ICD-10 code S52.021R: Right olecranon fracture with malunion

Key takeaways

ICD-10 code S52.021R covers a displaced fracture of the olecranon process of the right ulna, without intraarticular extension.

The 7th character R marks a subsequent encounter for an open type IIIA, IIIB, or IIIC fracture that healed with malunion.

Laterality lives in the sixth character. A 1 is the right ulna, a 2 is the left ulna, and a 3 means the side was never documented.

A malunion after an open type I or II fracture takes Q instead. A closed malunion takes P.

Character M is not malunion. It reports nonunion after an open type I or II fracture, and mixing the two misstates the healing status.

If the fracture line reaches the elbow joint, the code moves to the S52.03 family, so the right-side equivalent becomes S52.031R.

Practice management software like Pabau keeps the diagnosis code attached to the note it came from.

ICD-10 code S52.021R is a billable ICD-10-CM diagnosis code for an elbow fracture seen after active treatment has finished. Its full description is a displaced fracture of the olecranon process without intraarticular extension of the right ulna.

The 7th character R carries the rest of the story. It marks a subsequent encounter for an open type IIIA, IIIB, or IIIC fracture with malunion.

Every element of that description does work. The fracture is displaced, so the bone fragments have shifted out of alignment. It sits in the olecranon process at the tip of the elbow, and the fracture line stops short of the joint surface.

The injury is on the right side. It was open at Gustilo type III severity on the day it happened. At this visit the bone has united in a faulty position, which is malunion.

Two characters decide most of this code. The sixth character fixes the side, and the 7th character fixes the encounter, the open grade, and the healing state. The CDC/NCHS ICD-10-CM web tool confirms S52.021R as a valid, billable code under the current tabular list.

Code details at a glance

Use the table below to check S52.021R before a claim goes out. Every field in it has to match the clinical record, not just the code description.

What each part of the S52.021R descriptor means

Every phrase in this descriptor maps to a fact that has to sit in the record. Misreading one of them downcodes the claim or invites a query. Here is what each component means for documentation and billing.

• Displaced: the fracture fragments have shifted out of anatomical alignment. Displacement has to be confirmed on imaging. A nondisplaced fracture on the same side is S52.024 instead.
• Olecranon process: the bony prominence at the tip of the elbow, formed by the proximal ulna. It anchors the triceps tendon and forms the posterior wall of the elbow joint.
• Without intraarticular extension: the fracture line does not reach the elbow joint surface. A fracture that does reach it belongs to the S52.03 subcategory, which makes the right-side displaced code S52.031.
• Right ulna: the sixth character carries laterality. A 1 is the right ulna, a 2 is the left, and a 3 covers an undocumented side. So the left-side equivalent here is S52.022R.
• Subsequent encounter: active treatment for the fracture has finished. This is a follow-up visit, not the visit where the injury was first fixed.
• Open fracture type IIIA, IIIB, or IIIC: the skin was breached at the time of injury, at the most severe Gustilo-Anderson grades.
• Malunion: the fracture has united, but in a faulty position. Nonunion is the opposite picture, where union never happened at all.

According to the CMS ICD-10-CM coding guidelines, every component of a fracture code has to be supported by the clinical documentation. A claim billed as S52.021R with no malunion statement in the note is exposed at audit. Practices working from structured clinical documentation tools can require those fields in the follow-up template.

Anatomy of the olecranon process

The olecranon process is the curved projection of the proximal ulna that sits behind the elbow joint. With the coronoid process it forms the trochlear notch, which articulates with the humerus. That joint gives the elbow its hinge motion.

When the olecranon fractures, the triceps pulls the proximal fragment upward. That is why displaced patterns are the common presentation here. Two questions then decide the code. Does the fracture line cross into the joint, and have the fragments moved out of alignment?

Both answers belong in the imaging report, not in the coder’s judgment. Practices managing elbow injuries across several visits often run sports medicine software to keep that detail attached to the case.

How the 7th character works in the S52.02 group

The 7th character is the densest part of this code. It records the encounter, whether the fracture was open or closed, and how the bone has healed. R means subsequent encounter, open type IIIA to IIIC, with malunion.

The S52.02 subcategory has 16 characters available. The letters I, L, and O are never used, because they read too easily as digits. The grid below is the fastest way to land on the right letter.

Read the grid in threes and the pattern gets easy. Each healing state has one closed character and two open ones, split at Gustilo type II. Malunion runs P, Q, and R, so R is the severe open option.

The letter M trips up more claims here than any other. M looks like shorthand for malunion, but it reports nonunion after an open type I or II fracture. Nothing on the claim form flags the swap, and the payer sees a healing state the note does not support.

Gustilo classification and the character it drives

The Gustilo-Anderson system grades open fractures by wound size, contamination, and soft tissue coverage. ICD-10-CM uses that grade to choose between the two open characters in each healing state. S52.021R applies only when the original wound was type IIIA, IIIB, or IIIC.

The surgeon assigns the grade, never the coder. Practices running documentation compliance checks can flag any operative note that records an open fracture with no grade. That query costs far less before submission than after a denial.

One rule saves most of these claims. The grade is set at the injury and carries forward unchanged, so a follow-up visit never re-grades the wound.

Malunion, nonunion, and delayed healing in the S52.021 family

These three healing states look alike in a chart and take three different characters. The treating provider decides which one applies, and the coder follows that statement.

Malunion means the fracture has united, but in a faulty position. The bone ends have joined and the alignment is wrong. That is the state S52.021R reports.

Nonunion means the fracture never united within the expected timeframe, usually judged at six months or more. Delayed healing means union is still progressing, only slower than expected. Neither one has the healed-but-crooked picture that malunion describes.

Swap the type III grade for a closed fracture and the same four states become D, G, K, and P, as S42.256P shows. An open type I or II fracture uses E, H, M, and Q in the same order. Nonunion at that milder grade lands on the letter M, which is what S82.232M reports.

The note has to name the finding. Language such as “fracture callus present in malposition” supports malunion. “Fracture gap persists, no bridging callus” supports nonunion. A vague line like “fracture not healing well” supports neither and invites a query.

Adjacent and related codes in the S52.02 group

S52.021R sits in the S52.02 subcategory, which covers olecranon fractures without intraarticular extension. The codes nearest to it each differ by one variable. Knowing which variable moved makes the right pick obvious.

The AAPC Codify ICD-10-CM lookup confirms a descriptor and its fiscal year before a claim goes out. The same malunion logic at a milder open grade runs through S72.452Q. Teams with claims tracking in one system also spot a run of sibling-code denials early.

S52.021R in the ICD-10-CM code hierarchy

Walking the hierarchy shows why a shorter code will not do. Each level adds one clinical fact, and only the 7th character produces a submittable code.

• S00-T88 – Chapter 19, injury, poisoning and certain other consequences of external causes
• S50-S59 – Injuries to the elbow and forearm
• S52 – Fracture of forearm
• S52.0 – Fracture of upper end of ulna
• S52.02 – Fracture of olecranon process without intraarticular extension of ulna
• S52.021 – Displaced fracture of olecranon process without intraarticular extension of right ulna
• S52.021R – Subsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunion

Note the two codes that reject on their own. S52.02 has no laterality or displacement, and S52.021 has no 7th character. Both are header codes rather than billable diagnoses.

Follow-up for an olecranon malunion usually runs across several settings. Surgical review, imaging, and rehabilitation visits all need the same 7th character. That means the healing status has to be current in the note every time.

Approximate synonyms and clinical terms

Dictated notes rarely use tabular wording. The phrases below all describe the presentation that S52.021R reports, and none of them appears verbatim in the tabular list.

• Malunion of a displaced right olecranon fracture, previously open at type III
• Extra-articular right olecranon fracture, healed in malalignment
• Right olecranon process fracture, Gustilo grade IIIA, angular deformity after union
• Malunited displaced fracture of the olecranon process of the right ulna, follow-up encounter
• Right elbow tip fracture, open type IIIB, united in a faulty position
• Displaced right olecranon fracture sparing the joint surface, malunion on follow-up radiographs

Three terms look like synonyms and code elsewhere. An olecranon fracture that extends into the joint surface belongs to S52.03, which makes the right-side displaced code S52.031. A coronoid process fracture codes to S52.04. A radial head fracture sits in the S52.1 group, even when the note calls it an elbow fracture.

A bare “right elbow fracture” is the fourth trap. That phrase could mean the distal humerus in the S42.4 group instead of the ulna. A segmental fracture further down the same ulna is S52.261R. Query the site before assigning anything in S52.02.

Sequencing rules for a subsequent fracture encounter

Follow-up fracture care has its own sequencing conventions in the ICD-10-CM Official Guidelines. Getting them wrong rejects orthopedic claims even when the fracture code itself is right.

• Do not use an aftercare Z code for fracture follow-up, and report the injury code with a subsequent-encounter 7th character instead
• Sequence the fracture code first, then any external cause code from Chapter 20 as a secondary code
• Carry the Gustilo grade documented at the injury forward to every later encounter
• Keep laterality identical across encounters, because a switched side reads as a new injury
• Reserve S52.021S for a late effect, and code the residual condition first

Some state rules and payer contracts require external cause reporting, so check what applies locally. A closed malunion follows the same conventions with a different letter, as S42.012P shows.

Documentation requirements for S52.021R

Six facts have to appear in the record before this code is safe to assign. Miss one and the coder either queries the provider or drops to a less specific code.

• Laterality: documented as the right ulna, not just the right elbow
• Fracture site: the olecranon process, with a statement that the line does not extend into the joint
• Displacement: confirmed as displaced rather than nondisplaced on imaging
• Open fracture grade: Gustilo type IIIA, IIIB, or IIIC, recorded by the treating surgeon at the injury
• Encounter type: a follow-up visit after active fracture treatment has finished
• Healing status: malunion stated by the provider, not inferred from an imaging report

The cheapest place to fix this is the first encounter. Custom clinical forms can require the side, the displacement, and the open fracture grade before a note can be signed. Every later visit then inherits facts a coder would otherwise chase.

Present on admission (POA) indicators

Inpatient hospital claims usually need a POA indicator on each diagnosis code, and a subsequent-encounter code behaves differently here. The original injury happened at an earlier encounter, so the indicator reflects the current admission rather than the injury date.

If the admission is for corrective surgery on the malunion, the malunion was present on admission. POA rules vary by payer and by state Medicaid program, so confirm the requirement before submission. Most outpatient claims need no POA indicator at all, and S52.021R is billed mainly in outpatient orthopedic follow-up.

ICD-9-CM crosswalk

For legacy claims and audit defense, the closest ICD-9-CM equivalent is 813.11, open fracture of olecranon process of ulna. The similar-looking 813.01 is the closed fracture code, so it does not fit the open injury that S52.021R reports. Mixing the two is a common error in retrospective reviews.

ICD-9-CM never carried this much detail. Laterality, displacement, Gustilo grade, and healing complication were not coded separately, which is why one ICD-9 code maps to dozens of ICD-10-CM codes. General Equivalence Mappings from CMS remain the authoritative source for that conversion.

CPT codes commonly paired with this diagnosis

A documented malunion brings either corrective surgery or continued follow-up. The procedures below are the ones that most often appear on a claim alongside this diagnosis.

A diagnosis code never justifies a procedure code on its own. Payer edits still test whether the operative note supports the work billed, so check each contract. Orthopedic practices that scrub claims before submission catch most of these mismatches in-house.

Common coding errors to avoid

Five mistakes account for most inaccurate S52.021R claims. Each one is catchable in the chart before submission.

1. Reading the laterality digit backwards

This is the error worth checking first. In the S52.02 subcategory a sixth character of 1 is the right ulna and 2 is the left. A right-side malunion is therefore S52.021R, and S52.022R would put the injury on the wrong arm. When the side was never documented, S52.023R is the unspecified option.

2. Choosing M because the note says malunion

M is nonunion after an open type I or II fracture, despite the way the letter reads. Malunion after a type III open injury takes R. The two characters describe opposite healing states, so this swap misrepresents the whole encounter.

3. Coding an intraarticular fracture to S52.02

S52.02 is the without intraarticular extension subcategory, so it never fits a fracture that reaches the joint surface. When the operative note describes joint involvement, the right-side malunion code is S52.031R. Read the imaging report rather than the diagnosis line.

4. Using a routine healing character on a confirmed malunion

Characters D and F report a fracture healing on schedule. Once malunion is documented, the code moves to P for a closed injury or R for a type III open one. Billing a routine follow-up when the note states malunion is a mismatch a payer can see.

5. Using a subsequent character at an initial visit

R describes a follow-up encounter. It cannot report the visit where the fracture is first treated, debrided, or fixed. Those encounters take a character from the A to C range. C covers an open type IIIA to IIIC injury, and B covers the milder open grades, as S72.041B shows.

Each of these five is a documentation problem before it is a coding problem. A coder who can see the injury record and the follow-up note on one screen avoids all five.

How Pabau keeps subsequent-encounter coding accurate

In most orthopedic practices the fracture detail and the claim live in different systems. A coder reads the operative report, finds the Gustilo grade, then retypes a code into a billing screen. Each retype is another chance to lose a character.

Practice management software like Pabau closes that handoff. The clinician records the fracture in a structured note, and the diagnosis code selected there travels with the claim. Nobody reconstructs the original grade from a discharge summary months later.

That matters on a code like S52.021R, where one letter separates malunion from nonunion and one digit separates right from left. Required form fields can hold laterality, displacement, and open fracture grade from the first visit onward. Your team raises a query that week instead of working a denial next quarter.

Keep fracture codes tied to the clinical note

Pabau holds laterality, displacement, and open fracture grade in structured notes, then carries the diagnosis code your clinician selects through to the claim.

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Conclusion

S52.021R rewards practices that get the first operative note right. When the record names the side, the displacement, the joint involvement, and the Gustilo grade, the follow-up code follows in seconds.

Two traps sit inside this code. A sixth character of 2 moves the injury to the left arm, and the letter M reports nonunion rather than malunion. Neither error looks wrong on a claim form, and both surface at audit.

So build those four facts into the fracture template and let every later code inherit them. Book a demo to see how Pabau keeps diagnosis codes attached to the documentation they came from.

Continue your research

Need the same malunion logic at a milder open grade? S72.452Q covers a distal femur malunion after an open type I or II fracture.

Coding a failed union instead? S72.334N shows how character N reports nonunion after a type III open fracture.

Working a closed malunion? S42.012P applies character P to a clavicle fracture that healed out of position.

Need the sequela character instead? S82.036S shows how character S reports a late effect once fracture treatment has ended.

Coding a nonunion on a smaller bone? S62.630K applies the nonunion character in a family that carries no open fracture grades.

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