ICD-10 Code S80.01XS: Contusion of right knee, sequela

Key takeaways

ICD-10 Code S80.01XS is the billable ICD-10-CM code for contusion of right knee, sequela, effective October 1, 2025.

The seventh character S marks a resolved injury whose late effect, such as stiffness or chronic pain, now needs treatment.

Never use S80.01XS for an active or healing knee contusion, which takes S80.01XA or S80.01XD instead.

Sequela claims are denied most often when the notes never confirm that the acute contusion has resolved.

Practice management software like Pabau scrubs the seventh character and the laterality before the claim reaches the payer.

ICD-10 Code S80.01XS is a billable, specific ICD-10-CM diagnosis code for contusion of right knee, sequela. It is valid for fiscal year 2026, effective October 1, 2025. The code covers any late effect of a right knee contusion that persists once the acute phase has resolved.

The code belongs to chapter S00-T88. The Centers for Medicare and Medicaid Services (CMS) lists that chapter as Injury, Poisoning, and Certain Other Consequences of External Causes. Within that chapter it sits in category S80, Superficial injury of knee and lower leg.

Right knee contusion claims are usually coded at the initial encounter and never revisited. Months later the patient comes back with chronic stiffness, lingering tenderness, or a functional limitation, and the coder reaches for the wrong seventh character. Medical billing workflows for sequela conditions call for a different code, and that code is S80.01XS.

Code details at a glance

Use the reference table below to confirm the key attributes of S80.01XS before submitting a claim.

Understanding the seventh character: A, D, and S

The seventh character is where most knee contusion coding errors originate. All three variants of S80.01X share the same base description, but they indicate different stages of care. Selecting the wrong character triggers denials and documentation audits.

The common error runs like this. A physical therapist keeps using S80.01XD for a patient whose contusion healed three months ago, because the knee still hurts. Once the bruising and the acute inflammatory response have resolved, the correct code is S80.01XS.

That distinction decides how payers classify the claim, and whether they approve it under injury-follow-up or late-effect coverage rules. Three questions, asked in order, settle which character applies.

What is a sequela in ICD-10 coding?

Sequela is the ICD-10-CM term for a late effect. It is a condition that arises as a direct consequence of a prior injury or illness, once the acute phase has ended. The CDC/NCHS ICD-10-CM coding tool classifies sequela under the “S” seventh character across all injury code families, including S80.

• The original injury is resolved. No active bruising, swelling, or acute inflammatory process is present.
• A residual condition now exists. The patient’s current complaint – stiffness, chronic pain, weakness, or fibrosis – traces directly back to the contusion event.
• Two codes may be used together. Per ICD-10-CM Official Guidelines Section I.B.10, you may code the sequela condition first. You can then add the original injury code with the “S” seventh character to show the cause.
• No time requirement. Sequela can manifest weeks, months, or years after the original injury. Time elapsed since the event does not determine the seventh character – injury resolution does.

When to use S80.01XS

Clinicians treating athletes, workers’ compensation patients, and post-injury rehabilitation patients encounter this code most frequently. The scenarios below are the primary clinical situations where S80.01XS applies.

• Chronic post-contusion knee pain. A patient sustained a right knee contusion six weeks ago and completed acute treatment. They now present with residual aching or tenderness that does not respond to standard care.
• Post-contusion stiffness or reduced range of motion. Restricted flexion or extension persisting after bruising and swelling have fully resolved – a common sequela in sports injuries managed by sports medicine practices.
• Scar tissue or soft-tissue fibrosis. Palpable thickening in the periarticular tissues of the right knee attributable to the original contusion, documented after acute healing is complete.
• Functional limitation as a late effect. Documented reduction in weight-bearing capacity, gait abnormality, or activity restriction that clinicians link directly to the original right knee contusion event.
• Physical therapy for residual deficits. PT or OT services initiated specifically to address functional limitations remaining after acute contusion care has concluded.

If the patient’s notes still describe active bruising or the contusion as “healing,” S80.01XS is premature. Use S80.01XD until the clinical record explicitly documents resolution of the acute injury.

ICD-10 Code S80.01XS in the code hierarchy

S80.01XS sits at the most specific level of a seven-tier structure. Reading the levels from the top shows what each character adds, and where a shorter code would have stopped.

The placeholder “X” in the sixth position is a required dummy character. Omitting it and coding “S80.01S” produces an invalid code that payers will reject. Always include the X placeholder when the sixth character position is not otherwise filled.

Related ICD-10 codes for knee contusion

The S80 code family covers superficial injuries to the knee and lower leg. Knowing the whole set matters for patients who present with bilateral or multi-site contusions, and for crosswalking a claim between encounter types.

Always specify laterality. Unspecified knee codes (S80.00X-) are valid, but they leave the record vaguer than the clinical picture warrants.

Payers and auditors increasingly flag unspecified laterality as a documentation deficiency, particularly in workers’ compensation and Medicare Advantage claims. Confirm right or left from the clinical record before coding.

Clinical documentation requirements for contusion of right knee, sequela

Sequela codes require stronger documentation than initial or subsequent encounter codes. The coder has to establish two distinct facts: the original injury occurred, and it has since resolved leaving a residual condition.

• Laterality confirmed as right. The clinical note, imaging report, or physical exam must explicitly name the right knee. Do not infer laterality from prior claims.
• Mechanism of original injury documented. A brief reference to the prior contusion event – fall, direct blow, sports impact – establishes the cause-and-effect chain required for sequela coding.
• Acute phase resolution stated. The current note should confirm that the bruising, swelling, and acute tenderness have resolved. “Acute right knee contusion resolved” or equivalent language is sufficient.
• Current sequela manifestation described. Document the specific residual condition being treated today: “persistent lateral knee stiffness,” “chronic aching post-contusion,” or “reduced range of motion following prior right knee contusion.”
• Temporal link established. The note should connect the current complaint to the original injury. A statement such as “patient continues to experience right knee stiffness as a result of contusion sustained [date]” satisfies this requirement.

Physical therapists in particular should verify that their intake documentation includes all five elements above before submitting S80.01XS on a claim.

Incomplete sequela documentation is the primary reason these claims are returned or denied on initial review. Consult the AAPC Codify ICD-10-CM lookup for additional coding notes specific to this code family.

Billing and reimbursement considerations

Sequela codes behave differently from initial and subsequent encounter codes at the payer level. Billing teams that treat S80.01XS like a routine follow-up code will meet denials they could have prevented.

Physical therapy and rehab billing

S80.01XS turns up often in physical therapy billing. It applies when a patient starts a course of rehab for residual deficits from a past right knee contusion. Make sure the plan of care names the sequela as the current diagnosis rather than the original injury.

Payers may request the referral or physician order to confirm the treatment rationale. Physical therapy practice software that supports structured ICD-10 coding at the point of care helps here. It lowers the risk of picking the wrong seventh character under time pressure.

Workers’ compensation considerations

Workers’ compensation payers often require pre-authorization for treatment of sequela conditions. The insurer may already have an open claim for the original contusion under S80.01XA or S80.01XD.

A new claim under S80.01XS can then need its own authorization request, with documentation showing the acute injury has resolved.

Check the payer’s claims portal before submitting. Practices that use electronic claims via Claim.MD can validate payer-specific requirements before submission, which cuts the turnaround time on sequela-coded workers’ compensation claims.

Common denial reasons for S80.01XS

Understanding managing claim denials for sequela codes starts with the three most common rejection triggers.

• Missing acute-phase resolution documentation. The claim arrives without clinical notes confirming the contusion has healed. Payers cannot validate the sequela relationship and return the claim for additional information.
• Wrong seventh character. S80.01XD submitted when S80.01XS is correct, or vice versa. Payers may pay the initial claim, then flag the account on audit when the character sequence does not match the documented care timeline.
• Unspecified laterality. S80.00XS (unspecified knee) claims attract more scrutiny than laterality-specific codes. Medicare Advantage payers increasingly require laterality to be documented before approving sequela-coded claims.

Practices managing a high volume of sequela claims benefit from a clearinghouse that checks claim data before transmission. Claims management software integrated with a clearinghouse catches seventh-character mismatches and missing laterality at the scrubbing stage, before the claim reaches the payer.

Check the code-level edits and pairing logic for the S80 family before you build a clean claim process for injury codes. Physical therapy practices should also revisit their documentation protocols each year, because payer audit standards for sequela codes keep tightening.

How Pabau handles sequela documentation and claim submission

In many practices this work is split across two systems. The clinical note sits in the EMR and the claim is built somewhere else. Someone retypes the diagnosis from one screen into the other, and that retyping is where a seventh character slips.

Practice management software like Pabau keeps the note and the claim in the same client record. The therapist documents that the acute contusion resolved and names the residual condition being treated. The coder then builds the claim from that note, with no second data entry step in between.

Claims leave through the Claim.MD clearinghouse integration, which checks the code before a payer ever sees it. So your team spends its time on treatment instead of re-submitting a claim that was right apart from one character.

Manage sequela claims and clinical documentation in one place

Pabau helps physical therapy, sports medicine, and rehab practices document sequela conditions accurately. Submit claims through the Claim.MD clearinghouse integration and track claim status without switching between systems.

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Conclusion

The seventh character is a clinical judgment before it is a clerical one. S80.01XS only holds up when the note says the acute contusion resolved and names what the patient is left with. Without those two statements the code is premature, whatever the calendar says.

So build the check into the documentation step rather than the billing step. A therapist who writes “acute contusion resolved, residual stiffness on the right” has already made the coder’s decision. At the point of submission, the claim stops being a judgment call.

Pabau’s claims management software connects to the Claim.MD clearinghouse and validates ICD-10 codes, including the seventh character, before claims reach payers. To see how a sequela claim runs end to end in a rehab practice, book a demo with the team.

Continue your research

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