CPT code 23550 – Open treatment of acromioclavicular dislocation

Key takeaways

CPT code 23550 reports open treatment of an acute or chronic AC joint dislocation, repaired with internal fixation and no fascial graft.

A fascial graft moves the case to 23552, while closed care is 23540 without manipulation or 23545 with it.

Every 23550 line needs LT or RT, and the S43.1- diagnosis needs a laterality 6th character and an encounter 7th character.

CPT 29826 is an add-on to arthroscopic shoulder codes, so it never attaches to an open 23550 repair.

Commercial payers set prior authorization rules in their own medical policies, so check the plan before the case is scheduled.

CPT code 23550 covers the open repair of an AC dislocation

CPT code 23550 reports open treatment of an acromioclavicular dislocation, whether the injury is acute or chronic. AAPC’s CPT 23550 summary files it under fracture and dislocation procedures on the shoulder. It describes the repair as open treatment held with internal fixation, such as pins or screws.

The acromioclavicular (AC) joint links the acromion of the scapula to the end of the clavicle. When it dislocates, the clavicle rides up and the shoulder loses its stable strut. In a 23550 case, the surgeon opens the joint, reduces it and holds it with pins, screws, a hook plate or sutures.

The American Medical Association publishes the CPT code set, and the descriptor below is the one to match against the operative note.

Two questions decide between 23540, 23545, 23550 and 23552

The AC dislocation family splits on what the surgeon did, never on the injury grade or the patient’s age. First, was the joint opened? Then, if it stayed closed, was it manipulated, and if it was opened, was a fascial graft used?

The diagram maps those two answers to the four codes.

The operative report governs the choice. Billing 23550 when the note describes a fascial graft undercodes the case. Billing 23552 when no graft was harvested overcodes it, and that’s the version auditors look for.

What 23550 includes, and what sits outside it

Knowing the package stops two opposite mistakes: billing pieces the code already pays for, and missing work that’s reportable later. The global surgical package for 23550 covers the whole open repair episode.

• Included: Incision and exposure of the AC joint, reduction, internal fixation, wound closure and routine post-operative care in the 90-day global period.
• Not added to 23550: A fascial graft. When the surgeon uses one, the whole service becomes 23552, which includes obtaining the graft.
• Reportable later: Removal of the fixation hardware in a separate session, usually as 20680, with a global-period modifier if it falls inside the 90 days.
• Never separate: Incidental adhesion release, irrigation and routine closure layers. National Correct Coding Initiative (NCCI) edits bundle them into the primary code.

Acute or chronic, the CPT code stays 23550

CPT code 23550 covers acute and chronic dislocations under one descriptor, so the injury’s age never changes the CPT code. It changes two other parts of the claim instead: the diagnosis code, and the evidence the payer wants before surgery.

For a chronic case, the record should show why conservative care failed, such as physical therapy, activity changes or bracing. For an acute high-grade dislocation, the imaging and the documented displacement usually carry the medical necessity argument.

Acute injuries pair with S43.1- dislocation codes. A chronic, recurrent dislocation maps to M24.41- (recurrent dislocation, shoulder), or to S43.1- with the 7th character that fits the encounter.

ICD-10-CM codes that carry medical necessity for 23550

Every 23550 claim needs an ICD-10-CM code that supports open repair. The main family is S43.1-, and each code needs a laterality 6th character plus a 7th character for the encounter. The full tabular list sits in our ICD-10-CM code library.

For the S43.1- codes, the 6th character is 1 for right, 2 for left and 9 for unspecified. The surgery claim takes A for the initial encounter, and follow-up visits switch to D, as in S43.139D. Check codes against the current year in the CDC/NCHS ICD-10-CM browser.

Modifiers for 23550 start with LT or RT

Every 23550 claim needs a laterality modifier, and leaving it off is one of the quickest ways to a rejection. The table covers the modifiers that show up most on AC repair claims.

CPT 29826 can’t ride on an open 23550

No, CPT code 29826 can’t be reported with 23550. It’s an add-on code for decompression of the subacromial space with partial acromioplasty, with coracoacromial ligament release when performed. An add-on code needs a primary arthroscopic shoulder procedure, and 23550 is an open procedure.

Sometimes a surgeon does perform a separate arthroscopic procedure in the same session. In that case, 29826 attaches to that arthroscopic primary code, never to 23550. Check the CMS NCCI edit tables for the pair before you build the claim, because they’re updated every quarter.

Prior authorization depends on the plan, not the code

Whether 23550 needs prior authorization depends on the payer and the plan. Original Medicare doesn’t generally require it, while many Medicare Advantage and commercial plans do. Sound medical billing compliance means checking before the case goes on the surgery schedule, not after the claim comes back.

• Medicare: Medicare Administrative Contractors publish Local Coverage Determinations (LCDs). Where one applies, the documentation has to meet its criteria.
• Commercial plans: Each payer sets its own medical policy or utilization criteria. These often ask for imaging of a higher-grade dislocation and, for chronic cases, failed conservative care.
• The request itself: Send the CPT code, the planned date of service, the surgeon’s NPI, the operative plan and the imaging and clinical notes.
• Expiry: Confirm the authorization is still valid on the date of surgery. A rescheduled case can fall outside the approved window.

Most insurers offer a lookup by CPT code, such as the Wellcare authorization lookup, so staff can confirm the rule while booking the case.

The operative note has to prove five things

The operative report is the document that carries a 23550 claim, and the pre-op and post-op notes complete the picture. A clean claim starts with checking that each element below is in the record before anyone files.

• Pre-operative findings: Exam findings, imaging that confirms the dislocation and its displacement, and the conservative treatment history for a chronic case.
• Open approach: A clear statement that the joint was opened, with the incision and dissection described. That’s what separates 23550 from 23540 and 23545.
• Fixation: The type and configuration of the fixation, such as a hook plate, pins, screws, suture anchors or a cortical button.
• Graft status: Whether a fascial graft was harvested and used. With a graft, the case is 23552. Without one, a short statement saying so heads off a reviewer’s query.
• Medical necessity: A line linking the surgery to documented functional impairment, plus failed conservative care in a chronic case.

A worked example shows how the claim comes together

Take an illustrative case. A cyclist lands on his right shoulder, and X-rays show the clavicle displaced more than 200% compared with the other side. Ten days later, the surgeon opens the joint, reduces it and fixes it with a hook plate. No graft is taken.

• Procedure line: 23550-RT, because the joint was opened and no fascial graft was used.
• Diagnosis: S43.131A, dislocation of the right AC joint with greater than 200% displacement, initial encounter.
• Follow-up visits: Inside the 90-day global period, so they’re reported as 99024 with no charge, and the diagnosis moves to S43.131D.
• Plate removal: Billed as 20680 once it happens. Inside the global period, a removal planned at the first surgery takes modifier 58.

Change one fact and the claim changes with it. Had the surgeon harvested fascia to rebuild the joint, the whole procedure line would become 23552-RT.

Before you submit, run this six-point check

1. The note describes an open approach and no fascial graft, so 23550 is the right code.
2. LT or RT is on the line and matches the side in the note.
3. The diagnosis carries laterality in the 6th character and A in the 7th.
4. Any prior authorization is on file and valid on the date of surgery.
5. No add-on code, including 29826, is attached to the open repair.
6. Chronic cases include the conservative treatment history the payer’s policy asks for.

Most 23550 denials trace back to six errors

Nearly all of these are preventable at the front end. Good denial management treats each one as a fix to make upstream, so the next claim doesn’t repeat it.

Reimbursement for 23550 starts with Medicare RVUs

Medicare pays 23550 through the Medicare Physician Fee Schedule (MPFS). The schedule assigns the code relative value units, adjusts them for your locality and multiplies by the year’s conversion factor. The CMS Physician Fee Schedule lookup returns the current allowed amount for your area.

Third-party tools such as FastRVU’s RVU lookup show the same values in a quicker format. Rates reset every January 1, so check the effective year before you quote a figure to a patient. Commercial rates come from each payer contract, which often sets them as a percentage of the Medicare rate.

How Pabau keeps 23550 claims accurate from charge to payment

In many orthopedic practices, the surgery claim is still built by hand from the op note, the auth email and the patient’s insurance card. Each handoff is a chance to drop a modifier or key the wrong member number.

Pabau, the practice management platform we build, pre-fills the claim from the patient record. The CPT code and diagnosis codes already attached to the visit land on the claim without rekeying. Its orthopedic practice claims software checks that required fields, such as authorization numbers, are complete before the claim can be sent.

In the US, claims go out through Pabau’s Claim.MD integration, which connects to thousands of US payers. It runs real-time eligibility checks before the surgery, then tracks claim status and posts the remittance when payment arrives.

Send cleaner orthopedic surgery claims

Pabau pre-fills 23550 claims from the patient record, checks required fields before submission and tracks each claim to payment. Book a demo to see it for orthopedic and sports medicine practices.

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Conclusion

CPT code 23550 is simple to choose once the operative note answers two questions. Was the joint opened, and was a fascial graft used? Most denials on this code come from the details around that choice. Think of a missing LT or RT, an incomplete S43.1- code or an expired authorization.

So make the check routine. Code from the note rather than the surgery schedule, and run the six-point list before every AC repair claim leaves the practice. The trade-off is a few minutes per case, against weeks of rework on a denied claim.

Book a demo to see how Pabau pre-fills shoulder surgery claims and tracks every one to payment.

Continue your research

Coding a clavicle fracture instead? CPT code 23500 covers closed treatment of a clavicular fracture without manipulation.

Billing a partial AC separation? ICD-10 code S43.111A explains the right AC joint subluxation code and when it applies.

Need to track claim denials across CPT codes? What is revenue cycle management explains how end-to-end RCM workflows reduce denial rates across a practice’s code set.

Submitting surgery claims electronically? Understanding the 837 file format covers how electronic claim files are structured, including the claim frequency code.

New to the billing side of the practice? Medical billing fundamentals walks through claim submission basics that apply across the musculoskeletal CPT range.

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