ICD code S82.013B – Displaced osteochondral fracture of unspecified patella

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Key takeaways

ICD-10 code S82.013B is a displaced osteochondral fracture of the unspecified patella, initial encounter for open fracture type I or II.

The patella is the kneecap. Subcategory S82.0 covers patella fractures and S82.01 narrows that to osteochondral fractures, despite the S82 category being named for the lower leg.

The digit 3 in S82.013 means the record did not document a side. Right is S82.011B and left is S82.012B, so query the chart before you settle for the unspecified code.

The 7th character B marks an initial encounter for a Gustilo type I or II open fracture. Character A is the closed equivalent and C covers type III.

Pabau’s claims management software integrates with Claim.MD to validate S82.013B and submit clean orthopedic claims to thousands of US payers.

Clinical description: Displaced osteochondral fracture of the patella

Each element of this descriptor is a separate coding decision. Misreading any one of them lands the claim on a different code.

• Displaced: The fragment of bone and cartilage has shifted out of its normal position. The nondisplaced equivalent is S82.016B. ICD-10-CM defaults to displaced when the record does not state either way.
• Osteochondral: The fracture line runs through the articular cartilage and the layer of bone directly beneath it. That separates it from the longitudinal, transverse and comminuted patella patterns coded in S82.02 through S82.04.
• Unspecified patella: The patella is the kneecap. Unspecified means the record never named the injured side. The right patella takes S82.011B and the left takes S82.012B.
• Initial encounter: The patient is receiving active treatment for the injury. Follow-up visits move to the characters D through R, and late effects use S.
• Open fracture type I or II: A wound connects the fracture to the outside. Types I and II come from the Gustilo-Anderson grading system, and the 7th character B carries both of them.

Laid out position by position, the seven characters show which decision each one records.

The patella sits directly under the skin with almost no soft tissue cover. A direct blow to a bent knee can break the bone and open the skin in the same movement. Dashboard injuries, falls onto hard ground, and motorcycle crashes are the mechanisms behind most open patellar fractures.

Why the unspecified side in S82.013B deserves a query

S82.013B should be rare on a finished claim. Laterality is the one axis a knee examination almost always settles, so an unspecified-side code usually signals a documentation problem rather than genuine clinical uncertainty.

The ICD-10-CM Official Guidelines allow unspecified codes where they most accurately reflect what the record shows at that encounter. A knee that has been examined, imaged, and often taken to the operating room does have a documented side somewhere. Four checks usually find it.

• Read past the discharge summary. The emergency triage note, the radiology report, and the operative report each record the side independently. One of the three normally resolves it.
• Check the imaging header. Radiographs and MRI studies are ordered by side, so the study title itself often supplies the laterality that the narrative left out.
• Expect payer edits. Many payers flag unspecified-laterality trauma codes for manual review. That delays payment even when the rest of the claim is clean.
• Then use S82.013B if you must. Where no source establishes a side, the code is valid and billable. It is a better answer than guessing right or left.

Open fracture types I and II under the Gustilo classification

The Gustilo-Anderson system grades open fractures by wound size, soft tissue damage, and contamination. ICD-10-CM folds types I and II together under the 7th character B. Types IIIA, IIIB and IIIC all map to character C instead. Conflating the two groups carries a direct billing consequence.

The tabular note under category S82 states that the open fracture designations are based on the Gustilo classification. The same note directs that a fracture not documented as open or closed is coded as closed. Grading is most reliable once the wound has been formally debrided, so the operative report usually carries the final type.

The 7th character: What B means for encounter type

The 7th character is the most frequently misapplied element in fracture coding. Every code in the S82.01 subcategory takes one of sixteen characters, which combine encounter phase with fracture type. Choosing A instead of B for an open type I or II fracture is a common and avoidable error.

The ICD-10-CM Official Guidelines, published jointly by CMS and NCHS, tie the 7th character to the phase of treatment at the current encounter. A patient returning for a wound check after a type I open patella fracture takes character E, not B.

ICD-10-CM code hierarchy for S82.013B

Only the full seven-character code is billable. Submitting S82.013, S82.01, or S82.0 on their own will be rejected for lack of specificity, because each of them has more detailed codes underneath.

The S82.0 entry carries the applicable-to term knee cap in the tabular list. That single annotation is the fastest way to confirm that this branch of S82 covers the kneecap and not the tibia. Proximal tibia fractures sit in S82.1 instead.

Approximate synonyms and equivalent terms

Provider documentation rarely uses the tabular wording. Any of these phrases in an operative report or emergency note should prompt a review against S82.013B, subject to a full record check.

• Displaced osteochondral fracture of the kneecap, open type I or II, initial treatment
• Displaced chondral and subchondral fracture of the patella with an open wound
• Open patellar osteochondral fracture, Gustilo type I or II, side not stated
• Displaced osteochondral fragment of the patella after an open knee injury
• Traumatic osteochondral defect of the patella, displaced, open fracture, first encounter
• Patellar articular surface fracture with a displaced bone and cartilage fragment, open

Notes describing a loose body, an osteochondral fragment, or a flake fracture of the patella also point to the S82.01 subcategory. Confirm displacement, laterality, and open fracture status before settling on a code.

Related ICD-10-CM codes for patellar fractures

Knowing the adjacent codes prevents laterality errors, displacement errors, and open or closed mismatches. These are the codes most often confused with S82.013B.

The AAPC ICD-10-CM code lookup carries the full descriptor set for each of these, along with the annotations attached to their parent codes.

Coding guidelines and documentation requirements

Four documentation elements have to be present before S82.013B holds up in an audit. The ICD-10-CM Official Guidelines for Coding and Reporting govern each of them.

1. Fracture pattern: The record must describe an osteochondral injury, meaning cartilage together with the bone beneath it. A transverse, longitudinal, or comminuted patella fracture codes elsewhere in S82.0.
2. Displacement status: A radiology or operative note stating displaced supports this axis. The tabular note under S82 directs that a fracture not described either way is coded as displaced.
3. Laterality: Documentation of the right or left knee moves the code to S82.011B or S82.012B. S82.013B applies only where no source in the record establishes a side.
4. Open fracture classification: The wound has to be documented as open and graded Gustilo type I or II. A clean wound under 1 cm supports type I, and a wound of 1 to 10 cm with moderate soft tissue damage supports type II.

Practices using claims management software with built-in ICD-10-CM catalogs can validate S82.013B while the claim is being built. Validation flags missing characters and invalid combinations before the claim ever leaves the practice.

Practice management software like Pabau integrates with the Claim.MD clearinghouse to route these claims to thousands of US payers. The clearinghouse then applies diagnosis-to-procedure crosswalk edits, which catch laterality and encounter-type mismatches.

The clean claim submission framework recommends checking all seven characters of a fracture code before the claim is generated. Catching it afterward costs a resubmission cycle.

Patellar osteochondral fractures in clinical context

An osteochondral fracture of the patella takes off a fragment of articular cartilage with the bone directly under it. Because the injury sits on the joint surface, it changes both the treatment plan and the follow-up imaging schedule.

Three features separate these fractures from the other patella patterns.

• Mechanism: Most follow an acute lateral dislocation of the kneecap. As the patella relocates, its medial facet shears against the lateral femoral condyle and a fragment breaks away. A direct blow to the front of a bent knee is the other common route, and it is the one that produces open injuries.
• Patient population: These injuries cluster in adolescents and young adults, particularly athletes in contact and pivoting sports. Skeletal maturity is not part of the code, unlike the physeal fracture series.
• Imaging: Cartilage is radiolucent, so a mainly chondral fragment can be invisible on plain radiographs. MRI or CT usually confirms the diagnosis, which means the fracture pattern may only appear in a report filed days after the visit.

An open patellar fracture is treated as a surgical emergency. Irrigation, debridement, antibiotics, and fixation or removal of the fragment usually happen on the day of presentation. That operative report is where the Gustilo grade, the displacement, and the injured side all appear together. It is the single most useful document for coding S82.013B correctly. The AAOS OrthoInfo overview of patellar fractures sets out the surgical options in more detail.

Sports injuries are a common mechanism, so practices treating adolescent athletes meet these codes often. Orthopedic documentation templates that prompt for wound status, laterality, and displacement at the point of care remove the query later.

Sequencing and additional code requirements

S82.013B is normally the principal diagnosis when the fracture is the reason for the visit. Several additional codes and sequencing rules apply alongside it.

• External cause codes: The note at the head of chapter S00-T88 applies here. It directs coders to add a secondary code from chapter 20 for the cause of injury. Fall, sports collision, and motor vehicle codes all apply to this fracture.
• Retained foreign body: The same chapter note instructs coders to add a code from Z18 for any retained foreign body. Open patella wounds caused by road surfaces or glass make this a live question.
• Activity and place of occurrence: Y93 activity codes and Y92 place of occurrence codes can be added as additional codes. Many payers expect them on trauma claims.
• Sequencing with surgical CPT codes: When the patient goes to surgery, S82.013B is matched to the procedure code through a medical necessity crosswalk. The CMS ICD-10 coding page hosts the current update files.
• Wounds managed separately: Where the open wound is treated as a distinct problem, sequencing can change. Check the Official Guidelines section covering traumatic fractures and open wounds.

On inpatient claims, S82.013B groups to MS-DRG 562 or 563 under version 43.1 of the grouper. Those cover fracture, sprain, strain and dislocation outside the femur, hip, pelvis and thigh. Cases with multiple significant trauma group to 963 through 965 instead.

NCHS and CMS update the ICD-10-CM code set every October 1. S82.013B has carried the same descriptor since 2015. Coders should still confirm its status against the current fiscal year files before processing a claim. Practices with high orthopedic volumes also benefit from tracking denials by reason code.

How Pabau helps practices code patella fractures accurately

A laterality or 7th character error usually surfaces weeks after the encounter. A payer rejects the claim and a biller pulls the chart. The clinician who treated the patient then gets asked what the record should already have said. By then the visit is months behind everyone involved.

Pabau moves that check to the point of claim build. The ICD-10-CM and CPT catalogs sit inside the billing screen, so an incomplete or invalid code cannot be saved onto a claim. The Claim.MD integration then runs clearinghouse edits before submission, including the diagnosis-to-procedure crosswalk checks that catch encounter-type mismatches.

The practical outcome is that the coder sees the problem while the chart is still open in front of them. Denials on orthopedic trauma claims fall, and the rework cycle gets shorter for every fracture code the practice bills.

Reduce claim denials on orthopedic fracture codes

Pabau integrates with Claim.MD to validate ICD-10-CM codes including S82.013B before submission. Built-in CPT and ICD-10 catalogs flag invalid character combinations, missing laterality, and encounter type errors across thousands of US payers.

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Conclusion

S82.013B is a displaced osteochondral fracture of the patella with a Gustilo type I or II open wound. It is coded at the initial encounter, with no side documented. The category name sends coders toward the tibia. The subcategory is the kneecap, and getting that right is the whole job.

Get the four axes right, and query the chart for laterality before you accept the unspecified code. Pabau validates S82.013B and its siblings against payer edits before submission, through its Claim.MD integration. To see how Pabau handles fracture code validation and clean claim workflows, book a demo with the team.

Continue your research

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