Open surgical repair of an osteochondral defect on the talus using autograft tissue harvested from the patient's own body during the same operative session.

Verified May 8, 2026 · 6 sources ↓

Medicare: $1,125.61
Total RVUs: 33.7
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCGenhealthMdclarityFindacode

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Operative note must name the open approach and confirm direct visualization of the talar defect
Document defect size (diameter and depth in mm) and location on the talar dome (medial, central, or lateral)
Identify the donor/harvest site by anatomic location — typically non-weight-bearing zone of the ipsilateral knee
Pre-operative imaging (MRI or CT) in the chart confirming the osteochondral defect extent
Record prior failed conservative treatment (duration, modalities) to support medical necessity
Confirm graft preparation steps and fixation method used in the body of the operative report

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity LT Left side RT Right side 51 Multiple procedures 76 Repeat, same physician 77 Repeat, another physician 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 28446 covers open osteochondral autograft of the talus, the primary ankle bone, including harvest of the graft from a donor site — typically a non-weight-bearing region of the ipsilateral knee. The surgeon makes an open incision at the ankle, debrides the damaged cartilage and subchondral bone, shapes the autograft plug to match the defect geometry, and press-fits or fixes it into place. Because graft harvest is bundled into this code, you cannot separately bill a harvesting code.

The procedure targets symptomatic osteochondritis dissecans (OCD) or full-thickness chondral defects of the talus that have failed conservative management. Typical ICD-10 supports include M93.271–M93.279 (OCD of ankle and joints of foot) and M94.271–M94.279 (chondromalacia of ankle). Confirm lesion size, location on the talar dome, and failed prior treatment in the medical record — payers use these to justify medical necessity.

The 90-day global period covers all routine post-op care through day 90. Any unrelated procedure billed in that window requires modifier 79. An unplanned return to the OR for a related complication — graft failure, wound dehiscence — uses modifier 78. Document the donor site separately in the operative note; auditors will look for it since the code description explicitly includes graft procurement.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	17.27
Practice expense RVU	12.76
Malpractice RVU	3.67
Total RVU	33.7
Medicare national rate	$1,125.61
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	$1,125.61
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI J8) Ambulatory surgical center (freestanding)	$4,775.23

Common denial reasons

The recurring reasons claims for CPT 28446 get rejected.

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

Medical necessity not established — no documentation of failed conservative management prior to surgery
Missing or vague donor site documentation; payers flag notes that omit harvest site details since graft procurement is bundled into 28446
ICD-10 code mismatch — billing a knee OCD diagnosis (M93.26x) against a talar procedure code
Unbundling error — separately billing a graft harvest code that is already included in 28446
Laterality not specified on the claim; absence of LT or RT modifier triggers edits from many commercial payers

Frequently asked questions

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

01Is graft harvest billed separately when using 28446?

No. The code description explicitly includes obtaining the graft. Billing a separate harvest code alongside 28446 is an unbundling error and will be denied or recouped on audit.

02Which modifier indicates this was performed on the left ankle?

Use modifier LT for the left ankle or RT for the right. Many commercial payers require a laterality modifier on foot and ankle surgery codes; missing it is a common clean-claim failure point.

03What ICD-10 codes best support 28446 for a talar OCD lesion?

M93.271–M93.279 (osteochondritis dissecans, ankle and joints of foot) and M94.271–M94.279 (chondromalacia of ankle) are the primary supports. Match the laterality digit to the operative side.

04Can 28446 be billed with an ankle arthroscopy on the same day?

If arthroscopy is performed as a separate, distinct service — for example, diagnostic scope followed by open autograft — append modifier 51 to the lower-valued code. However, if the scope is simply used to confirm defect location immediately before the open procedure, payers often bundle it. Document the separate clinical purpose explicitly.

05What applies if the patient returns to the OR during the 90-day global for graft-related failure?

Use modifier 78 for an unplanned return to the OR for a procedure related to the original surgery within the global period. Modifier 79 is reserved for procedures unrelated to the original surgery — do not swap them.

06Does the site of service affect reimbursement for 28446?

Yes. The HOPD and ASC payment rates differ meaningfully — see the Site of Service comparison on this page. Because of the 90-day global, where you perform the case also affects whether post-op facility fees flow back to the surgeon's global or are separately payable by the facility.

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 talar defect location (medial vs. lateral dome), defect dimensions in millimeters, donor harvest site anatomy, fixation technique, and the surgeon's statement of prior failed conservative therapy — all from intraoperative dictation. That prevents the two most common 28446 denials: missing harvest-site documentation and unsupported medical necessity.

See how Mira captures CPT 28446 documentation