ICD-10 Code S99.101D: Unspecified physeal fracture of right metatarsal

Key takeaways

ICD-10 code S99.101D reports an unspecified physeal fracture of the right metatarsal, subsequent encounter for fracture with routine healing.

The S99.1 subcategory covers metatarsal growth plate fractures only. Physeal fractures of a toe phalanx belong to the separate S99.2 subcategory.

S99.101 takes seven valid 7th characters: A, B, D, G, K, P and S. The D character applies only when healing is routine.

When the physician documents a Salter-Harris type, move to S99.111D, S99.121D, S99.131D, S99.141D or S99.191D.

Practice management software like Pabau keeps laterality, encounter phase and healing status in the record at every follow-up visit.

ICD-10 code S99.101D reports an unspecified physeal fracture of the right metatarsal, seen at a follow-up visit where the fracture is healing routinely. It is billable in the FY2026 edition. The growth plate is involved, the side is right, and the Salter-Harris type is absent from the note.

S99.1 is the metatarsal subcategory, while physeal fractures of a toe phalanx sit in S99.2. Mixing up those two families is the most common site error on this code. This reference covers the official descriptor and the full set of valid 7th characters under the CMS ICD-10-CM Official Guidelines. It also covers the laterality variants, the documentation requirements and the common CPT pairings.

ICD-10 code S99.101D: code at a glance

S99.101D is a billable, valid-for-submission ICD-10-CM code in the FY2026 edition, effective October 1, 2025. The table below summarizes every field a coder or billing team needs before submitting a claim.

What is a physeal fracture of the metatarsal?

The physis, commonly called the growth plate, is a cartilaginous zone near the end of a long bone where longitudinal growth happens. In children and adolescents it is structurally weaker than the surrounding bone. That makes it the most common fracture site in skeletally immature patients. Metatarsal physeal fractures usually follow a twisting injury, a fall, a dropped object or repetitive loading in a young athlete.

Because the physis is still growing, these injuries carry more weight than the equivalent fracture in an adult. Damage to the growth plate can disturb normal growth and cause angular deformity or a length discrepancy in the ray. That clinical significance is why ICD-10-CM gives metatarsal physeal fractures their own subcategory, S99.1. They are not grouped with the general metatarsal fracture codes in S92.3.

Salter-Harris classification and ICD-10 coding

The Salter-Harris system classifies physeal fractures by how the fracture line crosses the growth plate, the epiphysis and the metaphysis. ICD-10-CM gives each type its own code. The unspecified code applies only when the physician has not documented the type. Coders should never assign a Salter-Harris type without explicit physician documentation.

The 7th character: what D means and which others are valid

The 7th character on an ICD-10-CM fracture code signals the phase of care and the healing status, not the severity of the injury. S99.101 accepts seven of them, so D is one option out of seven rather than one out of three. Four of those characters describe a subsequent encounter, and they are separated by how the fracture is healing. Tibial shaft codes such as S82.222E carry a longer set that also names the open fracture type.

D does not cover every visit after the first. It requires aftercare during the healing phase and a record that describes routine healing. If the note documents delayed healing, nonunion or malunion, the characters G, K and P apply instead. Confirm the healing status in the note before you apply D.

Code hierarchy: where S99.101D sits in ICD-10-CM

Reading the code tree top down helps coders catch hierarchy errors before submission. Each level narrows the clinical picture by one step. For a full hierarchy view, AAPC Codify lets you browse the S99 block interactively.

• S00-T88 – Injury, poisoning and certain other consequences of external causes (chapter)
• S90-S99 – Injuries to the ankle and foot (block)
• S99 – Other and unspecified injuries of ankle and foot (category)
• S99.1 – Physeal fracture of metatarsal (subcategory)
• S99.10 – Unspecified physeal fracture of metatarsal
• S99.101 – Unspecified physeal fracture of right metatarsal (requires a 7th character)
• S99.101D – Unspecified physeal fracture of right metatarsal, subsequent encounter for fracture with routine healing

S99.101 is not itself billable. It is a six-character base code that needs the 7th character to become valid for submission. Coders working in physical therapy EMR environments or orthopedic practices should confirm the documented bone before choosing from the S99.1 subcategory.

Related ICD-10 codes for metatarsal physeal fractures

Laterality, fracture type and encounter character together decide which code applies. The table below shows the variants most often needed alongside S99.101D. Getting these relationships right prevents laterality substitution, one of the most common denial triggers in orthopedic billing.

Laterality: right, left and unspecified metatarsal

ICD-10-CM requires laterality on every metatarsal physeal fracture code. Unspecified laterality codes exist, but treat them as audit flags. Payers scrutinize claims that report unspecified laterality when the record clearly names the injured side. Use the unspecified code only when the physician documentation genuinely omits the side.

• Right metatarsal (S99.101D) – use when the documentation states right, with no ambiguity.
• Left metatarsal (S99.102D) – the mirror code for left-sided injuries. The digit in the fifth position carries laterality, so 1 is right and 2 is left.
• Unspecified metatarsal (S99.109D) – use only when laterality is missing from the record, and query the physician first where possible.

The same pattern runs through the whole subcategory. S99.111D and S99.112D are the Type I right and left codes, and S99.121D and S99.122D are the Type II pair. Reliable patient record management that captures laterality at every visit reduces reliance on unspecified codes and lowers denial risk.

Metatarsal, toe or tarsal: choosing the right code family

The S99 physeal fracture subcategories are organized by bone, and the neighboring families look almost identical at a glance. Check the documented bone in the note against this list before you select a code.

Two rules follow from that table. A note that says toe fracture does not support S99.101D, because the toe phalanx family is S99.2. A note that says metatarsal fracture without naming the growth plate does not support it either, because a non-physeal metatarsal fracture belongs in S92.3. The same logic runs through the hindfoot, where a talar dome fracture such as S92.145K sits in S92.1.

Documentation requirements for ICD-10 code S99.101D

Four elements must appear in the clinical record to support S99.101D on a claim. Incomplete documentation is a frequent cause of denials on physeal fracture claims. Build these prompts into your medical diagnosis form so they are captured at the point of care.

1. Laterality confirmed as right – the treating physician states right in the note. Entries that say only foot, or same as last visit, are not enough.
2. Site named as the metatarsal growth plate – the note must identify a physeal or growth plate fracture of a metatarsal. A general toe fracture note points to S99.2 instead.
3. Encounter phase is aftercare – the visit reflects care after the active treatment phase, such as healing review, cast change or follow-up imaging.
4. Healing status is routine – if the record notes delayed healing, nonunion or malunion, the correct character is G, K or P rather than D.

One more note for coders. When the physician documents the Salter-Harris type at a subsequent encounter, switch to the matching specific code. The same specificity rule governs physeal fracture codes elsewhere in the body, such as S59.199S at the radius.

Billing and reimbursement guidance for S99.101D

S99.101D is accepted by Medicare, Medicaid and most commercial payers for FY2026. Reimbursement is not automatic, though. Payer policies differ on documentation, and some carriers apply medical necessity review once follow-up visits pass a set frequency. Claims management software that keeps the diagnosis codes with the claim record makes that check quick before submission.

Denials on S99.101D cluster around four causes. The first is a D character on a note that describes active initial treatment. The second is a D character where the note describes delayed healing, nonunion or malunion. The third is a right-sided code on a left-sided injury. The fourth is staying on the unspecified code when the physician documented a Salter-Harris type.

Common CPT codes used with S99.101D

The CPT codes below are the ones most often reported at metatarsal fracture follow-up visits. These pairings are examples only, and the correct code depends on the service rendered. Check your payer’s local coverage determination for medical necessity criteria before you bill them.

One caveat on the casting codes. The first cast applied as part of the initial fracture care package is bundled into that service. A replacement cast applied at a later visit is generally reportable on its own. Practices that connect notes and billing through EHR integration can see the healing status recorded that day before the casting code goes out.

Pediatric considerations for metatarsal physeal fracture coding

S99.101D applies to any patient with an open physis. In practice that means children and adolescents most of the time, though a young adult with delayed physeal closure can also qualify. Pediatric metatarsal physeal fractures carry a few coding implications beyond routine fracture management.

• Growth disruption risk – even routinely healing physeal fractures warrant longer follow-up in growing patients, so expect more D-character encounters per episode.
• Salter-Harris specificity matters more – pediatric surgeons usually document the type because it predicts growth disturbance. Query for it before defaulting to S99.101D.
• Each visit stands alone – every follow-up note must independently support routine healing. Carrying forward last month’s wording will not survive an audit.
• Guardian documentation – consent and school clearance notes belong in the chart, but they do not affect code selection.

Physeal injuries elsewhere in the growing skeleton follow the same 7th character logic, as S59.229A does at the distal radius. A mixed adult and pediatric caseload therefore needs two sets of encounter templates. Sports medicine software that keeps them separate reduces missed documentation on growth plate injuries.

Coding tips and common errors to avoid

These are the errors that show up most often in orthopedic billing audits involving S99.101D and the wider S99.1 subcategory.

• Treating S99.1 as a toe code: S99.1 is the metatarsal subcategory. A documented toe phalanx growth plate fracture belongs in S99.2, so a right toe would be S99.201D.
• Reading S99.201D as the left-sided pair: it is not. The left metatarsal equivalent of S99.101D is S99.102D, and S99.201D is a right toe code.
• Assuming only A, D and S exist: S99.101 also takes B for an open fracture at the initial encounter. It takes G, K and P as well, for delayed healing, nonunion and malunion.
• Using D during active treatment: if the visit involves reduction, surgery or the first specialist evaluation, the character is A or B rather than D.
• Staying on unspecified when specificity exists: once the physician documents a Salter-Harris type, move to the matching code. Remaining on S99.101D invites audit queries.
• Confusing sequela with subsequent: S applies to late effects after healing is complete, such as growth arrest. Routine healing follow-up takes D.
• Missing the index path: look under Fracture, traumatic, physeal, then navigate by site. Searching the general fracture entries leads coders to S92 codes by mistake.

High-volume orthopedic practices benefit from a standing coding review that catches site and character errors before submission. EHR platforms that hold the note and the claim together make that review faster to run.

How Pabau supports accurate ICD-10 coding for orthopedic practices

Most coding errors on this code start in the clinical note, not in the coding step. A follow-up entry that omits the side, names the foot instead of the metatarsal, or skips the healing status leaves the coder guessing. The claim then goes out with an unspecified code or the wrong 7th character.

Practice management software like Pabau closes that loop by keeping the note, the diagnosis codes and the claim in one record. Custom clinical forms can require laterality, bone and healing status before the note is signed. Recurring follow-up appointments carry the same structure forward, so every visit in the episode is documented the same way.

Billing teams work from that record rather than chasing it. Pabau stores the diagnosis and procedure codes your coder selects, then submits and tracks the claim from the same screen. That means fewer denials to rework and a shorter path from the follow-up visit to payment.

Keep fracture follow-up coding accurate

Pabau helps orthopedic, podiatry and sports medicine practices capture laterality, site and healing status in the note. Claims are then submitted and tracked from that same record. See how it reduces denials on fracture follow-up visits.

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Conclusion

S99.101D reports one clinical situation and nothing wider. It applies to an unspecified physeal fracture of the right metatarsal at a follow-up visit where healing is routine. Change the bone, the side or the healing status and the code changes with it. The toe phalanx equivalent is S99.201D, the left metatarsal equivalent is S99.102D, and delayed healing moves you to S99.101G.

Accuracy on this code therefore depends on what the note captures at every encounter, not on the coder alone. Practices that prompt for laterality, bone and healing status in the record itself submit cleaner claims and rework fewer denials. Book a demo to see how Pabau handles orthopedic documentation and claims end to end.

Continue your research

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