. Fix: check every record for laterality, then code S72.111K (right) or S72.112K (left).
• Missing external cause code: Some payers flag injury claims lacking an external cause code entirely. Fix: include the appropriate W-code at every fracture-related encounter, with the correct seventh character for the encounter type.
• Encounter type mismatch: Reporting S72.113A (initial encounter) for a visit where prior treatment is documented creates an encounter-type conflict. Fix: confirm prior treatment history before assigning seventh character A at any visit.

When denials do occur, referencing the applicable denial codes in medical billing shows what kind of rejection you are facing. It may be a claim edit, a medical necessity determination, or a documentation deficiency. Each one calls for a different appeal strategy.

How claims management software prevents S72.113K denials

Most S72.113K denials start before anyone opens the coding screen. The imaging report sits in one system and the provider note in another. The coder may never see the side and the nonunion finding together.

Pabau’s practice management software keeps clinical notes, attached imaging reports, and billing in one patient record. Coders can confirm laterality and the nonunion finding before choosing between S72.111K, S72.112K, and S72.113K.

From there, Pabau’s claims software for coders sends each claim through Claim.MD, its US clearinghouse partner. Pair it with a routine for submitting a clean claim, and documentation problems surface before the payer sees them.

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Pabau’s claims management software integrates with Claim.MD to validate ICD-10-CM codes, track fracture nonunion claims, and reduce denials before they happen.

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Conclusion

S72.113K is correct in a narrow set of cases. The fracture was displaced, the closed fracture has failed to unite on imaging, and no record names the side.

Treat the unspecified-side code as a last resort. Query the provider when laterality is missing, and switch to S72.111K or S72.112K once the side is documented. Pair that habit with a nonunion check on every K claim, and avoidable denials in this family become rare.

Book a demo to see how Pabau keeps fracture documentation and claims in one place, so coders can confirm side and healing status before submission.

Continue your research

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