ICD-10 Code S82.242N: Displaced spiral tibial shaft fracture

Key Takeaways

S82.242N describes a displaced spiral fracture of the shaft of the left tibia at a subsequent encounter for an open fracture type IIIA, IIIB, or IIIC with nonunion

The 7th character N specifically designates open fracture Gustilo types IIIA, IIIB, or IIIC with nonunion – distinct from K (closed nonunion) and M (open type I or II nonunion)

Nonunion requires clinical and radiographic confirmation; the coder assigns this 7th character only when the treating provider documents failure of the fracture to heal

Pabau’s claims management software helps orthopedic and physical therapy practices track fracture care episodes, attach accurate 7th character codes, and reduce claim denials

ICD-10 Code S82.242N: Definition and clinical description

Open tibial shaft fractures that fail to heal present one of the most complex coding scenarios in musculoskeletal billing. Most practices get the initial encounter right – it’s the subsequent encounter codes, particularly those involving nonunion and Gustilo type III open fractures, where documentation gaps and 7th character errors drive denials. ICD-10 Code S82.242N is a billable ICD-10-CM code describing a displaced spiral fracture of the shaft of the left tibia, at a subsequent encounter, for an open fracture type IIIA, IIIB, or IIIC with nonunion.

This code became valid for reimbursement claims with dates of service on or after October 1, 2015. It sits within ICD-10-CM chapter S00-T88 (Injury, poisoning and certain other consequences of external causes), under section S80-S89 (Injuries to the knee and lower leg). The parent category is S82 (Fracture of lower leg, including ankle), with S82.242 identifying the displaced spiral fracture of the shaft of the left tibia specifically.

Coders and clinicians at orthopedic, physical therapy, and sports medicine practices must understand the full context of this code before applying it. The 7th character is not a coder’s judgment call – it reflects clinical and radiographic findings that the treating provider must document.

7th character extensions for S82.242

The parent code S82.242 requires a 7th character to be complete and billable. Each 7th character captures two simultaneous clinical facts: the encounter type (initial, subsequent, or sequela) and the healing status or fracture category. CMS ICD-10-CM guidelines require that the 7th character accurately reflect the current stage of care.

The 7th character N is used exclusively when both conditions apply: the fracture was an open fracture classified as Gustilo type IIIA, IIIB, or IIIC, and the fracture has not united. Both facts must be present in the clinical documentation before the coder applies this character. Using structured clinical records that capture fracture type at the initial encounter makes subsequent coding far more accurate.

Gustilo-Anderson classification: what types IIIA, IIIB, and IIIC mean

The Gustilo-Anderson classification system, developed by the American College of Surgeons’ Committee on Trauma, grades open fractures by the extent of soft tissue injury and vascular involvement. The distinction between types matters for coding because ICD-10-CM uses it to differentiate 7th characters B/M/Q (type I or II) from C/N/R (type IIIA, IIIB, or IIIC).

• Type IIIA: High-energy wound with adequate soft tissue coverage despite extensive laceration or skin flap. Bone coverage is achievable without complex reconstruction.
• Type IIIB: Extensive soft tissue loss with periosteal stripping. Requires local or free-flap coverage. Often associated with massive contamination.
• Type IIIC: Any open fracture associated with an arterial injury requiring repair, regardless of soft tissue involvement.

The Gustilo type is a clinical determination made by the treating surgeon at or shortly after injury. Coders do not assign the type – they read it from the operative note, discharge summary, or follow-up documentation. If the original fracture type is not recorded, the coder cannot apply a type IIIA/IIIB/IIIC 7th character. Query the provider rather than assume.

Nonunion vs. delayed healing vs. malunion: clinical distinctions

These three outcomes represent different trajectories of fracture healing. Each maps to a different 7th character group, and mixing them up generates denials.

• Routine healing (D, E, F): Fracture is progressing toward union on expected timeline. No complications documented.
• Delayed healing (G, H, J): Healing is occurring but more slowly than expected. Radiographic evidence of callus formation exists, but union is not yet achieved within the anticipated timeframe.
• Nonunion (K, M, N): Fracture has ceased healing. The biologic repair process has stopped. Confirmed by clinical assessment and radiographic evidence (typically at 6 months post-injury or when the provider determines healing is no longer progressing).
• Malunion (P, Q, R): Fracture has healed, but in a position that deviates from acceptable anatomical alignment.

For ICD-10 Code S82.242N to apply, the provider’s documentation must state or clearly imply nonunion – not just slow healing. Phrases like “fracture not healed,” “persistent nonunion,” “failed to unite,” or a surgical plan for nonunion repair support this coding. Delayed healing alone supports G, H, or J, not K, M, or N. Well-structured digital clinical documentation forms that include a fracture healing status field reduce query burden significantly at subsequent visits.

Documentation requirements for subsequent encounter coding

A subsequent encounter (7th character D through S) applies to every visit after the active treatment phase. Active treatment typically includes the initial surgical or non-surgical management and the immediate post-operative period. Once the patient enters routine follow-up, each visit uses a subsequent encounter character.

To support ICD-10 Code S82.242N specifically, the medical record must document all of the following at the time of the subsequent encounter:

• Confirmation that the original injury was an open fracture of the left tibial shaft with a spiral pattern
• Original Gustilo classification as type IIIA, IIIB, or IIIC (from initial encounter records)
• Current healing status assessed as nonunion (clinical and/or radiographic confirmation)
• Laterality confirmation: left tibia
• Encounter type: subsequent (not initial or sequela)

The CDC/NCHS ICD-10-CM coding tool provides the official tabular list and index for verifying these requirements. Per HIPAA, ICD-10-CM is the mandatory code set for covered entities reporting diagnosis codes on claims. Practices using claims management software that flags incomplete 7th character documentation before submission can catch these gaps before they become denied claims.

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Related codes adjacent to ICD-10 Code S82.242N

Choosing between adjacent codes is where many coders encounter uncertainty. The differences are laterality, fracture type, and healing status. The table below shows the most commonly confused codes alongside S82.242N.

Laterality errors (left vs. right) are among the most common reasons fracture claims are returned. Confirm laterality against the original operative report, imaging report, or emergency department documentation at every subsequent visit. The AAPC Codify ICD-10-CM lookup and the ICD List are useful secondary references for verifying adjacent codes in the S82.242 family. For the authoritative tabular list, use the CMS ICD-10-CM code files.

Commonly paired procedure codes for tibial shaft nonunion treatment

When S82.242N appears on a claim, the accompanying CPT code reflects the surgical or non-surgical intervention being performed at that encounter. Payer medical necessity policies vary, so verify coverage requirements before the procedure. Common pairings include:

• CPT 27722 (Repair of nonunion or malunion, tibia): The most common surgical code for tibial shaft nonunion repair. Requires documentation of nonunion diagnosis, operative approach, and grafting if performed.
• CPT 27724 (Repair of nonunion or malunion, tibia, with bone graft): Used when autograft or allograft is incorporated into the nonunion repair procedure.
• CPT 20900 or 20902 (Bone graft, any donor area): May be reported separately when autologous bone graft is harvested from a separate site, subject to payer rules.
• CPT 97014 / 97032 (Electrical stimulation): Some payers cover bone growth stimulator application for documented nonunion. Prior authorization is frequently required.
• E0747 / E0748 (HCPCS for bone growth stimulators): Durable medical equipment codes for external or implantable bone growth stimulators used as nonunion adjuncts.

Practices managing fracture nonunion patients across a physical therapy and orthopedic continuum benefit from clinic management workflows that flag the active diagnosis code episode across multiple visit types. Coordinating the care record across providers also reduces the risk of 7th character drift, where a coder at a follow-up visit applies the wrong healing-status character because prior encounter records were not reviewed. The compliance requirements for physiotherapy clinics managing post-fracture rehabilitation include maintaining continuous episode-of-care documentation.

Billing and reimbursement notes

S82.242N is a fully billable, specific ICD-10-CM code. It carries no “Not Elsewhere Classifiable” (NEC) or “Not Otherwise Specified” (NOS) qualifier. Payers expect this level of specificity for fracture nonunion claims, and submitting a less-specific parent code (such as S82.2 or S82.24 without a 7th character) will result in a rejection.

Key billing considerations for this code:

• Medicare coverage: Nonunion treatment is covered under Medicare when medical necessity is documented, including imaging evidence and the provider’s assessment of failed healing. Bone growth stimulator coverage requires prior authorization from most Medicare Administrative Contractors.
• Commercial payer variation: Coverage policies for nonunion repair vary significantly. Some payers require a minimum time post-injury (often 6 months) before approving nonunion repair CPT codes paired with this diagnosis.
• Modifier requirements: When bilateral procedures are performed (rare for tibial shaft fractures, but possible in polytrauma cases), modifier 50 or LT/RT modifiers may apply. Laterality is already specified in S82.242N (left), so LT modifier on the procedure code aligns correctly.
• Sequencing: S82.242N is sequenced as the principal diagnosis when the primary reason for the encounter is treatment of the tibial shaft nonunion. When the encounter addresses multiple injuries, sequence per ICD-10-CM Official Guidelines for injury sequencing.

Practices handling orthopedic and rehabilitation billing can reduce nonunion claim denials by using practice management platforms that link diagnosis codes to encounter documentation and alert coders to missing 7th character fields before claim submission. The ICD-10 code reference library on Pabau’s blog covers additional diagnostic codes across clinical specialties. For coding questions specific to fracture claim audits, the CDC/NCHS ICD-10-CM web tool provides the authoritative tabular list and alphabetic index.

How Pabau supports fracture nonunion billing workflows

Fracture care episodes span months – sometimes years – and involve multiple providers, multiple encounter types, and an evolving healing status. That complexity is exactly where documentation errors accumulate and denials compound.

Pabau’s claims management software supports orthopedic and musculoskeletal practices by centralising encounter records, linking the original injury documentation to every subsequent visit, and flagging diagnostic code fields that are incomplete at the time of claim generation. For practices managing post-fracture rehabilitation, compliance management tools within Pabau help ensure documentation standards are maintained across the full episode of care. Explore how Pabau handles complex multi-encounter billing workflows by booking a demo.

Conclusion

Tibial shaft nonunion after a high-energy open fracture is a high-stakes clinical and billing scenario. Applying the wrong healing-status or fracture-type character – K instead of N, or M instead of N – generates denials that slow reimbursement and frustrate audits. ICD-10 Code S82.242N is reserved for a specific combination: left tibial shaft, displaced spiral pattern, open fracture Gustilo type III, subsequent encounter, nonunion confirmed.

Accurate documentation of Gustilo type at the initial encounter, clear provider language confirming nonunion status, and a practice management system that links original injury records to subsequent visits are the three pillars of getting this code right. Pabau’s clinical record and episode management tools help practices maintain that continuity across the full fracture care episode. See how Pabau supports orthopedic and rehabilitation billing by booking a demo.

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