Surgical · Knee

Femoral osteotomy at the shaft or supracondylar region, performed with internal or external fixation to correct angular deformity or malalignment.

Verified May 8, 2026 · 6 sources ↓

Medicare: $928.55
Total RVUs: 27.8
Global, days: 90
Region: Knee

Drawn from CMSAbosFindacodeMdclarity

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Specify anatomic site: femoral shaft vs. supracondylar region
Document type of fixation used (plate, screws, external fixator) and confirm it was placed intraoperatively
Record the deformity type (varus, valgus, rotational) and the clinical indication driving the osteotomy
Include pre- and post-correction alignment measurements or fluoroscopic confirmation in the operative note
Note laterality (left vs. right femur) for modifier LT/RT assignment
If staged, document the surgical plan established before the index procedure to support modifier 58

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 58 Staged or related 59 Distinct service 76 Repeat, same physician 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side 80 Assistant surgeon 62 Co-surgeons

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27450 covers a femoral osteotomy — a deliberate surgical cut through the femur at the shaft or supracondylar level — performed with fixation hardware (plates, screws, or external fixation). The purpose is to realign the femur and correct deformity such as varus, valgus, or rotational malalignment. The companion code 27448 covers the same osteotomy without fixation; 27450 requires that fixation be placed and documented.

This is a 90-day global procedure. All routine post-op care, dressing changes, and standard follow-up visits through day 90 are bundled. Unrelated E/M services in that window require modifier 24; a separately identifiable same-day E/M needs modifier 25. A planned staged procedure in the global period — such as hardware removal or contralateral osteotomy — requires modifier 58. An unplanned return to the OR for a related complication uses modifier 78; an unrelated procedure in the global period uses modifier 79.

The procedure can be performed at the femoral shaft or supracondylar region; both sites are covered under 27450 as long as fixation is used. Document the specific anatomic site, the type and placement of fixation, the degree of deformity corrected, and the final alignment achieved. Audit reviewers will flag operative notes that omit fixation details or fail to distinguish 27450 from 27448.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	14.24
Practice expense RVU	10.63
Malpractice RVU	2.93
Total RVU	27.8
Medicare national rate	$928.55
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	$928.55
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI J8) Ambulatory surgical center (freestanding)	$4,682.29

Common denial reasons

The recurring reasons claims for CPT 27450 get rejected.

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

Fixation not documented in the operative note — payer downcodes to 27448 (osteotomy without fixation)
Missing or unsupported ICD-10 diagnosis code that does not establish a correctable deformity or malalignment
Laterality modifier (LT or RT) absent, triggering edit or return-to-provider request
Unbundling of included services (e.g., separately billing fluoroscopy or casting) without NCCI override
Post-op E/M billed in the 90-day global without modifier 24, resulting in automatic denial

Frequently asked questions

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

01What is the difference between CPT 27448 and CPT 27450?

27448 is a femoral osteotomy performed without fixation. 27450 is the same procedure with fixation placed. If you place a plate, screws, or external fixator, bill 27450. If the note doesn't document fixation, payers will downcode to 27448.

02Can I bill 27450 for both a shaft osteotomy and a supracondylar osteotomy performed at the same session?

No. 27450 covers both anatomic sites within a single code descriptor. Billing it twice for two levels on the same femur in the same session is incorrect unbundling. If additional work was substantially greater than typical, modifier 22 with supporting documentation is the appropriate path.

03What modifiers apply when 27450 is performed bilaterally?

Use modifier 50 for a bilateral procedure billed on a single line, or submit on separate lines with LT and RT. Confirm your payer's preference — some require 50, others require split lines. Medicare generally accepts modifier 50.

04How do I bill a planned contralateral femoral osteotomy that occurs during the 90-day global period?

Use modifier 58 to indicate a staged or related procedure performed during the postoperative period that was planned at the time of the original surgery. Document the staged plan in the original operative note or a pre-operative note to support the modifier.

05Does the 90-day global for 27450 include hardware removal if needed post-op?

If hardware removal is a planned staged procedure (documented as such), bill with modifier 58. If the patient returns unexpectedly for a related complication requiring a return to the OR, use modifier 78. Routine hardware removal that was never planned may still fall into the global unless payer policy or clinical circumstances support modifier 58 or 79.

06Can an assistant surgeon bill for 27450?

Yes. Assistant surgeon services are recognized for 27450. The assistant bills with modifier 80 (or AS for a physician assistant). Confirm that the operative note documents the assistant's participation and the medical necessity for assistance.

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 osteotomy site (shaft vs. supracondylar), fixation type and placement details, degree of deformity corrected, and final alignment from surgeon dictation. That prevents the single most common downcode on this code: a payer reclassifying 27450 to 27448 because the operative note didn't explicitly confirm fixation was applied.

See how Mira captures CPT 27450 documentation