ICD-10 code S82.032Q: Open left patella fracture with malunion

Key takeaways

ICD-10 code S82.032Q is a displaced transverse fracture of the left patella, subsequent encounter for open fracture type I or II with malunion.

The 7th character Q means the original fracture was open and graded Gustilo type I or II. It has since united in a malaligned position.

Malunion after a closed fracture of the same bone is S82.032P, and after a Gustilo type III wound it is S82.032R.

An open fracture documented without a Gustilo grade still takes the type I or II characters, so Q is the default open-fracture malunion code.

The note must confirm a subsequent encounter, an open wound, left laterality, and imaging evidence of malunion.

ICD-10 code S82.032Q covers a displaced transverse fracture of the left patella that healed in the wrong position. It is a subsequent-encounter code, and it applies only when the original fracture was open and graded Gustilo type I or II. The wound decides this code, not the malunion.

Three codes in this family describe the same misaligned bone, so the grade recorded at the initial encounter is the only difference between them. That grade usually sits in a trauma note from months earlier, which is where the wrong character creeps in.

What follows is the descriptor, all 16 seventh characters, the Gustilo rules, and the documentation a payer expects.

S82.032Q describes the bone, but it is graded on the wound

S82.032Q is a billable ICD-10-CM code. Its full descriptor is displaced transverse fracture of left patella, subsequent encounter for open fracture type I or II with malunion.

Three codes describe that same malunited fracture, and the wound at the time of injury is what separates them.

That detail is easy to lose by the time the patient returns for aftercare. The wound has usually closed months earlier, and the current progress note may never mention it.

ICD-10-CM still expects the 7th character to reflect how the fracture was first classified.

Because it is billable and specific, S82.032Q can stand alone on a claim without a more granular subcategory. It is also not a new code.

The S82.032 family carried the same 16 seventh-character extensions in earlier ICD-10-CM editions, and the current descriptors are published in the CMS ICD-10 code files.

Coverage and payment still follow individual payer policy, so treat what follows as coding guidance rather than a payment promise.

The patella sits in the lower-leg chapter, not with the knee

S82.032Q lives under S82, the lower-leg fracture category, because ICD-10-CM files patellar fractures with the lower leg rather than the knee joint. That surprises coders who expect to find the kneecap somewhere in the S83 range.

The hierarchy matters when documentation is thin and you have to fall back on a parent code. Each level adds one piece of specificity. Body region comes first, then the bone, then the fracture pattern, then the side, then the encounter and healing status.

One row is worth pausing over. S82.03 is titled “Transverse fracture of patella”, and it covers both the displaced codes (S82.031 to S82.033) and the nondisplaced codes (S82.034 to S82.036). So the group name alone will not tell you whether the fragments moved.

Laterality is mandatory once the chart names a side. S82.031Q covers the right patella and S82.033Q covers an unspecified patella, and there is no S82.039.

The CDC ICD-10-CM web tool walks the same hierarchy by code year, so you can confirm which extensions a parent accepts.

The 7th character carries three facts at once

Every code in category S82 needs a 7th character, and S82 uses the full 16-letter set. Each letter states whether the encounter is initial or subsequent, whether the fracture was closed or open, and how the bone healed.

Get one of those three wrong and the whole code is wrong.

The set skips I, L and O, because those letters read too easily as digits. That is why the sequence jumps from H to J and from K to M.

All 16 extensions for S82.032, side by side

Every description in the third column follows the stem “Displaced transverse fracture of left patella”.

Three pairs that look alike and code differently

• Malunion vs nonunion. Nonunion means the fragments never joined. Malunion means they joined in the wrong position. For an open type I or II fracture, nonunion is S82.032M and malunion is S82.032Q. The surgical plans differ too, since a nonunion usually needs grafting or revision fixation while a malunion may need corrective osteotomy.
• Malunion vs delayed healing. Character H applies while a type I or II open fracture is still uniting, only more slowly than expected. Once imaging shows union in a non-anatomical position, Q replaces it. Reporting H after union has been confirmed misstates the clinical picture.
• Type I or II vs type III. Q and R both describe malunion after an open fracture. The split is severity. Q covers Gustilo types I and II, and R covers types IIIA, IIIB and IIIC.

Gustilo grades five wounds, ICD-10-CM gives you two paths

ICD-10-CM collapses the five Gustilo grades into two coding paths. Types I and II share one set of characters, and types IIIA through IIIC share another. The S82 category note points to that classification, which grades the wound and the soft-tissue injury rather than the bone.

• Type I: a wound under 1 cm, clean, with minimal soft-tissue damage. Malunion takes character Q.
• Type II: a wound over 1 cm with moderate soft-tissue damage, and no extensive avulsion or flaps. Malunion takes character Q.
• Type IIIA: extensive soft-tissue damage, with enough tissue left to cover the bone. Malunion takes character R.
• Type IIIB: extensive soft-tissue loss with periosteal stripping, needing flap coverage. Malunion takes character R.
• Type IIIC: any open fracture with an arterial injury that has to be repaired. Malunion takes character R.

So five clinical grades become two coding decisions. S82.032Q is correct only when the surgeon graded the original wound as type I or type II. A type III grade anywhere in the record moves the malunion code to S82.032R.

There is a useful default here, and it works in Q’s favor. The ICD-10-CM Official Guidelines instruct coders to assign the type I or II characters when an open fracture is documented without a Gustilo grade. An ungraded open fracture that healed in malalignment therefore lands on Q, not R.

A second default points the other way, which is where coders get caught. The S82 note says a fracture not documented as open or closed is coded to closed. Silence about the wound sends the malunion to P, while an ungraded open wound sends it to Q instead.

Those two defaults pull in opposite directions, so the four documentation routes below land on only three codes.

A displaced transverse patella fracture pulls itself apart

A transverse patellar fracture runs horizontally across the kneecap, and “displaced” means the fragments have pulled out of position.

The quadriceps tendon draws the upper fragment upward, so the gap tends to widen rather than settle. Most of these injuries follow a direct blow to the front of the knee, a violent quadriceps contraction, or both.

An open version of the same injury is less common but more consequential. The patella sits directly under thin skin, so a laceration over it reaches bone quickly.

Orthopedic practices see the aftermath at follow-up, and physical therapy teams see it again through rehabilitation.

• Laterality: the note has to name the left patella. S82.031Q covers the right side and S82.033Q the unspecified side, and an unspecified code invites a records request.
• Fracture pattern: transverse is S82.032Q. Longitudinal is S82.022Q, displaced osteochondral is S82.012Q, and displaced comminuted is S82.042Q.
• Displacement: a nondisplaced transverse fracture on the left is S82.035Q. A fracture not described either way is coded to displaced, per the S82 note.
• Encounter type: Q needs the encounter to be subsequent. Definitive treatment, whether fixation or non-operative care, is already finished.

Open fractures reach malunion by a different route

Malunion is the same finding in S82.032P and S82.032Q. What differs is how the bone got there. Care for an open fracture starts with irrigation, debridement and antibiotics, and wound coverage comes first. Definitive fixation is sometimes staged days later, or held back until the soft tissue settles.

That sequence is where alignment gets lost. Contamination, periosteal stripping and a delay to fixation all work against an anatomic reduction. Repeat debridement can also cost bone stock at the fracture edges, and the extensor mechanism keeps pulling the fragments apart in the meantime.

The result matters clinically, not only on the claim. A malunited patella changes the length and the contact pattern of the extensor mechanism. Patients present with extension weakness, anterior knee pain, and a higher risk of patellofemoral arthritis later on.

Infection is the other legacy of an open fracture, and it is coded separately. The 7th character Q reports healing status only. If the visit is also treating osteomyelitis or a wound infection, that condition needs its own code.

Five confirmations before S82.032Q goes on a claim

The CMS ICD-10-CM Official Guidelines govern fracture coding across categories S52 to S82.

Five confirmations have to clear before S82.032Q goes out. Good compliance habits put that check before submission rather than after a denial.

1. Confirm the encounter is subsequent. The patient has already had definitive treatment, and this visit manages the healing result. Any encounter involving active treatment of the fracture itself takes A, B or C.
2. Confirm the original fracture was open. The trauma or operative note has to describe the open wound, and ideally grade it. An ungraded open wound still takes the type I or II characters, so Q stands.
3. Rule out a type III wound. A documented type IIIA, IIIB or IIIC wound moves the malunion code to S82.032R. Read the grade from the original note, not from the current appearance of the scar.
4. Confirm malunion. The note must state malunion, or imaging must show union in a non-anatomical position with the clinician endorsing that reading. Symptoms on their own are not enough.
5. Confirm laterality and add secondary codes. Query the provider if the side is ambiguous. Code related conditions separately, such as post-traumatic osteoarthritis of the knee that follows the malunion.

The S82 tabular notes that bind this code

The tabular notes at the S82 category level bind every code beneath it, S82.032Q included. Four of them affect this code directly.

• Includes: fracture of malleolus. The category covers the ankle alongside the patella and the tibia.
• Excludes1: traumatic amputation of lower leg (S88.-). Never report S82.032Q with an S88 code for the same encounter.
• Excludes2: fracture of foot except ankle (S92.-). The note also excludes periprosthetic fractures around an internal prosthetic ankle joint (M97.2) or a knee implant (M97.1-). A patellar fracture around a knee implant is reported with M97.1- instead.
• Defaults: a fracture not documented as displaced or nondisplaced is coded to displaced, and one not documented as open or closed is coded to closed.

Two more habits keep these claims clean. Do not add a separate S81.- open wound code for the wound that the 7th character already describes. Do add an external cause code from V00-Y99 where the mechanism matters, which it usually does for workers’ compensation and liability claims.

Four of five components is still an incomplete note

Most S82.032Q denials trace back to a note that supports four of the five code components. Run this checklist before the claim goes out:

• The date of the original injury, and how this visit relates to it.
• The wound description and Gustilo grade from the initial trauma or operative report.
• The definitive treatment already delivered, with dates.
• Current imaging showing union in a non-anatomical position.
• A clinician statement of malunion, in those words wherever possible.
• Left laterality in the narrative, not only on an image label or an order.
• Any planned revision procedure, which supports medical necessity for what follows.

The claim passes through four hands before it pays

Knowing the code is one job. Getting it paid is another, and it helps to picture the route the claim takes.

1. The clinician documents the visit. Today’s note carries the malunion finding and the imaging that supports it.
2. The coder pulls the second record. The 7th character comes from the original trauma or operative report, so that note has to be within reach.
3. Billing builds the claim. S82.032Q sits as the reason for the visit, alongside the procedure or evaluation code for what was performed.
4. The clearinghouse scrubs it, then the payer adjudicates. Format problems bounce back in hours, while medical-necessity questions come back weeks later as a denial.

Stage two is where most of the trouble starts. If the trauma note lives in a hospital system the practice cannot search, the coder either queries the provider or guesses. Guessing usually means defaulting to closed, and the claim goes out as S82.032P.

The diagnosis is also only half the claim. The visit carries a procedure or evaluation code too, and the CPT code library lists the patellar revision options that pair with a malunion.

Five mistakes that put S82.032Q on the wrong claim

These five come up again and again on S82.032 malunion claims. Each one has a fix that takes less time than an appeal.

1. Coding from today’s note alone. The current note rarely mentions a wound that closed months ago, so the claim drifts to S82.032P. Open the original report first.
2. Reading the scar instead of the record. A healed type III wound can look unremarkable at follow-up. Only the recorded grade decides between Q and R.
3. Leaving H in place after union. Delayed healing becomes malunion the moment imaging confirms union in a bad position. Update the character at that visit.
4. Switching to an initial-encounter character for revision surgery. B and C cover active treatment of the original fracture. Surgery aimed at the malunion keeps Q.
5. Falling back to the unspecified side. S82.033Q is for a chart that genuinely never names a side. If the note says left, use S82.032Q.

Twelve codes sit one character from S82.032Q

Each code below is a malunion version of the same injury, so only the wound grade, the side or the fracture pattern changes. Every one of them differs from S82.032Q by a single character.

Cross-check any of them in the AAPC ICD-10-CM lookup.

Reading down the third column shows how independently the parts move. The pattern digit, the laterality digit and the 7th character each control one fact, and each one can be wrong on its own.

ICD-9-CM recorded almost none of this detail

All that specificity is recent. Legacy systems and older registries that still reach back to ICD-9-CM lose most of it. An open patellar fracture mapped to 822.1, and malunion of a fracture mapped to 733.81. Aftercare for a healing traumatic fracture of the lower leg sat at V54.16.

None of those codes recorded the side, the Gustilo grade or the fracture pattern. That is the practical reason S82.032Q reads the way it does. It is also why auditors expect the note to support each part of it separately.

Why malunion claims draw a second look

Malunion claims draw attention because the 7th character is easy to get wrong and hard to defend afterwards. Running the claim through a clearinghouse catches the mechanical problems first. Formatting errors and incomplete code combinations get flagged before the payer ever sees them.

The rest is documentation. Practices with orthopedic volume gain more from a clean first pass than from appealing later. Tracking reason codes across a quarter also tells you more than any single appeal, which is where denial management earns its keep.

Check the relevant MAC local coverage determinations too, since some name the diagnosis codes that support medical necessity for fracture aftercare.

How Pabau keeps the 7th character right from chart to claim

Coding an open-fracture malunion means reading two notes at once. The 7th character depends on a trauma or operative report that may be months old, while the malunion finding sits in today’s imaging. When those records live in separate systems, coders spend their time hunting instead of coding.

Practice management software like Pabau keeps them in one patient record. Pabau’s medical claims management puts ICD-10-CM entry inside the clinical workflow, so the coder and the clinician work from the same chart.

Diagnoses entered at the point of care carry through to billing without re-entry, which is where 7th character mismatches usually creep in.

Submission runs through the Claim.MD clearinghouse to thousands of US payers, with real-time eligibility checks and remittance processing built in. Billing teams can see where a claim stands without chasing it. A rejected 7th character then surfaces in days, not at the end of the month.

For a practice running fracture aftercare alongside everyday billing, one system holds the note, the diagnosis and the claim. That removes the handoffs that produce 7th character mismatches.

Keep the 7th character right from chart to claim

Pabau connects ICD-10-CM entry, clinical notes and claims submission in one record, so fracture aftercare codes reach the payer with the documentation behind them. See how it works for orthopedic and physical therapy practices.

Book a demo

Conclusion

S82.032Q rests on three confirmations. The encounter is subsequent, the original fracture was open and graded type I or II, and the bone united in a malaligned position. Change the wound status and the code changes with it, to S82.032P for a closed fracture or S82.032R for a type III wound.

The safeguard is unglamorous and it works. Read the original trauma note before you assign the 7th character, and make sure today’s note states the malunion in plain words. Do that and the claim carries its own defense into an audit.

Most of the work here is keeping two notes within reach of one coder. Book a demo to see how Pabau holds the trauma note, the diagnosis and the claim in a single record.

Continue your research

Need guidance on ICD-10-CM coding compliance for your practice? Medical billing compliance covers documentation standards, audit readiness, and how to avoid common claim errors.

Want to see how clearinghouse submission reduces fracture coding denials? Claim.MD clearinghouse integration explains how electronic claims validation works before the claim reaches the payer.

Looking for a complete overview of medical billing workflows? What is medical billing breaks down every stage of the billing cycle from diagnosis coding to payment posting.

Frequently asked questions