Below-knee amputation through the tibia and fibula with immediate prosthetic fitting technique, including application of the first cast.

Verified May 8, 2026 · 6 sources ↓

Medicare: $758.87
Work RVU: 13.13
Global, days: 90
Region: Foot & ankle

Drawn from AAPCMdclarityFindacodeAAOSCMS

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 specify the immediate fitting technique and explicit application of a rigid cast for prosthetic preparation — absence of this detail triggers reclassification to 27880.
Document the indication by name: vascular insufficiency, diabetic peripheral angiopathy with gangrene, osteomyelitis, trauma, or other qualifying diagnosis.
Record the level of bone transection through both tibia and fibula and describe skin flap closure technique.
Laterality must be documented (right vs. left leg) to support LT/RT modifier appended to the claim.
If modifier 22 is used for increased complexity (e.g., severely infected or necrotic field), the operative note must quantify the additional work and time.
Decision-for-surgery visit on the day of or day before the procedure requires modifier 57 on the E/M code; document that the surgical decision was made at that encounter.

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 50 Bilateral procedure 51 Multiple procedures 57 Decision for surgery 58 Staged or related 76 Repeat, same physician 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 27881 describes a transtibial (below-knee) amputation performed through both the tibia and fibula, distinguished from the standard BKA code (27880) by the immediate fitting technique: the surgeon applies a rigid cast at closure specifically designed to accommodate early prosthetic fitting. This cast-and-fit approach is a deliberate surgical decision that must be documented in the operative note — it's what separates 27881 from 27880 and is the single most common reason auditors reclassify the code.

The 90-day global period covers the surgery, the day-before visit if a decision for surgery was not made that day, and all routine post-op care through day 90. Prosthetic evaluation and fitting by a separate provider (orthotist/prosthetist) is not included in the surgeon's global and is billed independently. Stump revision during the 90-day global for complications requires modifier 78. A planned staged revision or re-amputation requires modifier 58 and resets the global clock.

Indications are typically vascular insufficiency, diabetic gangrene, trauma, or osteomyelitis. ICD-10 diagnosis coding must reflect the underlying condition driving the amputation — a missing or generic diagnosis is the primary cause of medical necessity denials on this code. Post-procedure, the acquired absence code (Z89.51x) applies to subsequent encounters, not the operative encounter.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (13.13) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (22.72) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	13.13
Practice expense RVU	6.41
Malpractice RVU	3.18
Total RVU	22.72
Medicare national rate	$758.87
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	$758.87
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 27881 get rejected.

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

Claim billed as 27881 but operative note describes standard skin flap closure without immediate cast application — payer downcodes to 27880.
Missing or nonspecific ICD-10 diagnosis fails medical necessity criteria; a generic 'leg pain' code will not support amputation.
Laterality modifier (LT or RT) absent, triggering claim suspension or rejection at clearinghouse.
Post-op E/M billed without modifier 24 during the 90-day global period for a visit that was not clearly unrelated to the amputation.
Staged revision billed with modifier 78 instead of 58, or vice versa — payers audit the return-to-OR scenario carefully on amputation cases.

Frequently asked questions

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

01What separates 27881 from 27880?

The immediate fitting technique. If the surgeon applies a rigid cast at closure specifically to prepare the stump for early prosthetic fitting, bill 27881. Standard skin-flap closure without that cast is 27880. The operative note must name the technique — auditors use that language to validate the code selection.

02When is 27882 (guillotine amputation) the right code instead?

Use 27882 when the leg is amputated but the wound is intentionally left open — no skin flap closure. Guillotine amputations are staged; the open stump is closed at a later date. If closure occurs at a subsequent encounter, code that separately with modifier 58.

03Can 27881 be billed bilaterally?

Yes, but bilateral below-knee amputation at a single operative session is rare. If it occurs, append modifier 50 or use LT and RT on separate line items per payer preference. Expect significant documentation scrutiny — prior auth requirements apply at most commercial payers.

04What modifier applies if a stump revision is needed during the 90-day global?

Modifier 78 if the return to the OR is for a complication related to the original amputation (e.g., wound dehiscence, infection requiring debridement). Modifier 79 if the new procedure is genuinely unrelated. Do not use 58 for complications — 58 is for planned staged procedures.

05Does the surgeon's global include prosthetic fitting visits?

No. The prosthetist or orthotist bills independently for fitting and device delivery. What the 90-day global does cover is the surgeon's routine post-op stump checks, suture removal, and cast changes. Prosthetic evaluation by the surgeon that goes beyond routine post-op care can be billed separately with modifier 24.

06What ICD-10 codes are typically paired with 27881?

Common pairings include E11.51 (type 2 DM with diabetic peripheral angiopathy without gangrene), E11.52 (with gangrene), I70.261–I70.269 (atherosclerosis of native arteries with gangrene), and traumatic or osteomyelitis codes depending on indication. The operative diagnosis must match the admitted or presenting condition — Z89.51x (acquired absence) applies to follow-up encounters, not the surgical encounter itself.

Sources & references

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

Mira Scribe

Mira's AI scribe captures the immediate fitting technique, cast application details, level of bone transection, and laterality directly from surgeon dictation. It flags operative notes that describe a standard BKA closure without cast application — preventing the most common audit-driven downcode from 27881 to 27880 — and prompts for the underlying diagnosis code tied to the amputation indication.

See how Mira captures CPT 27881 documentation