ICD-10 Code S43.111A: Right AC joint subluxation guide

Key takeaways

ICD-10 code S43.111A covers subluxation of the right acromioclavicular (AC) joint at an initial encounter, and it is billable for FY2026.

S43.11 and S43.111 are non-billable parent codes, so a claim needs the 7th character that turns S43.111 into S43.111A.

The 7th character A, D, or S records the encounter phase, and choosing the wrong one is a frequent denial trigger.

ICD-10 grades AC dislocation by displacement percentage, but it never grades subluxation, so S43.111A carries no severity detail at all.

Practice management software like Pabau helps a practice attach the right diagnosis code and catch missing 7th-character detail before submission.

ICD-10 code S43.111A is a billable diagnosis code for subluxation of the right acromioclavicular (AC) joint at an initial encounter. Subluxation means the joint surfaces are partly displaced but still touching. The 7th character A confirms the patient is under active treatment for the injury.

This reference covers the code’s full description, its 7th character options, sibling codes, laterality rules, documentation requirements, and the CPT codes it usually travels with.

Subluxation and dislocation of the AC joint sit in two different subcategories, and the codes look almost identical on screen. ICD-10 grades one of them by displacement percentage and leaves the other ungraded. That asymmetry drives most of the misassignments in this family, so it is worth reading the two apart before anything else.

ICD-10 code S43.111A: Definition and billable status

ICD-10 code S43.111A is a valid, billable ICD-10-CM diagnosis code effective for FY2026 (October 1, 2025, through September 30, 2026). Its full official description is: Subluxation of right acromioclavicular joint, initial encounter.

Coders can verify current validity using the CDC/NCHS ICD-10-CM web tool, which reflects each fiscal year’s official tabular list.

What subluxation of the right acromioclavicular joint means

The acromioclavicular joint connects the clavicle (collarbone) to the acromion process of the scapula. It stabilizes the shoulder girdle and is vulnerable to downward force on the shoulder, such as a direct fall or a contact sport impact.

A subluxation is a partial displacement of the joint surfaces. Unlike a full dislocation, the joint keeps some articular contact, but ligamentous integrity is disrupted. The code title carries no severity qualifier, so a Rockwood grade recorded in the note does not change the code you submit.

• Right: the injury involves the right shoulder’s AC joint specifically
• Subluxation: partial displacement, with the joint surfaces still in contact
• Initial encounter: the patient is receiving active treatment for this injury

Approximate synonyms accepted under this code include right AC joint subluxation, right shoulder AC joint subluxation, and partial dislocation of the right acromioclavicular joint.

How to choose the 7th character: A, D, or S

The 7th character is mandatory for every code in the S43 injury category. Choosing the wrong character is one of the most common denial triggers for musculoskeletal trauma claims. The CMS ICD-10 codes guidance under Section I.C.19 of the Official Guidelines confirms the three valid options for traumatic injury codes.

One rule settles most disputes here. The 7th character reflects the patient’s encounter phase rather than the provider’s specialty. A physical therapist seeing a patient for a third session still uses D while treatment is active. Once the injury has resolved and the patient returns with a residual complaint, S applies.

Where S43.111A sits in the S43 category

Two levels above S43.111A are non-billable. Submitting S43.11 or S43.111 without the 7th character will produce a rejection. The full hierarchical path is:

• S00-T88: Injury, poisoning and certain other consequences of external causes
• S40-S49: Injuries to the shoulder and upper arm
• S43: Dislocation and sprain of joints and ligaments of shoulder girdle
• S43.1: Subluxation and dislocation of acromioclavicular joint (non-billable)
• S43.11: Subluxation of acromioclavicular joint (non-billable)
• S43.111: Subluxation of right acromioclavicular joint (non-billable, needs a 7th character)
• S43.111A: Subluxation of right acromioclavicular joint, initial encounter (billable)

The same A, D, and S convention runs through the whole S00-T88 chapter, including sprains of the lumbar spine and pelvis such as S33.8XXS. For a broader lookup, the AAPC Codify ICD-10-CM lookup displays the full S43 family with billable status indicators.

All billable child codes under S43.11

Choosing between right, left, and unspecified laterality

ICD-10-CM requires laterality specificity for paired anatomical structures. The AC joint is a paired structure, so the unspecified-side code S43.119A only fits when the record genuinely cannot confirm the affected shoulder. An illegible note or a telehealth consult without a physical exam are the usual examples.

In practice, most clinical documentation confirms the side. Using S43.119A when laterality is documented is a coding error that payers may flag on audit. The same trap runs through fracture coding, where S32.416A covers an acetabulum fracture with no side recorded.

Manual therapy practices see AC joint injuries regularly, so capturing the side at intake pays for itself. Chiropractic software and osteopathy practice software both support required fields on the intake form, which stops an unspecified-side code from reaching the claim.

Subluxation vs dislocation: Why the codes diverge

Subluxation and dislocation of the AC joint sit in separate subcategories under S43.1, and the difference is more than a word. Dislocation means complete loss of articular contact, while subluxation means partial displacement.

ICD-10-CM treats the two with very different levels of detail. Dislocation gets graded by displacement, with separate codes for 100%-200% displacement (S43.12) and for more than 200% displacement (S43.13). Subluxation gets no grading at all, so S43.111A is the whole answer for a right-sided partial displacement.

That asymmetry has a practical consequence. If a radiologist reports displacement percentages, the provider still has to name the finding as a dislocation or a subluxation. Only one of those two words unlocks the graded codes, as the subsequent-encounter code S43.139D shows.

The provider’s documentation has to use specific clinical language. “AC joint injury” on its own is not enough. Coders need the note to say subluxation, dislocation, or sprain before they can pick the right S43 subcategory. The open fracture code S32.492B makes the same demand in a different body region.

When to use S43.111A: Three clinical scenarios

Three common presentations lead to this code. Each one needs the provider note to confirm the same three elements. Those are the right side, subluxation rather than sprain or dislocation, and an encounter for active treatment.

• Direct fall on the shoulder: a cyclist or skier lands on the right shoulder, driving the acromion downward. Imaging shows a widened AC joint space without full separation. The ED note reads “right AC joint subluxation.” Code: S43.111A.
• Contact sport tackle: a football player takes a downward force on the right shoulder. Sports medicine evaluation confirms partial displacement of the right AC joint at first presentation. Code: S43.111A.
• Outstretched hand fall: a patient falls on an outstretched arm, sending force up through the shoulder. Exam and X-ray confirm right AC subluxation at the first visit for this injury. Code: S43.111A.

If the same patient returns two weeks later for follow-up physical therapy, the treating provider switches to S43.111D. When that patient presents six months later with chronic shoulder instability traced to the original injury, S43.111S applies.

One detail trips up therapy billing. The diagnosis code moves to D once treatment is no longer initial. The therapist’s own first evaluation still bills as an initial evaluation, such as 97161. The two “initials” answer different questions, so they do not have to agree.

Documentation requirements for S43.111A

Four elements must appear in the clinical record to support ICD-10 code S43.111A on a claim. Miss any one of them and the code is unsubstantiated.

• Laterality confirmed: the note must say “right shoulder,” “right AC joint,” or an equivalent. Left-side documentation with a right-side code is a mismatch.
• Subluxation specificity: the provider must write “subluxation” or “partial dislocation.” Terms like “AC joint injury,” “shoulder pain,” or “shoulder sprain” do not map to S43.111A.
• Initial encounter context: the note or visit type must show active treatment rather than follow-up or sequela care. First presentations, emergency evaluations, and urgent care visits for new injuries all qualify.
• Imaging or exam findings: ICD-10-CM does not strictly require them, but most payers expect supporting evidence. An X-ray report noting a widened AC joint space or stress views strengthens medical necessity.

Practices using digital intake forms can capture laterality and mechanism of injury at registration. The detail is then already in the chart when the coder reaches it.

Those four elements repeat across the injury chapter, and the finger wound code S61.223A shows how granular they can get. On record retention and handling, HIPAA compliance covers what has to stay on file and for how long.

Associated CPT codes for acromioclavicular joint subluxation

S43.111A is a diagnosis code, so it has to be paired with the right CPT procedure codes on the claim. The table below lists the pairings that come up most often. Payer policy and medical necessity criteria always govern, and none of these pairings is universally accepted without review.

Closed treatment codes 23540 and 23545 name dislocation, not subluxation, which is why payers scrutinize them against an S43.11 diagnosis. The AAPC CPT-to-ICD-10 crosswalk helps confirm the medical necessity link before the claim goes out.

How Pabau supports AC joint injury coding workflows

AC joint coding errors usually start upstream of the coder. The side is missing from the note, or the provider wrote “AC joint injury” instead of “subluxation.” Sometimes nobody recorded whether this visit was the first one for the injury. By the time a claim is built, the detail has to be chased back through the chart.

Practice management software like Pabau moves that capture to the point of care. Intake forms and clinical note templates can make laterality, injury mechanism, and encounter type required fields, so nothing reaches billing half-documented. Every subscription includes those tools, so a smaller practice gets the same setup as a multi-site group.

From there, our claims management software keeps diagnosis codes tied to the encounter that supports them and tracks claim status after submission. The outcome is fewer coder queries, fewer denials on 7th-character detail, and faster payment on straightforward shoulder injuries.

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Conclusion

AC joint subluxations are straightforward to treat, yet they generate coding errors far more often than that simplicity suggests. Getting S43.111A right comes down to three checks. Confirm the documented side, the word “subluxation” in the provider’s own note, and the 7th character for the encounter phase. Miss one and the claim either fails or comes back as a query.

The codes that look closest to S43.111A are the ones to watch. S43.101A is a dislocation, S43.51XA is a sprain, and S43.201A belongs to the sternoclavicular joint entirely. Build the three checks into the note template rather than the coder’s memory, and the whole family stops being a denial risk. To see how Pabau keeps diagnosis codes, encounters, and claims tied together, book a demo.

Continue your research

Need to document the shoulder exam behind the diagnosis? Yocum test walks through how to perform, interpret, and compare a shoulder impingement test.

Coding a clavicle injury that has already healed? S42.032S shows how the sequela character works on a displaced lateral clavicle fracture.

Working on late effects in the shoulder and upper arm? S48.922S shows how a sequela claim reads elsewhere in the same S40-S49 section.

Billing plain-film imaging for a joint injury? 73521 covers how view counts and laterality drive what a radiology claim pays.

Building out your orthopedic special test library? Tight hip flexors test shows how to record a positive finding so it supports the code you submit.

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