Surgical partial removal of the tibia involving craterization, saucerization, or diaphysectomy to excise diseased, infected, or necrotic bone tissue.

Verified May 8, 2026 · 6 sources ↓

Medicare: $768.55
Total RVUs: 23.01
Global, days: 90
Region: Foot & ankle

Drawn from AAPCFindacodePodiatrymPayerpriceCMS

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 the specific technique used: craterization, saucerization, or diaphysectomy — do not write 'standard debridement'
Pathology or intraoperative findings must confirm the indication (osteomyelitis, infected/necrotic bone) to distinguish 27640 from 27635
Document the anatomical location and extent of tibial bone removed, including approximate dimensions when possible
Record whether bone graft material was used to fill the defect, and specify autograft versus allograft if applicable — these may support additional codes
Pre-operative imaging (X-ray, MRI, or bone scan) establishing the extent and diagnosis of tibial involvement should be referenced in the note
Anesthesia type, patient positioning, and approach should be explicitly stated for audit completeness

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 59 Distinct service 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 6 cited references ↓

CPT 27640 covers partial excision of the tibia performed via craterization (removing bone to create a crater-shaped defect), saucerization (shaving bone to a saucer-like depression), or diaphysectomy (resecting a segment of the tibial diaphysis). The primary indication is osteomyelitis — infected or necrotic bone that must be debrided to halt spread and allow healing. The surgeon incises down to bone, excises the affected segment using curettes, osteotomes, or drills, irrigates the site, and may place bone graft material to fill the void before closure.

Critical code-selection note: If the operative indication is an exostosis or bone cyst, CPT guidelines direct you to 27635 instead. A parenthetical note under 27640 explicitly redirects exostosis excisions of the tibia or fibula to 27635, because an exostosis is classified as a benign tumor. Using 27640 for a straightforward exostosis removal is a known audit trigger. Reserve 27640 for infection-driven or necrotic bone resections.

The code carries a 90-day global period, so all routine post-operative management through day 90 is bundled. The procedure is performed in a hospital OR or ASC setting; site of service affects reimbursement meaningfully — see the Site of Service comparison table for HOPD versus ASC rates.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	11.93
Practice expense RVU	8.9
Malpractice RVU	2.18
Total RVU	23.01
Medicare national rate	$768.55
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	$768.55
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 27640 get rejected.

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

Wrong code selected: exostosis excisions billed as 27640 instead of 27635, which CPT guidelines specifically redirect
Insufficient documentation of indication — notes that say 'bone debridement' without confirming osteomyelitis or necrotic bone diagnosis
Missing operative technique specificity: notes that fail to name craterization, saucerization, or diaphysectomy as the method performed
Global period conflicts: post-operative E&M visits billed within the 90-day global without modifier 24 when the visit is unrelated, or without modifier 79 when an unrelated procedure is performed
Site of service mismatch between claim and facility billing leading to payment calculation errors

Frequently asked questions

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

01When should I use 27640 instead of 27635?

Use 27640 when the indication is osteomyelitis or infected/necrotic bone requiring craterization, saucerization, or diaphysectomy. Use 27635 when the pathology is an exostosis, bone cyst, or benign tumor — CPT includes a parenthetical note under 27640 explicitly directing exostosis cases to 27635.

02Can 27640 be billed bilaterally?

Bilateral tibial resection in a single session is unusual clinically, but if performed, append modifier 50. Document the medical necessity for bilateral disease in each operative limb separately.

03What is the global period for 27640, and what does it include?

27640 carries a 90-day global period. That covers the day before surgery, the operative day, and all routine post-op management through day 90. Unrelated E&M visits within the global window need modifier 24; an unrelated procedure needs modifier 79.

04Is bone grafting separately billable when performed with 27640?

It depends on the graft type and payer. Autograft harvest and allograft application may support additional codes, but verify NCCI bundling rules and payer policy before billing separately. Document the graft type, source site, and quantity explicitly.

05Does the location on the tibia (proximal, diaphysis, distal/malleolar) affect code selection?

27640 applies to the tibia regardless of the specific tibial segment excised. Location does not change the code, but the operative note should specify the location for audit support and to confirm the indication was infection-based rather than exostosis-based.

06Can a PCP bill for post-operative care after 27640 if the surgeon transfers care?

Yes. If the performing surgeon formally transfers post-operative care to another provider, the surgeon appends modifier 54 to 27640 and the managing provider bills modifier 55 for post-op management. Document the transfer agreement clearly — this is a known auditing scenario for this code.

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 operative technique by name (craterization, saucerization, or diaphysectomy), the confirmed indication (osteomyelitis versus exostosis), the anatomical extent of resection, and whether bone graft was placed. That specificity prevents the most common denial — miscoding an exostosis removal as 27640 when CPT guidelines require 27635 — and gives auditors the technique-level detail they look for in a 90-day global procedure.

See how Mira captures CPT 27640 documentation