Surgical · Knee

Proximal tibial osteotomy with fibular excision or osteotomy to correct varus (bowleg) or valgus (knock-knee) deformity at the knee joint.

Verified May 8, 2026 · 8 sources ↓

Medicare: $880.11
Total RVUs: 26.35
Global, days: 90
Region: Knee

Drawn from CMSFastrvuMdclarityFindacode

Documentation requirements

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

Source · Editorial brief grounded in 8 cited references ↓

Specify the type of deformity corrected: genu varum (varus) or genu valgum (valgus), with preoperative alignment measurements.
Document whether fibular excision or osteotomy was performed — this distinguishes 27457 from 27455.
Include preoperative weight-bearing radiographs demonstrating the degree of angular deformity and compartment involvement.
Operative note must describe the osteotomy technique, fixation method (plate, staples, external fixator), and any bone grafting used.
Document the indication for osteotomy versus arthroplasty, especially in younger or high-activity patients where joint preservation is the goal.
Record intraoperative alignment verification (fluoroscopy or mechanical axis rod) confirming correction achieved.

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 LT Left side RT Right side 76 Repeat, same physician 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon 62 Co-surgeons AS PA/NP/CNS assistant

What this code covers

Source · Editorial summary grounded in 8 cited references ↓

CPT 27457 covers a proximal tibial osteotomy — with associated fibular excision or osteotomy as needed — performed to correct angular deformity of the knee. The procedure addresses genu varum (bowleg) or genu valgum (knock-knee), typically in patients with unicompartmental arthritis or malalignment that has failed conservative management. The surgeon cuts and repositions the proximal tibia to shift load-bearing forces away from the damaged compartment, restoring mechanical alignment.

This is a 90-day global procedure. All routine postoperative care through day 90 is bundled — including office visits, dressing changes, and hardware checks — unless a separately identifiable, unrelated service is rendered, which requires modifier 24 or 25. Staged or anticipated subsequent procedures within the global window use modifier 58; an unplanned return to the OR for a related complication uses modifier 78; an unrelated OR procedure in the global period uses modifier 79.

Note that 27457 represents the more complex version of proximal tibial osteotomy. Its sister code, 27455, covers the same anatomical site without fibular excision or osteotomy. Select the code that matches what was actually performed — operative notes must document whether fibular work was done. NCCI edits bundle 27447 (total knee arthroplasty) as a component of 27457; do not report both on the same date unless documentation clearly supports a distinct service with modifier 59.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	13.68
Practice expense RVU	9.76
Malpractice RVU	2.91
Total RVU	26.35
Medicare national rate	$880.11
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	$880.11
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI G2) Ambulatory surgical center (freestanding)	$3,695.53

Common denial reasons

The recurring reasons claims for CPT 27457 get rejected.

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

Incorrect code selection — billing 27457 when no fibular work was done (should be 27455).
Medical necessity not established — missing preoperative imaging, alignment measurements, or documentation of failed conservative care.
Unbundling 27447 (TKA) with 27457 on the same date without a modifier 59 and supporting distinct-service documentation.
Global period violations — billing routine follow-up E/M visits within the 90-day global without modifier 24.
Missing laterality modifier (LT or RT) when payer requires it for unilateral knee procedures.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01What is the difference between CPT 27455 and 27457?

Both describe proximal tibial osteotomy for knee realignment, but 27457 includes fibular excision or osteotomy — 27455 does not. Select the code that matches what was performed. Billing 27457 without documentation of fibular work is an audit risk.

02Can 27457 and 27447 be billed together on the same date?

Generally no — NCCI edits bundle 27447 as a component of 27457. If there is a genuinely distinct procedural service supported by documentation, modifier 59 may apply, but this scenario is clinically uncommon and will draw scrutiny.

03What global period applies to 27457, and what does it include?

27457 carries a 90-day global period. Routine post-op office visits, dressing changes, and hardware monitoring through day 90 are all bundled. Unrelated E/M services need modifier 24; a new or staged procedure needs modifier 58.

04Is modifier 50 appropriate when bilateral tibial osteotomies are performed?

Yes. If the surgeon performs the realignment on both knees in the same operative session, modifier 50 applies. Document bilateral deformity and the surgical rationale for simultaneous correction.

05What ICD-10 diagnoses typically support medical necessity for 27457?

Common supporting diagnoses include M17.11/M17.12 (primary osteoarthritis, knee, unicompartmental), M21.161/M21.162 (varus deformity of knee), and M21.061/M21.062 (valgus deformity). Payers expect deformity diagnosis codes paired with osteoarthritis or mechanical complication codes.

06Is 27457 typically performed in an ASC or HOPD setting?

Both are used. HOPD and ASC payment rates differ significantly — see the site-of-service comparison on this page. Younger, healthier patients without significant comorbidities are increasingly scheduled at ASCs where the procedure is on the approved list.

07If hardware removal is needed after the 90-day global, how is that billed?

Hardware removal after the global period closes is billed separately under the appropriate removal code (e.g., 20680 for deep implant). No modifier is needed once the global window has expired.

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 deformity type (varus vs. valgus), degree of angular correction achieved, whether fibular excision or osteotomy was performed, fixation construct used, and intraoperative alignment confirmation. This directly prevents downcoding to 27455 on audit and supports medical necessity when payers scrutinize joint-preservation cases in younger patients.

See how Mira captures CPT 27457 documentation