Arthroscopic surgery of the subtalar joint with removal of damaged tissue, debris, or diseased cartilage from below the ankle.

Verified May 8, 2026 · 7 sources ↓

Medicare: $625.93
Total RVUs: 18.74
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCNIH

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Specify portal placement by name (posterolateral, posteromedial, anterolateral subtalar) in the operative note
Describe the pathology identified: synovitis, chondral damage, fibrous tissue, loose bodies, or other intra-articular findings
Document tissue and structures debrided with anatomic specificity — do not use generic language such as 'routine debridement'
Record pre-operative conservative treatment failure: duration, modalities tried (PT, orthotics, injections), and clinical response
Include fluoroscopic or scope images in the operative record where available to corroborate intra-articular findings
Confirm laterality (left or right subtalar joint) in both the operative report and the claim

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 58 Staged or related 59 Distinct service 62 Co-surgeons 74 Discontinued post-anesthesia 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side XS Separate structure

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 29906 covers a surgical arthroscopy of the subtalar joint — the articulation between the talus and calcaneus, just below the ankle — during which the surgeon debrides damaged tissue, cartilage fragments, synovitis, or other intra-articular debris. The procedure is performed with a small-caliber arthroscope and instruments introduced through portal incisions at the posterior or anterolateral subtalar approach. Indications include subtalar arthrofibrosis, post-traumatic arthritis, synovitis, chondral lesions, and os trigonum-related pathology.

The 90-day global period means routine post-op visits, wound checks, and suture removal through day 90 are bundled. A new, unrelated problem evaluated during that window requires modifier 24 on the E/M. NCCI policy bundles diagnostic arthroscopy into the surgical arthroscopy — don't report 29900 alongside 29906 for the same joint at the same encounter. Local anesthetic injection for the procedure is also not separately billable.

Subtalar arthroscopy is a low-volume, technically demanding procedure. Many commercial payers require documented failure of conservative management (physical therapy, orthotics, corticosteroid injections) before authorizing the case. Operative notes must name the portal placement, specific pathology encountered, and tissue removed — vague operative language like 'debridement performed' without anatomic specificity is a common audit target.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.41
Practice expense RVU	7.74
Malpractice RVU	1.59
Total RVU	18.74
Medicare national rate	$625.93
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	$625.93
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI G2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 29906 get rejected.

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

Lack of medical necessity documentation — payer requires evidence of failed conservative treatment before authorizing subtalar arthroscopy
Operative note too vague: 'debridement performed' without specifying tissue type, anatomic location, or extent triggers medical necessity audits
Laterality modifier missing (LT or RT absent) — many payers auto-deny foot-ankle arthroscopy without side designation
Bundling with diagnostic arthroscopy (29900) billed same-day, same joint — diagnostic scope is included in the surgical code
Post-op E/M billed without modifier 24 during the 90-day global period, causing automatic denial for the office visit

Frequently asked questions

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

01Can I bill 29900 (diagnostic arthroscopy) alongside 29906 when the surgeon starts with a diagnostic look before proceeding to debridement?

No. NCCI policy bundles diagnostic arthroscopy into any same-joint surgical arthroscopy performed at the same encounter. Report only 29906.

02What modifier do I use if the surgeon performs 29906 on both subtalar joints at the same session?

Append modifier 50 for a bilateral procedure billed on a single line, or use LT and RT on separate lines depending on payer preference. Confirm with the specific payer — some commercial plans require separate lines.

03Is 29906 covered for subtalar arthritis without mechanical symptoms?

Payer policies vary. Most require documented failure of conservative management. Pure osteoarthritic pain without mechanical symptoms is the harder case to get approved — mirror the language from your LCD or payer policy in the clinical notes.

04How does the 90-day global affect post-op visits?

All routine post-op visits within 90 days are bundled. If you see the patient for an unrelated condition (e.g., a new injury or a different diagnosis) during the global, bill the E/M with modifier 24 and document that the visit was unrelated to the surgical procedure.

05Can I separately bill a corticosteroid injection into the subtalar joint at the same session as 29906?

A local anesthetic injection to facilitate the procedure is not separately billable per NCCI. A distinct therapeutic steroid injection into a different structure may be reportable with modifier 59 or XS if documented as a separate, medically necessary service — but confirm with the payer before billing.

06What if the surgeon performs microfracture of the subtalar joint at the same time as debridement — is there a separate code?

There is no standalone CPT code for subtalar microfracture. If the procedure goes significantly beyond standard debridement, modifier 22 with a detailed operative note explaining the increased work and time is the appropriate path to capture additional reimbursement.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures portal placement, structures visualized, specific pathology (synovitis grade, chondral lesion location and size, fibrous tissue extent), tissue debrided, and fluoroscopy use — directly from surgeon dictation. That detail satisfies the operative specificity auditors look for in subtalar arthroscopy claims and prevents denials tied to vague documentation of debridement.

See how Mira captures CPT 29906 documentation