ICD code S72.145M – Nondisplaced intertrochanteric fracture of left femur with nonunion

Key takeaways

S72.145M codes a follow-up visit for a nondisplaced intertrochanteric fracture of the left femur that has gone on to nonunion.

The 7th character M means the original fracture was open, Gustilo type I or II, while closed fractures take K and type III takes N.

The code already names the left side, so a right-sided nonunion takes S72.144M and an undocumented side takes S72.146M.

The intertrochanteric region sits below the femoral neck, so femoral neck codes in S72.0- and neck procedures such as CPT 27236 do not fit.

Pabau, the practice software we build, checks each claim against payer rules before submission, so a wrong 7th character gets caught early.

ICD-10 Code S72.145M: Quick reference

ICD-10 Code S72.145M is the billable code for a follow-up visit when a nondisplaced intertrochanteric fracture of the left femur has gone on to nonunion. The original fracture was open, Gustilo type I or II, and the provider has documented that it failed to heal.

Verify current-year code validity using the CDC/NCHS ICD-10-CM web tool, which mirrors the official tabular list updated each October 1.

What does S72.145M mean? Breaking down each character

Like other ICD-10-CM codes, S72.145M packs five layers of clinical information into seven characters. Reading left to right:

The sixth character carries two facts at once. In the S72.14- family, 1 to 3 are displaced fractures and 4 to 6 are nondisplaced. Each set runs right, left, then unspecified, so a 5 means nondisplaced and left.

Nondisplaced means the bone fragments stayed in anatomical alignment at the time of injury. Nonunion is a later complication, where the provider documents that the fracture has stopped progressing toward healing.

Official guidelines code a fracture not documented as displaced or nondisplaced as displaced. Without the word nondisplaced in the record, the code becomes S72.142M.

Put together, three decisions in the record build the code: the fracture site, then displacement and side, then the original wound.

Intertrochanteric anatomy and why nonunion occurs

The intertrochanteric region is the stretch of the proximal femur between the greater trochanter and the lesser trochanter. It sits below the femoral neck and outside the hip joint capsule. That location is why ICD-10-CM files these fractures under S72.1, apart from the femoral neck codes in S72.0-.

Unlike the femoral neck, this region is mostly cancellous bone with a generous blood supply from the surrounding muscle attachments. Intertrochanteric fractures therefore usually heal, and nonunion is uncommon. When it does occur, the cause is more often mechanical than vascular.

Factors linked to intertrochanteric nonunion include:

• An unstable fracture pattern that loses position after fixation
• Fixation failure, such as lag screw cut-out through the femoral head or collapse into varus
• Infection, a particular risk after an open fracture
• Osteoporosis and poor bone quality, most often in older women
• Smoking, diabetes and chronic corticosteroid use, which slow bone healing

Open intertrochanteric fractures are rare, because thick muscle covers the hip. They usually follow high-energy trauma such as a road collision or a fall from height. An M code on an older patient’s low-energy fall therefore deserves a second look at the original fracture record.

Nonunion is defined as failure of fracture healing, confirmed by imaging or surgery. For the coder, that confirmation is not optional. It must appear in the record before S72.145M can be assigned.

Understanding the 7th character M: Open fracture type I or II with nonunion

The 7th character M marks a follow-up encounter for an open fracture, Gustilo type I or II, that has not united. Category S72 uses the full 16-value fracture extension:

Three characters cover nonunion, and the original wound decides between them. K covers a closed fracture, M an open type I or II fracture, and N an open type IIIA, IIIB, or IIIC fracture.

Gustilo type I and II wounds are smaller, with limited soft-tissue damage. Type III wounds involve extensive soft-tissue injury, and IIIC adds a vascular injury that needs repair.

ICD-10-CM guidelines set two defaults here. An open fracture with no documented Gustilo type takes M, the type I or II character. A fracture not documented as open or closed is coded as closed, so it takes K instead. Query the surgeon whenever the record could support N.

What S72.145M covers: Inclusions

S72.145M applies when all of the following are true at the time of the encounter:

• The patient has a previously diagnosed nondisplaced intertrochanteric fracture of the left femur
• The original fracture was open and documented as Gustilo type I or II, or as open with no type stated
• The visit comes after active treatment of the original fracture, including surgery to repair the nonunion
• Nonunion is confirmed by imaging (plain X-ray, CT, or MRI) or by surgical exploration
• The treating provider explicitly documents nonunion, not just “slow healing” or “fracture not healed”

Typical visits assigned this code include nonunion repair, bone grafting, revision of failed fixation, and office evaluations to manage an established nonunion.

What S72.145M does not cover: Excludes notes and coding boundaries

The S72 category carries Excludes1 and Excludes2 notes, and the chapter sets further boundaries that affect code assignment:

• Excludes1 (cannot code together): Traumatic amputation of hip and thigh (S78.-). When the encounter involves an amputation at hip or thigh level, S78.- applies and S72.145M is not reported with it.
• Excludes2 (may code together when both are present): Fracture of lower leg and ankle (S82.-) and fracture of foot (S92.-). Report them alongside S72.145M when the patient has those injuries too.
• Periprosthetic fractures: A fracture around a hip replacement is coded to periprosthetic fracture around internal prosthetic hip joint (M97.0-), not to S72.-.
• Pathological fractures: Fractures due to neoplasm (M84.5-), osteoporosis (M80.-), or other disease (M84.6-) are classified separately. S72.145M applies to traumatic fractures only.
• Failed hardware: A broken nail, plate, or screw is a mechanical complication of the internal fixation device, coded in T84.1-. Code it in addition when documented, and sequence by the reason for the visit.

Adjacent and commonly confused codes

The codes below are the closest neighbors of S72.145M and the ones most easily swapped in error. Use the AAPC Codify ICD-10-CM lookup to confirm full descriptors and any applicable notes.

Clinical documentation requirements for S72.145M

Nonunion fracture care draws close payer scrutiny, so denial management for these claims starts with the chart. Every element below must appear in the medical record before assigning ICD-10 Code S72.145M:

1. Original fracture diagnosis and date of injury. The record must establish when the fracture occurred and that it was an open, nondisplaced intertrochanteric fracture. Without that originating event, payers cannot verify the progression to nonunion.
2. Imaging confirming nonunion. A plain X-ray, CT scan, or MRI report should state that union has not occurred. “Fracture line still visible” is not enough on its own. The report should use the term nonunion or describe the absence of bridging callus.
3. Treating provider’s documentation of nonunion. The provider’s note must state that nonunion is the diagnosis driving this encounter. Coders cannot assign nonunion from imaging alone, because code assignment rests on provider documentation.
4. Site, side, and displacement. The record must name the intertrochanteric region, the left femur, and a nondisplaced pattern. If any one of the three changes, so does the code.
5. Open fracture type. Gustilo type I or II supports M, and type IIIA, IIIB, or IIIC supports N. An open fracture with no stated type defaults to M.
6. Current treatment plan. The note should outline how the nonunion will be managed. Options include a bone stimulator, nonunion repair with or without graft, revision fixation, or conversion to hip arthroplasty.

Laterality note: S72.145M is the left-side code

S72.145M already specifies the left femur, so it is a fully specific code. Laterality only becomes a problem when the record names a different side, or no side at all. ICD-10-CM guidelines require the most specific code the documentation supports.

Payers compare the side on follow-up claims with the side on the original fracture claim. A left-sided S72.145M after a right-sided S72.144B is likely to draw a review.

Payer requirements and Medicare coverage for nonunion fracture management

Medicare coverage for nonunion fracture management follows general medical necessity principles established by the CMS ICD-10 coding and billing guidance. Specific requirements vary by Medicare Administrative Contractor (MAC) jurisdiction. Always verify the applicable Local Coverage Determination before billing revision surgery.

Commonly required documentation elements across most MAC policies include:

• Serial imaging showing no progress toward union, such as a persistent fracture line without bridging callus
• A physician narrative explaining why nonunion occurred and what the current treatment plan addresses
• Prior treatment history showing that conservative management was attempted before surgery is authorized
• For surgical procedures, an operative report that ties the procedure to the nonunion diagnosis with enough specificity to meet medical necessity criteria

CPT code pairings for S72.145M

Procedure selection depends on the operative report. The pairings below reflect common scenarios for an intertrochanteric nonunion, and they do not replace documentation-driven code assignment.

CPT 27236 describes open treatment of a femoral neck fracture, so it does not pair with this intertrochanteric code. When the operative note describes a cephalomedullary nail, check the documentation rules for CPT 27245 before you pair it with S72.145M. A separately harvested graft goes to CPT 20902, and only when the primary code does not already include it.

Common claim denial reasons for S72.145M

Denials on S72.145M claims cluster around a predictable set of documentation and coding errors. Understanding the medical billing compliance requirements for nonunion fractures helps avoid the most common ones:

• Wrong anatomy. A femoral neck diagnosis (S72.0-) or a neck procedure such as CPT 27236 conflicts with an intertrochanteric imaging and operative record.
• K, M, and N mixed up. M requires an open type I or II fracture. If the original record shows a closed fracture or a type III wound, the claim is unsupported.
• Wrong 7th character for the visit. A and B are for initial encounters only. A follow-up visit for nonunion takes a subsequent-encounter character.
• No imaging confirming nonunion. Payers require objective evidence. A note saying “still has hip pain” does not establish nonunion without a radiology or surgical report.
• Side conflicts with claim history. A left-sided code after right-sided claims for the same fracture triggers automated edits on many MAC systems.
• Global period conflicts. Billing a separate visit inside the global surgery period of the original fixation creates a date conflict that triggers payer review.
• Missing original injury date. Some MAC LCDs require the date of injury on the claim form. Confirm field 14 on the CMS-1500 is populated.

Our guide to the clean claim process covers the pre-submission checks that catch most of these errors before a payer sees them.

Coding tips and best practices for intertrochanteric nonunion

These practical steps apply each time ICD-10 Code S72.145M is under consideration:

• Confirm the fracture site first. Intertrochanteric (S72.14-), base of neck (S72.04-), and subtrochanteric (S72.2-) fractures sit close together. Read the radiology report rather than relying on a note that just says hip fracture.
• Verify the encounter type. Decide whether this is active treatment of the original fracture or a follow-up visit. If it is unclear, review the claim history and prior notes before assigning M.
• Match K, M, or N to the original wound. Closed takes K, open type I or II takes M, and open type III takes N. Query the surgeon when the type is ambiguous.
• Check side and displacement together. Both live in the sixth character. A left, nondisplaced fracture is 5; a left, displaced fracture is 2.
• Distinguish nonunion from delayed healing. H is the open type I or II character for delayed healing that is still progressing. Reserve M for documented nonunion.
• Link the code to the original injury date. Field 14 on the CMS-1500 should carry the date of the fracture, not the date of the current visit.

How Pabau keeps S72.145M nonunion claims clean

Errors on S72.145M claims usually start upstream. A femoral neck code gets picked from a hip fracture shortlist, or the 7th character is keyed from memory. Catching that by hand means rereading every follow-up chart before the claim goes out.

Pabau checks each claim in its claims management software before submission. Claims then go out through our Claim.MD clearinghouse integration, which validates ICD-10-CM codes against payer rules for thousands of US payers.

Seventh-character and laterality conflicts get caught before transmission. That gives a nonunion visit its best chance of being paid on the first pass, rather than after an appeal.

Reduce coding denials before they reach the payer

Pabau’s claims management and Claim.MD clearinghouse integration check 7th characters, laterality, and code pairings before submission. See how it works for orthopedic and surgical billing.

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Conclusion

Coding S72.145M correctly starts with the anatomy. An intertrochanteric fracture sits below the femoral neck, so it belongs in S72.14-, not in the neck codes of S72.0-. Settle the site, then the side and displacement, and the sixth character follows.

The second judgment is the original wound. Closed fractures take K, open type I or II fractures take M, and type III wounds take N as the 7th character. Coding the wound the surgeon documented keeps these claims out of the denial queue.

Book a demo to see how Pabau checks fracture follow-up claims before they reach the payer.

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