ICD code S52.572M – Other intraarticular left radius fracture with nonunion

Key takeaways

S52.572M is the billable ICD-10-CM code for an open intraarticular fracture of the left distal radius that has not united. It applies at follow-up visits after an open type I or II injury.

Nonunion means the fracture has failed to heal. A fracture that healed in the wrong position is a malunion, which takes P, Q, or R instead.

The M character depends on the original open fracture grade. A closed fracture takes K, and an open type IIIA, IIIB, or IIIC fracture takes N.

S52.572 is the left side. Use S52.571M for the right radius and S52.579M only when the record never states a side.

Nonunion repair codes 25400 and 25405 are the usual surgical pairings, and 25405 already includes harvesting the autograft.

ICD-10 Code S52.572M: Definition and billable status

ICD-10 Code S52.572M is a valid, billable ICD-10-CM code for an open intraarticular fracture of the left distal radius with nonunion. It applies at a subsequent encounter, and the open fracture was graded type I or II. It has been valid since October 1, 2015, and it remains unchanged in the 2027 code set.

In plain terms, the patient broke the joint surface at the wrist end of the left radius, and the skin was broken at the injury. Treatment has moved past the acute phase, yet the bone ends have not knitted together.

Code details at a glance

What S52.572M covers: Breaking down the code

Each part of the descriptor narrows the code, and each one has to be supported by the record. Here is what the five components mean.

• Other intraarticular: The fracture line enters the radiocarpal joint, but it does not match a named pattern. Colles (S52.53-), Smith (S52.54-), and Barton (S52.56-) fractures each have their own subcategory. Use the named code whenever the record identifies one.
• Lower end of left radius: The distal metaphysis and epiphysis of the left radius, including the joint surface. Shaft fractures and radial styloid fractures (S52.51-) code elsewhere in S52.
• Subsequent encounter: The visit falls after the acute treatment phase. Any provider can report it, because the 7th character tracks the phase of care rather than who treated the patient first.
• Open fracture type I or II: The injury broke the skin, and the surgeon graded the wound Gustilo-Anderson type I or II at presentation. That grade carries forward to every later encounter.
• Nonunion: The fracture has failed to unite. Imaging shows a persistent fracture line and no bridging bone, and the treating provider has diagnosed nonunion.

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

Category S52 uses 16 seventh characters, and M is one of three nonunion values. The table shows the full set, so the M row can be read against its neighbors.

Nonunion vs. malunion: These are opposite outcomes. Nonunion (K, M, N) means the bone has not healed. Malunion (P, Q, R) means it healed, but in the wrong position. A coder who reads M as malunion will put the claim on the wrong clinical footing.

Nonunion vs. delayed healing: Delayed healing (H for an open type I or II fracture) means union is slow but still progressing. Move to M only when the provider documents that healing has stopped and diagnoses nonunion. Serial wrist radiographs, billed with CPT 73110, give the provider the evidence for that call.

The official guidelines settle when these characters apply. Section I.C.19.c.1 says care for malunion and nonunion is reported with the subsequent-care characters for nonunion (K, M, N) or malunion (P, Q, R). That holds even when the visit is a surgical repair.

Gustilo-Anderson grade and why it decides M over K or N

ICD-10-CM bases its open fracture characters on the Gustilo-Anderson classification. The surgeon grades the wound at the original injury, usually in the initial debridement note. That grade then decides the nonunion character months later.

The category notes add a default that catches many claims. A fracture not documented as open or closed is coded as closed. If the follow-up note never says the injury was open, the code falls to S52.572K unless the original record is checked.

Laterality and commonly confused codes

The S52.57 family splits by side, encounter type, open fracture grade, and healing status. These are the codes most often swapped with S52.572M.

Decision rule: Answer three questions in order. Which side does the record name? Was the original fracture open, and at what grade? Has the provider diagnosed nonunion rather than delayed healing or malunion? Left, open type I or II, and nonunion together give S52.572M.

Includes, excludes, and official coding notes

The tabular notes for S52 and S52.5 decide when another code takes priority. Check them before assigning S52.572M.

What the code includes

• Intraarticular fractures of the left distal radius that do not fit the Colles, Smith, or Barton patterns
• Fractures at the radiocarpal joint surface that were open at presentation and graded Gustilo type I or II
• Follow-up visits, including surgical repair, where the provider has diagnosed nonunion

What the code excludes

• Excludes1 at S52: Traumatic amputation of forearm (S58.-) cannot be coded with S52.572M.
• Excludes2 at S52: Fracture at wrist and hand level (S62.-) and periprosthetic fracture around an internal prosthetic elbow joint (M97.4). Either may be coded alongside S52.572M when both conditions exist.
• Physeal fractures: Growth plate fractures of the lower end of the radius code to S59.2- in skeletally immature patients.
• Stress and pathological fractures: These code to Chapter 13, such as M84.3- for stress fractures. S52 covers traumatic fractures only.
• Named patterns: A Colles, Smith, or Barton fracture with nonunion takes the M character in its own subcategory, not in S52.57.

Clinical documentation requirements for S52.572M

Coders assign S52.572M from provider documentation, not from their own reading of an imaging report. Five elements need to appear in the record before the code is safe to submit.

1. An explicit nonunion diagnosis. The provider writes “nonunion”, “ununited fracture”, or “failure of union”. A radiology line such as “persistent lucency at the fracture site” only counts once the provider adopts it as a diagnosis.
2. The original open fracture grade. The record shows the injury was open and graded type I or II. The current note can cite the initial operative or emergency record.
3. The left side. The note, imaging, or operative report names the left wrist. Without a side anywhere in the record, S52.579M applies instead.
4. Follow-up context. The note shows this visit follows the acute treatment phase. Time since injury and the prior treatment, such as plate fixation or casting, should both appear.
5. Infection status. Open fractures carry a higher risk of infected nonunion. When the provider documents infection, code it as well, such as osteomyelitis from category M86.

Orthopedic and physical therapy practices managing wrist fractures benefit from follow-up templates that prompt for all five elements at each visit.

CPT codes commonly paired with S52.572M

A nonunion follow-up usually leads to one of three paths: monitoring, bone healing stimulation, or surgical repair. These CPT codes cover each path. Descriptors follow the AMA CPT code set.

Two code families are often billed here by mistake. CPT 25608 and 25609 describe open treatment of an acute intraarticular distal radius fracture, not repair of a nonunion. The osteoplasty codes describe length correction instead.

One example is 25391, “Osteoplasty, radius OR ulna; lengthening with autograft”. Report it only when the operative note documents a separate lengthening procedure, and check NCCI edits first.

Verify each pairing against the current AMA CPT codebook and the patient’s record before submission. Practices that route claims through claims management software can apply CPT-to-ICD-10 crosswalk rules before a claim leaves the system. Submitting claims through a Claim.MD clearinghouse adds payer edits that flag mismatches before adjudication.

Payer requirements and prior authorization

Payer rules for S52.572M vary by insurer and Medicare jurisdiction. The points below are common expectations, not universal ones, so verify each payer’s current policy before submitting.

• Serial imaging. Payers expect radiographs over time showing that healing has stopped. One film rarely supports a nonunion diagnosis on its own.
• Bone stimulator criteria. Medicare’s osteogenic stimulator policy (NCD 150.2) treats a long-bone nonunion as established once serial radiographs show healing has ceased for at least 3 months. The two sets must be at least 90 days apart.
• Prior authorization for repair. Most commercial payers require authorization for 25400 and 25405. Send the imaging, the functional assessment, and the planned procedure before scheduling surgery.
• Open fracture history. Reviewers check that the claim’s open fracture grade matches the initial encounter record. Keep that record easy to retrieve.
• Medicare LCD review. Medicare Administrative Contractors publish jurisdiction-specific Local Coverage Determinations for fracture care. Running insurance eligibility verification before the visit confirms which MAC policy applies.

Common claim denial reasons for S52.572M

Most S52.572M denials trace back to a character, side, or bundling error. These six patterns come up most often, each with its fix.

• K instead of M. The follow-up note omits the open fracture history, so the coder defaults to closed. Fix: pull the initial encounter record and confirm the Gustilo grade.
• M read as malunion. The claim pairs S52.572M with a malunion procedure or a note describing a healed deformity. Fix: use S52.572Q when an open type I or II fracture healed out of position.
• Wrong side. S52.572M goes out for a right wrist, or S52.579M goes out when the side is documented. Fix: match the code to the side in the imaging and operative reports.
• Graft harvest billed twice. A separate bone graft code is billed with 25405. Fix: remember that 25405 includes obtaining the autograft.
• Acute fracture codes on a nonunion. 25608 or 25609 is billed with S52.572M. Fix: use the 25400 family for nonunion repair.
• Missing modifier 57. The E/M visit where the surgeon decides on nonunion repair falls on the day of or the day before surgery. Fix: append modifier 57 so the decision visit is paid outside the global package.

Practices with a structured denial management process catch these patterns before they reach the payer.

Reviewing the denial codes alongside the claim history shows whether the root cause was documentation or coding. Sending clean claims from the outset is faster than appealing after adjudication.

How Pabau keeps S52.572M nonunion claims clean

Nonunion claims depend on facts recorded months apart. The Gustilo grade sits in an emergency or operative note from the injury. The nonunion diagnosis appears in a follow-up note months later, often written by a different provider.

Pabau, the practice management platform we build for orthopedic, physical therapy, and multi-specialty practices, keeps those notes on one patient timeline. The open fracture grade stays visible at every later visit, so the coder can support M over K without a records request.

Pabau’s claims tools link diagnosis codes to procedure codes at the point of service and run edit checks before release. A 25405 claim with a separate graft code, or a malunion note under a nonunion code, is flagged before the payer sees it.

Keep fracture nonunion claims clean

Pabau links diagnosis and procedure codes at the point of service and flags 7th character and bundling errors before a claim leaves the practice. Book a demo to see it on your fracture claims.

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Conclusion

S52.572M rests on three facts recorded at different times. They are the left side, an open type I or II grade at the injury, and a nonunion diagnosis at follow-up. Lose any one of them and the claim drifts to K, N, Q, or the wrong side.

The practices that bill this code cleanly treat the original Gustilo grade as part of the diagnosis rather than a detail of the first visit. They also keep nonunion and malunion apart in every note and claim. To see how Pabau’s medical billing workflows support that across a long fracture episode, book a demo.

Continue your research

Want to understand the full medical billing lifecycle behind this code? Revenue cycle management explains how ICD-10 code accuracy fits into collections, appeals, and clean-claim rates.

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