ICD code S72.135C – Nondisplaced left femur apophyseal fracture

Key takeaways

ICD-10 Code S72.135C is a billable code for a nondisplaced apophyseal fracture of the left femur at open fracture severity IIIA, IIIB, or IIIC.

The 7th character C marks the initial encounter for an open fracture graded IIIA, IIIB, or IIIC under the Gustilo-Anderson classification.

Subsequent encounters and sequelae for the same injury take different 7th characters, so the code moves as treatment moves.

The operative note must state laterality, displacement status, fracture site, open fracture grade, and encounter type before the code is reportable.

Practice management software like Pabau checks ICD-10 diagnosis codes against CPT procedure codes before a claim leaves the practice.

ICD-10 Code S72.135C: Definition and billable status

S72.135C is the billable ICD-10-CM code for a nondisplaced apophyseal fracture of the left femur. It applies to the initial encounter for an open fracture of type IIIA, IIIB, or IIIC. The code appears in the current FY2026 edition of ICD-10-CM and is valid for HIPAA-covered transactions.

The Centers for Medicare and Medicaid Services (CMS) maintains ICD-10-CM jointly with the National Center for Health Statistics (NCHS). Apophyseal fracture codes in the S72.13 subcategory are long-standing entries, so the FY2026 update did not introduce S72.135C.

What is a nondisplaced apophyseal fracture of the left femur?

A nondisplaced apophyseal fracture of the left femur is a break at an apophysis of the left femoral bone. The fragments stay in anatomical alignment, which is what nondisplaced means. An apophysis is a bony prominence where major muscle tendons attach.

On the femur that usually means the greater or lesser trochanter. The bone ends have not shifted, but the open wound classification in S72.135C still signals significant soft tissue injury.

An operative report that describes a nondisplaced apophyseal fracture does not support a displaced or shaft-level code. Choosing one anyway is a common reason orthopedic fracture claims get down-coded or denied.

• Nondisplaced: The fracture line is present, but the fragments keep their normal anatomical relationship.
• Apophyseal: The fracture sits at a bony prominence such as the greater or lesser trochanter, not the shaft or neck.
• Left femur: Laterality is an explicit code component, and right-side injuries take the S72.134x series instead.
• Open fracture: The bone communicates with the external environment, and the Gustilo-Anderson grade sets the 7th character.

Open fracture types IIIA, IIIB, and IIIC: The Gustilo-Anderson classification

The Gustilo-Anderson classification grades open fractures by wound size, soft tissue damage, and vascular injury. Gustilo and Anderson introduced it in 1976 and refined it in 1984. ICD-10-CM still references it for 7th character selection in open femur fractures. S72.135C covers the type III injuries, which involve large wounds, heavy contamination, and often periosteal stripping.

All three subtypes map to the same 7th character C for the initial encounter. The clinical distinction between them affects surgical planning and prognosis, but it does not change the ICD-10-CM code at this level.

Coders do not need to work out which subtype the surgeon documented. Any type IIIA, IIIB, or IIIC grade on an initial encounter maps to S72.135C.

ICD-10-CM 7th character rules for S72.135

The 7th character is required for every fracture code in the S72 category. It encodes the encounter type and, for open fractures, the Gustilo-Anderson grade. S72.135C uses character C, which is reserved for the initial encounter for open fracture type IIIA, IIIB, or IIIC.

The initial encounter character applies to every visit where the patient receives active fracture treatment. That covers more than the emergency department visit and the surgical admission.

Two questions decide the character. One is how the wound was documented, and the other is where the patient sits in the course of treatment. The grid below separates them.

Use character C only while the patient is receiving active fracture treatment. Once surgical stabilization is complete and follow-up visits focus on healing, the character shifts to F for routine healing or J for delayed healing.

Failing to update the 7th character at that transition is a common audit finding in orthopedic coding. Practices that track it through denial management can see which character errors cost them the most.

S72.135C code hierarchy and classification

The parent code tree runs from the chapter down to the billable code. Following it in order reduces selection errors among closely related S72 codes. The CDC and NCHS ICD-10-CM web tool displays the same hierarchy for each fiscal year edition.

The S72.13 subcategory covers apophyseal fractures of the femur. S72.131 and S72.132 are the displaced variants for the right and left femur. S72.134 and S72.135 are the nondisplaced pair, and the 7th character then sets the encounter and the wound type.

Related ICD-10-CM codes for femur fractures

S72.135C sits in a tightly grouped family of apophyseal and pertrochanteric femur fracture codes. Selecting the wrong sibling is the most common error in this category. The table below shows the codes most often confused with it, alongside the other encounter codes for the same injury.

The rest of the S00-T88 injury chapter follows the same pattern, and our ICD-10 diagnostic code library indexes those codes by category.

Associated CPT codes for open femur fracture treatment

S72.135C pairs with CPT procedure codes for surgical and non-surgical management of open femur fractures. The CPT code depends on the treatment method, whether that is internal fixation, external fixation, or non-operative stabilization.

The AAPC ICD-10-CM code reference provides crosswalk guidance for orthopedic fracture cases. A clearinghouse edit check catches a mismatched diagnosis-procedure pair before the claim reaches the payer.

This crosswalk is informational. Payers may apply their own medical necessity policies to these procedure codes, so confirm coverage before billing. A claim that pairs S72.135C with a closed-treatment code will draw scrutiny, because the diagnosis describes an open injury.

ICD-10-CM coding guidelines for fractures

Section I.C.19 of the official ICD-10-CM coding guidelines governs fracture coding across the S70-S79 hip and thigh injury block. These rules apply directly to S72.135C and are the primary reference for any coding dispute or audit response. Apply them consistently across every trauma encounter, not only the high-complexity open fractures.

• Active treatment vs. aftercare: Use character C for every visit that involves active fracture treatment, including surgery. Switch to a subsequent encounter character once active treatment ends.
• External cause codes: Add an external cause code from the V-Y block as a secondary code to identify the mechanism. Motor vehicle accidents (V series) and falls (W series) are the common ones. The injury code is always sequenced first.
• Laterality: ICD-10-CM requires laterality documentation, and S72.135C is exclusively for the left femur. Where the note is ambiguous, query the treating clinician rather than defaulting to an unspecified code.
• Gustilo grade from the operative report: The open fracture grade must come from the surgeon’s operative or emergency note. Do not assign type IIIA, IIIB, or IIIC from imaging alone.

The encounter-type character structure is consistent across Chapter 19 injury codes, so the logic carries over to other fracture types. Electronic remittance advice shows which 7th character errors generate the most rejections, so coder training can be aimed at the costly ones.

Documentation requirements for S72.135C

S72.135C cannot be assigned from incomplete documentation. Every component of the code description maps to a specific piece of clinical information that the operative or emergency note must supply. Missing any one element forces a less-specific code that may not support medical necessity for the CPT procedure.

• Laterality (left): The operative note must name the left femur. A report that says “femur” without laterality cannot support S72.135C.
• Displacement status (nondisplaced): The surgeon must document that the fragments are in anatomical alignment. “Minimally displaced” or “impacted” without further detail may need clarification.
• Fracture site (apophyseal): The note must identify the site as an apophysis. That usually means the greater or lesser trochanter, or the apophyseal region near the femoral head-neck junction.
• Open fracture grade (IIIA, IIIB, or IIIC): The Gustilo-Anderson grade must appear in the operative or emergency report. Wound size, soft tissue status, and vascular findings all support that grade.
• Encounter type (initial): Confirm this is a visit for active treatment. Subsequent encounters for the same fracture event use a different 7th character.

A pre-billing check on the operative report catches the missing element while the surgeon is still available to clarify it. Once the note is signed and the claim has gone out, the fix costs an appeal instead of a query.

How Pabau checks S72.135C before the claim leaves the practice

Most orthopedic practices find a 7th character error after the payer does. The coder assigns C, the claim goes out, and the rejection arrives weeks later. By then nobody can trace it back to a single line in the note.

Practice management software like Pabau runs that check before the claim is submitted. Pabau’s claims software for practices holds the ICD-10 and CPT catalogs in one place. A diagnosis-procedure pair that a payer will not accept is flagged at the point of entry.

Claims leave as 837P files through the Claim.MD clearinghouse, and eligibility responses and ERA remittances come back into the same record. For a trauma admission carrying several procedure codes against one diagnosis, that removes most of the manual reconciliation.

Catch open fracture coding errors before submission

Pabau validates ICD-10 diagnosis codes against CPT procedure codes and sends clean 837P claims through the Claim.MD clearinghouse. Fewer mismatches, fewer denials, and faster payment on orthopedic and trauma cases.

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Conclusion

S72.135C is a four-part code, and the operative note has to carry all four parts. Laterality, displacement, fracture site, and open fracture grade each need to be documented before the code is assignable.

Get one of them wrong and you land on a sibling code that no longer matches the procedure billed. The 7th character is the one piece that keeps moving. Build the C-to-F transition into your post-operative review rather than your denial log.

Book a demo to see how Pabau validates ICD-10 and CPT pairings before an orthopedic claim leaves your practice.

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