Opponensplasty using a superficialis (flexor digitorum superficialis) tendon transfer to restore thumb opposition function — the ability to move the thumb across the palm to meet the fingertips.

Verified May 8, 2026 · 7 sources ↓

Medicare: $821.33
Total RVUs: 24.59
Global, days: 90
Region: Hand

Drawn from CMSAAPCMdclarityEbhmc

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Preoperative diagnosis specifying the etiology of opposition loss (e.g., median nerve palsy, thenar atrophy, post-traumatic dysfunction)
Identification of the donor tendon used — specify flexor digitorum superficialis and which digit it was harvested from
Operative note describing the routing path of the tendon transfer, pulley construction, and method of distal attachment
Intraoperative confirmation of restored passive or active opposition arc before wound closure
Postoperative splinting or immobilization plan, including position and duration, to support healing of the transfer
If modifier 22 is appended, explicit narrative in the operative note quantifying the additional complexity and time beyond the typical procedure

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 50 Bilateral procedure 51 Multiple procedures 58 Staged or related 59 Distinct service 62 Co-surgeons 76 Repeat, same physician 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 26490 describes an opponensplasty in which the surgeon reroutes a flexor digitorum superficialis tendon to reconstruct the opponens mechanism of the thumb. The goal is to restore opposition — the arc of motion that allows the thumb to oppose the fingertips — lost due to median nerve palsy, thenar muscle atrophy, trauma, or prior failed reconstruction. This is a distinct procedure from 26492, which adds a free tendon graft; 26490 uses the superficialis tendon directly without a separate graft harvest.

The 90-day global period means all routine follow-up, splinting checks, and suture removal through day 90 are bundled. Any unrelated procedure in that window needs modifier 79; a staged or planned secondary procedure needs modifier 58; an unplanned return to the OR for a related complication takes modifier 78. If significantly increased intraoperative complexity — such as dense adhesions from prior surgery — drove substantially more work, modifier 22 applies with supporting operative note documentation.

Site of service matters for this code. HOPD and ASC payments differ substantially; see the site-of-service comparison table. Bilateral opponensplasty (rare, but possible in bilateral median nerve palsy) is reported with modifier 50. When a co-surgeon participates, both surgeons append modifier 62 and each documents their distinct intraoperative role.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	8.39
Practice expense RVU	14.43
Malpractice RVU	1.77
Total RVU	24.59
Medicare national rate	$821.33
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	$821.33
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI A2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 26490 get rejected.

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

Operative note lacks specificity on donor tendon source and routing — payers flag generic 'tendon transfer' language without anatomic detail
26490 and 26492 confused at claim submission — 26492 requires a free graft harvest and is a distinct, higher-value code; miscoding triggers downcoding or denial
Services billed during the 90-day global period of a prior hand procedure without a 24, 58, 78, or 79 modifier to break the global
Modifier 22 submitted without an attached operative note narrative explaining the increased work, leading to flat denial of the add-on payment
Bilateral claim submitted without modifier 50, causing the second-thumb service to deny as a duplicate

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01What is the difference between CPT 26490 and 26492?

26490 uses the flexor digitorum superficialis tendon directly — no separate graft is harvested. 26492 adds a free tendon graft, including the graft harvest, making it a more complex and separately valued procedure. Never report both for the same thumb at the same session.

02Can 26490 be billed bilaterally?

Yes. Bilateral opponensplasty is rare but occurs in bilateral median nerve palsy cases. Bill a single line with modifier 50. Reimbursement is capped at 150% of the single-procedure rate under most payers including Medicare.

03Does the 90-day global period affect therapy or splinting follow-up?

Routine post-op visits, splint checks, and suture removal by the operating surgeon are bundled into the 90-day global. Hand therapy billed by a separate therapist is not affected. If the surgeon performs a distinct, unrelated E/M during the global, append modifier 24.

04When does modifier 58 apply versus modifier 78?

Modifier 58 covers a planned staged procedure or a return to the OR that was part of the original surgical plan — for example, a tenolysis scheduled after the transfer heals. Modifier 78 is for an unplanned return for a related complication, such as tendon rupture requiring re-attachment. Do not swap them — payers audit this distinction.

05Is a co-surgeon arrangement billable for 26490?

Yes, when two surgeons each perform a distinct, documented intraoperative role, both append modifier 62 and each submits their own claim. Each operative note must clearly define what that surgeon did. Per CMS MIPS measure guidance, both surgeons share accountability for pre-op risk assessment documentation when modifier 62 is used.

06What ICD-10 diagnoses most commonly support 26490?

Common supporting diagnoses include thenar muscle atrophy or weakness due to median nerve lesion, sequelae of carpal tunnel syndrome, and post-traumatic thumb dysfunction. The diagnosis must reflect opposition loss — not just nerve injury — to align with the procedure's clinical intent.

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 donor tendon identity (FDS, specify digit), the routing path through the pulley or constructed pulley, the distal attachment site on the thumb, and the intraoperative opposition arc achieved. That specificity prevents the generic 'tendon transfer' language that triggers payer requests for operative notes or outright downcoding to a lesser reconstruction code.

See how Mira captures CPT 26490 documentation