Surgical flexor-plasty of the elbow with additional extensor advancement, performed to improve elbow flexion strength and function.

Verified May 8, 2026 · 6 sources ↓

Medicare: $734.15
Total RVUs: 21.98
Global, days: 90
Region: Elbow

Drawn from CMSFastrvuEmednyCgsmedicareMedicaid

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Operative report must identify 24331 by explicitly documenting both the flexor-plasty and the extensor advancement components — notes that describe only 'Steindler-type' advancement without documenting the extensor advancement step support 24330, not 24331.
Document the pre-operative functional deficit (loss of elbow flexion strength/range, underlying etiology such as cerebral palsy, brachial plexus injury, or post-traumatic contracture) to establish medical necessity.
Record the surgical approach, muscle origins addressed, extent of advancement in centimeters or anatomical landmarks, and any tendon graft use if applicable.
Post-operative immobilization plan and rehabilitation protocol should appear in the operative or discharge note to support the global period management.
If performed under a regional or general anesthetic by a separate anesthesiologist, confirm the attending surgeon's note does not document anesthesia services — split billing requires accurate provider identification.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 24 Unrelated E/M during global 25 Significant separate E/M 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 57 Decision for surgery 58 Staged or related 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 6 cited references ↓

CPT 24331 describes an elbow flexor-plasty that includes extensor advancement — a more involved reconstruction than the base Steindler-type procedure (24330). The surgery repositions the flexor-pronator muscle origin to increase the mechanical advantage of elbow flexion, and the extensor advancement component adds reconstructive complexity that distinguishes this code from its companion.

The 90-day global period covers all routine pre- and post-op care through day 90. Any E/M service on the day of surgery performed solely to decide whether to operate should be billed with modifier 57. Unrelated procedures or returns to the OR after the initial case follow modifier 79 (unrelated) or 78 (related, unplanned) rules respectively.

Site of service matters here: HOPD and ASC payments differ substantially — see the Site of Service comparison table on this page. When billing bilateral elbow procedures in the same session, append modifier 50 and confirm payer policy on bilateral reimbursement caps (typically 150% of the single-procedure allowable for Medicare).

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	10.68
Practice expense RVU	9.03
Malpractice RVU	2.27
Total RVU	21.98
Medicare national rate	$734.15
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	$734.15
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI J8) Ambulatory surgical center (freestanding)	$4,682.29

Common denial reasons

The recurring reasons claims for CPT 24331 get rejected.

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

Code billed as 24331 when operative note only supports the base flexor-plasty (24330) — extensor advancement must be explicitly documented, not implied.
Medical necessity denied when the indication is not clearly tied to a diagnosable functional deficit; vague diagnoses such as 'elbow weakness' without an underlying etiology are frequently rejected.
Global period violations — E/M or follow-up visits billed within the 90-day window without modifier 24 (unrelated visit) or 25 (significant separate service on day of procedure).
Bilateral billing without modifier 50 or incorrect line-item duplication instead of single-line bilateral reporting per payer requirements.
Prior authorization not obtained for facility-based elective reconstructive procedures, particularly common with commercial payers for non-traumatic indications.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What separates 24331 from 24330?

24330 covers the base Steindler-type flexor-plasty alone. 24331 adds extensor advancement to that reconstruction. If your operative note doesn't document the extensor advancement as a performed component, bill 24330.

02Can I bill 24331 and 24330 together on the same elbow?

No. They are mutually exclusive for the same elbow — 24331 is the more comprehensive code that already incorporates the flexor-plasty element. Billing both together on the same side will trigger an NCCI bundling denial.

03What modifier applies if an E/M visit on the day of surgery was used to make the decision to operate?

Modifier 57 applies when a same-day E/M was the visit at which the decision for a major surgical procedure (90-day global) was made. Append 57 to the E/M code, not to 24331.

04How do I bill an unplanned return to the OR for a complication related to the original flexor-plasty?

Use modifier 78 on the return-to-OR procedure code. Modifier 78 signals an unplanned return for a related complication during the global period. Do not use modifier 79, which is reserved for unrelated procedures.

05Does 24331 carry a bilateral modifier consideration?

Bilateral elbow flexor-plasty in the same session is rare but codeable. Append modifier 50 to 24331 on a single claim line. Medicare typically reimburses bilateral procedures at 150% of the single-procedure allowable — confirm your payer's bilateral policy before submitting.

06What ICD-10 diagnoses most reliably support medical necessity for 24331?

Diagnoses tied to a functional motor deficit — such as sequelae of brachial plexus injury, post-polio syndrome, cerebral palsy with upper limb involvement, or post-traumatic elbow contracture with documented flexion weakness — anchor medical necessity. Nonspecific musculoskeletal codes without a documented functional deficit invite denial.

07Is prior authorization typically required for 24331?

Medicare does not require prior authorization for 24331, but most commercial and Medicaid managed care plans treating elective reconstructive elbow procedures will. Confirm before scheduling; denials for missing auth are rarely overturned on appeal.

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 extensor advancement component directly from dictation — the specific muscles advanced, the degree of repositioning, and the functional indication — ensuring the operative note distinguishes 24331 from the base 24330. This prevents downcoding on audit when reviewers look for explicit documentation of both the flexor-plasty and the extensor advancement to justify the higher-complexity code.

See how Mira captures CPT 24331 documentation