Surgical reconstruction or revision of the ankle joint, typically to address post-surgical complications, joint instability, or arthritic destruction of the tibiotalar articulation.

Verified May 8, 2026 · 6 sources ↓

Medicare: $669.35
Total RVUs: 20.04
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCMdclarityPayerpriceNIH

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 identify specific structures addressed — articular surfaces, soft tissue, bone — not just 'revision of ankle'
Indication documented with prior surgical history, imaging findings, or arthritis severity supporting need for revision
Laterality (left vs. right ankle) explicitly stated in both the op note and the procedure order
Approach described by name (e.g., anterior, anterolateral, posteromedial) — audit teams flag notes that only say 'standard approach'
If modifier 22 is appended, a separate written justification detailing the additional complexity and operative time is required
Pre-operative diagnostic imaging (X-ray, CT, or MRI) on file supporting the clinical decision to revise

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 58 Staged or related 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27700 covers open ankle joint arthroplasty — a reconstructive procedure performed when the tibiotalar joint requires revision due to prior surgical failure, progressive arthritis, or significant structural compromise. The surgery may involve removing or repairing damaged articular surfaces, realigning osseous structures, addressing instability, or performing other interventions necessary to restore joint mechanics. It is distinct from primary total ankle replacement (27700 is arthroplasty/revision, not a primary implant procedure) and should not be confused with ankle arthrodesis codes.

The 90-day global period means all routine follow-up — office visits, dressing changes, hardware checks, and standard post-op management — is bundled through day 90. Any visit for an unrelated condition during that window needs modifier 24. A complication requiring a return to the OR for a related procedure uses modifier 78; an unrelated OR procedure in the global period uses modifier 79. If the revision is staged and planned as part of a multi-step treatment plan, modifier 58 applies.

Site of service matters here. HOPD and ASC payment rates differ significantly — see the site-of-service comparison table on this page. LT and RT modifiers are required when laterality is relevant, and modifier 50 applies only if bilateral ankle revision is performed in the same session, which is rare.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.42
Practice expense RVU	8.62
Malpractice RVU	2
Total RVU	20.04
Medicare national rate	$669.35
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	$669.35
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI J8) Ambulatory surgical center (freestanding)	$5,124.73

Common denial reasons

The recurring reasons claims for CPT 27700 get rejected.

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

Missing or ambiguous laterality — payer requires LT or RT modifier and denies without it
Insufficient documentation of medical necessity — no prior surgical history or imaging evidence in the record
Global period conflict — post-op visit billed without modifier 24 when an unrelated condition was treated within the 90-day global
Modifier 78 and 79 confusion — using 79 for a complication-driven return to OR (related procedure) instead of 78
Code billed in an inappropriate place of service without prior authorization, particularly for HOPD vs. ASC site discrepancies

Frequently asked questions

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

01Is 27700 the correct code for a primary total ankle replacement?

No. 27700 describes ankle arthroplasty in the revision context. Primary total ankle replacement is reported with 27702 (implant) or related codes. Confirm the specific procedure performed before selecting the code — submitting 27700 for a primary implant procedure will likely draw audit scrutiny.

02What modifier do I use if the patient returns to the OR within 90 days for a complication from the original ankle revision?

Use modifier 78 — unplanned return to the OR for a related procedure during the postoperative period. The global clock continues; it does not restart. Do not use modifier 79 for complication-driven, related returns.

03Does 27700 require prior authorization?

Most commercial payers and Medicare Advantage plans require prior authorization for ankle arthroplasty. Verify with the specific payer before scheduling — HOPD and ASC sites of service sometimes have different auth requirements for the same code.

04Can I bill an E/M visit on the same day as 27700?

Only if a separately identifiable evaluation and management service was provided for a distinct problem. Append modifier 25 to the E/M. The decision for surgery on the same day as a major procedure typically requires modifier 57 on the E/M if the decision was made that day.

05What ICD-10 diagnoses are most commonly paired with 27700?

Post-traumatic osteoarthritis of the ankle (M19.171/M19.172), primary osteoarthritis of the ankle (M19.071/M19.072), and complications of prior joint implant (T84 category codes) are the most common supporting diagnoses. The ICD-10 must align with the documented indication or the claim will mismatch on payer edits.

06If the ankle revision is performed bilaterally in the same session, how is that billed?

Report 27700 once with modifier 50 for a bilateral procedure. Some payers instead want 27700-LT and 27700-RT on separate lines — confirm the payer's preferred format before submitting, as format preference varies.

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 specific structures revised (articular surface, soft tissue, osseous alignment), the named surgical approach, laterality, and the clinical indication linking prior surgical history or imaging findings to the revision. That documentation chain is what survives a medical necessity audit — vague op notes citing only 'ankle revision' are the primary trigger for payer documentation requests on 27700.

See how Mira captures CPT 27700 documentation