Prophylactic fixation of the proximal humerus using nails, plates, screws, or similar implants, with or without methylmethacrylate bone cement, to prevent pathologic fracture or structural failure.

Verified May 8, 2026 · 8 sources ↓

Medicare: $937.56
Total RVUs: 28.07
Global, days: 90
Region: Shoulder

Drawn from CMSBedrockbillingFastrvuEmednyAAPC

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 8 cited references ↓

Specify fixation device(s) used: nail, plate, screw, or other implant hardware by name
State explicitly whether methylmethacrylate bone cement was or was not used
Document the clinical indication — metastatic lesion, primary tumor, osteopenia, or other pathology creating fracture risk
Include imaging correlation (X-ray, CT, or MRI) demonstrating the structural defect or lesion at the proximal humerus
Record laterality (left vs. right shoulder) in both the operative report and the claim
If modifier 22 is appended, quantify the additional work and explain why it exceeded the typical procedural effort

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 58 Staged or related 59 Distinct service 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 8 cited references ↓

CPT 23491 covers prophylactic reinforcement of the proximal humerus — the upper end of the arm bone at the shoulder — using internal fixation hardware such as nails, plates, or screws. Methylmethacrylate bone cement may or may not be used to augment stability. The procedure is performed to prevent impending or pathologic fracture, typically in the setting of metastatic disease, primary bone tumors, or severe osteopenic bone at risk of structural failure. It is categorized under Repair, Revision, and/or Reconstruction of the Shoulder.

The 90-day global period means the surgery day, the day-before visit, and all routine postoperative management through day 90 are bundled into the single payment. Unrelated E/M visits or procedures during that window require modifier 24 or 79, respectively. The code carries a 28.07 total RVU under the CMS Physician Fee Schedule 2026, and the significant site-of-service payment differential between HOPD and ASC settings makes facility selection a meaningful revenue variable.

Bilateral prophylactic reinforcement of both humeri at the same session is unusual but not impossible; append modifier 50 if that occurs. When significantly increased operative complexity is documented — for example, extensive tumor involvement, prior hardware, or abnormal anatomy requiring additional time and technique — modifier 22 is appropriate, but the operative note must quantify the added work to survive audit.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	14.18
Practice expense RVU	10.87
Malpractice RVU	3.02
Total RVU	28.07
Medicare national rate	$937.56
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$937.56
HOPD (APC 5115) Hospital outpatient department	$13,116.76
ASC (PI J8) Ambulatory surgical center (freestanding)	$9,085.46

Common denial reasons

The recurring reasons claims for CPT 23491 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Missing or vague indication — payers require documented evidence of impending fracture risk, not just bone abnormality
Laterality not specified on the claim when LT or RT modifier is required by the payer
Bundling conflict when ancillary procedures performed at the same site are billed without a valid NCCI modifier
Modifier 22 appended without operative note documentation quantifying the increased complexity
Global period violations — postoperative E/M visits billed without modifier 24 within the 90-day window

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01What distinguishes 23491 from standard proximal humerus fracture repair codes?

23491 is a prophylactic procedure — the bone hasn't fractured yet. It's used when fixation is placed preemptively to prevent an impending or pathologic fracture, not to treat an acute fracture. Acute fracture repairs bill under the 23600–23680 range depending on treatment type.

02Is methylmethacrylate required to bill 23491?

No. The code includes 'with or without methylmethacrylate.' Document its use or non-use explicitly — auditors look for that language. Omitting it creates ambiguity about whether a more complex procedure was performed.

03Can 23491 be billed with a shoulder arthroscopy on the same day?

Only if the arthroscopy addresses a genuinely distinct condition at a different anatomic site or the procedures are otherwise non-overlapping. Check the NCCI PTP edit table for the specific code pair before appending modifier 59. Per CMS NCCI policy, contiguous structures in the same region are not automatically considered separate anatomic sites.

04Which ICD-10 diagnoses support medical necessity for 23491?

Metastatic bone disease to the humerus (e.g., C79.51), primary malignant bone tumors, and pathologic fracture risk codes are the most defensible. Payers will scrutinize claims without a diagnosis code that explicitly conveys structural compromise or malignant involvement of the proximal humerus.

05How does the 90-day global period affect billing for oncology follow-up?

Oncology follow-up visits during the 90-day global are only separately billable if they address the underlying cancer management — not the surgical wound or hardware. Append modifier 24 and document that the visit was unrelated to normal postoperative recovery. Payers will audit E/M claims in the global window.

06Should 23491 be reported bilaterally with modifier 50 or on two separate claim lines?

Bilateral prophylactic humerus fixation is rare, but if performed, append modifier 50 to a single line per CMS billing convention. Medicare caps reimbursement at 150% of the single-procedure allowable for bilateral procedures billed with modifier 50.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the implant type and brand, whether methylmethacrylate was used, the specific proximal humerus anatomy involved, and the pathologic indication from the surgeon's dictation. That detail prevents the most common denial on this code — a claim rejected for insufficient medical necessity documentation when the operative note only says 'reinforcement performed' without tying hardware selection to the underlying lesion or fracture risk.

See how Mira captures CPT 23491 documentation