Surgical fusion of the subtalar joint, eliminating motion between the talus and calcaneus to treat post-traumatic arthritis, degenerative arthritis, or hindfoot deformity.

Verified May 8, 2026 · 7 sources ↓

Medicare: $729.14
Total RVUs: 21.83
Global, days: 90
Region: Foot & ankle

Drawn from CMSAAPCMedicalpolicyFindacodePodiatrym

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Specify the diagnosis driving the fusion — post-traumatic arthritis, degenerative arthritis, Charcot arthropathy, or hindfoot deformity — with supporting imaging.
Document cartilage resection and preparation of both joint surfaces down to subchondral bone.
Identify the fixation method by name and implant type (e.g., cannulated screws, staple, hindfoot intramedullary nail).
Record fluoroscopic confirmation of alignment and hardware position intraoperatively.
If bone graft was used, document graft source (autograft vs. allograft) and harvest site with separate incision detail if applicable.
Confirm the operative note names the subtalar joint explicitly — notes referencing only 'hindfoot fusion' without specifying the joint are an audit flag.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 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

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 28725 describes arthrodesis of the subtalar joint — the articulation between the talus and calcaneus. The surgeon resects cartilage down to subchondral bone, achieves alignment, and provides rigid fixation (typically screws, staples, or an intramedullary nail) to promote bony union across the joint. Indications include post-traumatic arthritis following calcaneus fractures, primary osteoarthritis, adult-acquired flatfoot deformity, and Charcot arthropathy of the hindfoot.

Carries a 90-day global period. All routine follow-up, wound checks, and stitch removal through day 90 are bundled — bill unrelated E/M services with modifier 24. When subtalar arthrodesis is performed together with ankle arthrodesis (27870) using a hindfoot nail, both codes are reportable; document each joint surface separately in the operative note. Do not confuse this code with subtalar arthroereisis (implant limiting motion without fusion): arthroereisis is reported with S2117 or 0335T — billing 28725 for an arthroereisis procedure is a misrepresentation and will trigger audit scrutiny.

For multi-joint hindfoot fusion sessions (e.g., adding talonavicular 28730 or naviculocuneiform arthrodesis), each joint is coded separately with modifier 51 on the secondary procedure. Bone graft harvest performed through a separate incision may be separately reportable; confirm payer policy.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	10.94
Practice expense RVU	9.04
Malpractice RVU	1.85
Total RVU	21.83
Medicare national rate	$729.14
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	$729.14
HOPD (APC 5115) Hospital outpatient department	$13,116.76
ASC (PI J8) Ambulatory surgical center (freestanding)	$9,367.96

Common denial reasons

The recurring reasons claims for CPT 28725 get rejected.

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

Operative note documents subtalar arthroereisis (implant limiting motion) rather than true joint fusion — wrong code, not a modifier fix.
Missing conservative treatment failure documentation prior to surgical intervention.
Bundling denial when 28725 is billed same-day with ankle arthrodesis 27870 without adequate separate joint documentation.
Modifier 51 omitted on secondary arthrodesis when multiple foot joints are fused in the same session.
Global period violation — routine post-op visit billed without modifier 24 within the 90-day window.

Frequently asked questions

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

01Can I bill 28725 for a subtalar arthroereisis implant procedure?

No. Arthroereisis limits joint motion without fusing it — that is a fundamentally different procedure. Use S2117 or 0335T (for HyProCure). Billing 28725 for an arthroereisis is a misrepresentation and exposes the practice to audit recovery.

02If I perform subtalar and ankle arthrodesis together using a hindfoot nail, do I bill both 28725 and 27870?

Yes, both are reportable when both joint surfaces are resected and fused. Document each joint preparation separately in the operative note. AHA Coding Clinic guidance supports reporting both codes in this scenario.

03What modifier applies when billing 28725 with other foot arthrodesis codes in the same session?

Append modifier 51 to the secondary procedure(s). For example, if you also fuse the talonavicular joint (28730) in the same session, 28730 gets modifier 51.

04Is bone graft separately billable with 28725?

Local bone graft taken through the same incision is bundled. Graft harvested through a separate incision — such as iliac crest autograft — may be separately reportable; verify with the payer before billing.

05What is the global period for 28725 and what does it include?

The global period is 90 days. It covers the day-before visit, the procedure, and all routine post-op care through day 90. Bill unrelated E/M visits with modifier 24 and unrelated procedures with modifier 79.

06What ICD-10 diagnoses support medical necessity for 28725?

Common supporting diagnoses include M19.071/M19.072 (primary osteoarthritis, ankle/foot), M12.571/M12.572 (traumatic arthropathy), M14.671/M14.672 (Charcot arthropathy), and sequelae of calcaneus fractures. Imaging confirming joint space loss or deformity strengthens the record.

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 joint surfaces prepared, fixation hardware used, graft source and harvest site, fluoroscopic alignment confirmation, and the named surgical approach from dictation — all details auditors check first. That prevents the most common 28725 denial: an operative note that describes implant placement (arthroereisis) instead of true bony fusion, or one that omits explicit identification of the subtalar joint.

See how Mira captures CPT 28725 documentation