Arthroplasty of the temporomandibular joint using autogenous graft material harvested from the patient, performed to restore jaw function.

Verified May 8, 2026 · 6 sources ↓

Medicare: $943.58
Total RVUs: 28.25
Global, days: 90
Region: Other

Drawn from CMSAAPCEmednyMdclarityCgsmedicare

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Diagnosis driving surgical necessity — specify condition (e.g., TMJ ankylosis, degenerative joint disease, post-traumatic arthritis) with ICD-10 code linked to the procedure
Confirmation that autogenous graft was used and the anatomic harvest site documented (distinguishes 21240 from 21242 allograft and 21243 prosthetic replacement)
Operative note describing the extent of joint resection, graft shaping, and fixation — generic 'standard approach' language is an audit flag
Pre-operative imaging (CT or MRI) demonstrating structural joint pathology sufficient to justify open arthroplasty over less invasive options
Documentation of conservative treatment failure (e.g., splint therapy, physical therapy, injections) if payer requires exhaustion of non-surgical options prior to authorization
For modifier 22 claims: operative note must explicitly state increased operative time, extent of adhesion or scar excision, or other complexity factors beyond the typical case

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 24 Unrelated E/M during global 25 Significant separate E/M 58 Staged or related 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 21240 covers surgical reconstruction of the temporomandibular joint (TMJ) using the patient's own graft tissue — harvested at the same operative session — to repair, reposition, or replace damaged joint components. The procedure addresses structural failure of the TMJ caused by degenerative joint disease, trauma, ankylosis, or prior failed TMJ surgery. Graft harvest is included in the code; do not bill a separate graft-harvest code.

The code sits within the Repair, Revision, and/or Reconstruction Procedures on the Head section and carries a 90-day global period. All routine pre- and post-operative care through day 90 is bundled. Separate E/M visits within that window require modifier 24 (unrelated) or modifier 25 (significant, separately identifiable — day-of, pre-op only). For the closely related 21242 (allograft) and 21243 (prosthetic joint replacement), confirm graft source before submitting; payers audit graft-type mismatches aggressively on this family of codes.

Bilateral TMJ reconstruction at the same session is reported with modifier 50. Increased complexity — severe ankylosis, revision after prior arthroplasty, extensive scar excision — supports modifier 22, but the operative note must quantify the added time and difficulty explicitly. The procedure is performed almost exclusively by oral and maxillofacial surgeons; orthopedic billers encounter it most often when managing multi-specialty claims or cross-coverage scenarios.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	15.67
Practice expense RVU	10.48
Malpractice RVU	2.1
Total RVU	28.25
Medicare national rate	$943.58
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	$943.58
HOPD (APC 5165) Hospital outpatient department	$6,048.05
ASC (PI A2) Ambulatory surgical center (freestanding)	$3,025.62

Common denial reasons

The recurring reasons claims for CPT 21240 get rejected.

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

Wrong graft-type code billed — submitting 21240 when allograft (21242) or prosthetic implant (21243) was actually used triggers medical-record audits and downcoding
Lack of prior-authorization: most commercial payers and many Medicaid plans require PA for TMJ arthroplasty; claims submitted without it are denied on technical grounds regardless of clinical merit
ICD-10 mismatch — TMJ pain codes alone (e.g., M79.1x) do not justify open arthroplasty; structural diagnosis codes (M26.6x series, S03.0x for dislocation/fracture) are required
E/M visit billed within the 90-day global period without modifier 24 or 25, causing automatic bundling denial
Separate graft-harvest code billed alongside 21240 — harvest is included in the procedure descriptor and is not separately payable

Frequently asked questions

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

01How does 21240 differ from 21242 and 21243?

Graft source determines the code. 21240 = autogenous graft (patient's own tissue, harvest included). 21242 = allograft (donor tissue). 21243 = prosthetic joint replacement. Submitting the wrong code based on operative findings is the most common error in this code family.

02Can I bill separately for harvesting the autograft?

No. The code descriptor explicitly includes obtaining the graft. Billing a separate harvest code alongside 21240 will be denied as unbundling.

03Is 21240 payable by Medicare?

Medicare covers TMJ arthroplasty when medical necessity criteria are met, but TMJ procedures are a known coverage exclusion under some Medicare Advantage plans and many commercial policies. Verify plan-specific TMJ coverage and prior-authorization requirements before scheduling.

04How do I bill bilateral TMJ arthroplasty performed at the same session?

Report 21240 once with modifier 50. Some payers instead want 21240-LT and 21240-RT on separate lines — check the payer's bilateral billing instructions before submitting.

05What supports a modifier 22 on this code?

Revision after prior TMJ surgery, severe fibrous or bony ankylosis requiring extensive takedown, or significantly prolonged operative time. The operative note must state the specific complicating factors and document extra time — a vague reference to 'difficult anatomy' will not survive audit.

06What is the global period for 21240, and what does it cover?

21240 carries a 90-day global period under the CMS Physician Fee Schedule 2026. The global includes the day-before pre-op visit, the procedure itself, and all routine post-operative care through day 90. Unrelated E/M services in that window need modifier 24; a significant separately identifiable E/M on the day of surgery needs modifier 25.

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 graft source and harvest site from dictation, the specific joint pathology addressed, and the operative approach and fixation technique — the three elements auditors check first on 21240 claims. That documentation directly prevents down-coding to 21242 or 21243 and supports modifier 22 when complexity is dictated but not quantified in a generic note.

See how Mira captures CPT 21240 documentation