Ankle arthroscopy with surgical excision of an osteochondral defect of the talus and/or tibia, including drilling of the subchondral bone when performed.

Verified May 8, 2026 · 6 sources ↓

Medicare: $633.95
Total RVUs: 18.98
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCCoderoncallAAOSAoassn

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Confirm laterality (left vs. right ankle) — required for LT/RT modifier assignment
Specify location of the osteochondral defect: talus, distal tibia, or both
Document the size and depth of the lesion in the operative note
State whether drilling was performed and describe the technique (e.g., microfracture awl, drill)
Record portals used and arthroscopic findings with cartilage grading
If 29894 is also billed, document that the loose body required portal enlargement or a separate incision to remove — state the cannula size comparison explicitly
Confirm the procedure was not a conversion to open; arthroscopic approach must be maintained throughout to support 29891

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 59 Distinct service LT Left side RT Right side 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 29891 covers arthroscopic surgery on the ankle to excise an osteochondral defect involving the talar dome, the distal tibia, or both. The surgeon accesses the joint arthroscopically, identifies the cartilage lesion, debrides the damaged tissue, and drills into the underlying subchondral bone to stimulate healing. Per the November 2023 CPT Knowledge Base clarification, drilling is included when performed — it is not required to report this code. The code descriptor's language reflects what the procedure encompasses, not a prerequisite checklist.

This procedure carries a 90-day global period under CMS. All routine post-op visits, dressing changes, and stitch removals within that window are bundled. Services unrelated to the osteochondral repair billed during the global period require modifier 24 (E/M) or 79 (unrelated procedure). A return to the OR for a complication directly tied to the original repair uses modifier 78.

NCCI guidelines govern what can be co-reported on the same ankle on the same day. Under Medicare, codes 29897 and 29898 (limited and extensive debridement) cannot be billed separately alongside 29891 — this differs from CPT guidelines, which impose no such restriction. Loose body removal (29894) is separately reportable only when the body requires a larger cannula or a distinct portal enlargement; the operative note must explicitly document that threshold 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	9.43
Practice expense RVU	7.98
Malpractice RVU	1.57
Total RVU	18.98
Medicare national rate	$633.95
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	$633.95
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 29891 get rejected.

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

Missing laterality — payer rejects claim without LT or RT modifier
29897 or 29898 co-billed on same ankle same day under Medicare, triggering NCCI edit denial
29894 added for loose body removal without documentation that a larger cannula or enlarged portal was required
Insufficient medical necessity documentation — ICD-10 diagnosis code does not support osteochondral defect repair (e.g., osteoarthritis-only diagnosis without osteochondral lesion)
Post-op visit billed without modifier 24 during the 90-day global period
Operative note describes defect location generically without specifying talus versus tibia — payer flags as incomplete documentation

Frequently asked questions

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

01Does drilling have to be performed to bill 29891?

No. The November 2023 CPT Knowledge Base clarified that drilling is included when performed, not required. You can report 29891 for excision of the osteochondral defect even if drilling was not done.

02Can 29897 or 29898 be billed with 29891 on the same ankle?

Not under Medicare. NCCI edits prohibit reporting 29897 or 29898 separately alongside another ankle arthroscopy code on the same ankle on the same date. CPT guidelines do not carry this restriction, but Medicare NCCI controls for Part B claims.

03When is modifier 59 needed with 29891?

Use modifier 59 — or its X{S} subset if your payer requires granular modifiers — when co-billing a procedure that is ordinarily bundled with 29891 but was performed as a distinct service. Confirm the NCCI edit status of each co-billed code before applying 59 to override it.

04Can 29894 (loose body removal) be billed with 29891?

Only if the loose body was large enough to require a cannula larger than the one used for 29891, or required portal enlargement or a separate incision. The operative note must document the cannula size discrepancy or the distinct portal used. Without that documentation, 29894 will be denied or recouped.

05What ICD-10 codes support 29891 for medical necessity?

Osteochondral defect or osteochondritis dissecans of the ankle — typically coded under M93.271/M93.272 (OCD, ankle and joints of foot, right/left) or M93.279 (unspecified). A diagnosis of osteoarthritis alone (M19.07x) without a documented osteochondral lesion is unlikely to satisfy medical necessity review for this code.

06What happens if the surgeon converts from arthroscopic to open during the same session?

Report only the open procedure code. Per NCCI arthroscopy guidelines, when a surgeon converts to an open approach, the arthroscopic component is not separately reportable — bill the open osteochondral repair code that reflects what was completed.

07Is a bilateral ankle procedure billable under 29891?

Bilateral ankle osteochondral repair in one session is uncommon but reportable. Use modifier 50 if billed on a single line, or LT and RT on separate lines per payer preference. Verify individual payer policy, as some commercial payers require separate lines rather than 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 defect location (talus, tibia, or both), lesion size and depth, whether drilling was performed and the instrument used, portal documentation, and cannula size if a loose body was addressed. This detail directly prevents the two most common 29891 audit flags: a vague operative note that omits talus-versus-tibia distinction, and an unsupported 29894 add-on when loose body removal isn't separately documented to meet the portal-enlargement threshold.

See how Mira captures CPT 29891 documentation