Surgical cutting and realignment of both the tibia and fibula to correct lower leg deformity, malalignment, or leg-length discrepancy.

Verified May 8, 2026 · 6 sources ↓

Medicare: $1,051.13
Total RVUs: 31.47
Global, days: 90
Region: Foot & ankle

Drawn from CMSEmednyBeonbrandAAPCGenhealth

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Specify the indication by name: malunion, tibial torsion, genu varum, genu valgum, or leg-length discrepancy — not just 'deformity'.
Confirm both tibia and fibula were cut; if only one bone was osteotomized, 27709 does not apply.
Document the type of fixation used: plate and screws, intramedullary rod, external fixator, or other hardware.
Include pre-op alignment measurements (mechanical axis, tibial torsion angle, or limb-length discrepancy in centimeters) and post-op confirmation imaging.
Record the surgical approach and incision location(s) for each bone separately in the operative note.
For bilateral cases, document each limb independently with separate clinical justification.

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

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27709 describes an osteotomy performed on both the tibia and fibula in the same operative session. The surgeon cuts one or both bones, repositions them to correct the mechanical axis or leg length, and stabilizes the construct with internal fixation — plates, screws, or an intramedullary rod. Indications include post-traumatic malunion, angular deformity (genu varum or genu valgum), rotational malalignment such as tibial torsion, and leg-length inequality. When the fibula alone requires osteotomy, use 27707. When only the tibia is cut, use 27705. 27709 is the correct code only when both bones are addressed.

The 90-day global period covers all routine post-op care through day 90 — wound checks, cast changes, and alignment confirmations. Unrelated E/M services in that window require modifier 24. A staged or planned return to address the same condition — hardware exchange, bone grafting for delayed union — uses modifier 58. An unplanned return to the OR for a complication related to the osteotomy uses modifier 78.

If this osteotomy is performed bilaterally in the same session, bill with modifier 50. For unilateral cases, append LT or RT per payer requirement. NCCI bundles 29897 (ankle arthroscopy) with 27709 — billing both together will trigger a denial unless a distinct anatomic and clinical basis is documented 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	17.04
Practice expense RVU	11.06
Malpractice RVU	3.37
Total RVU	31.47
Medicare national rate	$1,051.13
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	$1,051.13
HOPD (APC 5115) Hospital outpatient department	$13,116.76
ASC (PI J8) Ambulatory surgical center (freestanding)	$8,873.30

Common denial reasons

The recurring reasons claims for CPT 27709 get rejected.

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

Wrong code selection — 27705 (tibia only) or 27707 (fibula only) billed when both bones were addressed, or vice versa.
Missing documentation that both the tibia and fibula were osteotomized; operative note describes only one bone.
NCCI bundle denial when 29897 is billed same-session without modifier 59 and supporting documentation of a distinct procedure.
Global period denial for post-op visits billed without modifier 24, when the visit is unrelated but not documented as such.
Bilateral procedure billed without modifier 50 or individual LT/RT modifiers, per payer requirements.
Insufficient medical necessity documentation — no pre-op imaging measurements or failed conservative treatment history on record.

Frequently asked questions

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

01When does the osteotomy require both 27709 instead of 27705 or 27707?

Use 27709 only when you cut both the tibia and the fibula in the same session. If only the tibia is osteotomized, bill 27705. Fibula alone is 27707. Auditors will downcode 27709 if the operative note doesn't document osteotomy of both bones.

02Can 27709 be billed with proximal tibial osteotomy codes like 27455 or 27457?

27455 and 27457 describe proximal tibial osteotomies specifically for genu varus/valgus correction at the proximal metaphysis. 27709 covers osteotomy of the tibial and fibular shafts. Billing both for the same bone segment in the same session is unlikely to survive audit — document distinct anatomic levels if both are genuinely performed.

03What modifier applies if the patient returns to the OR for hardware failure within the 90-day global?

If the return is directly related to the original osteotomy — hardware failure, loss of fixation, wound complication — use modifier 78. If you're addressing a completely unrelated condition in the same operative session, use modifier 79. Do not invert these.

04Is an iliac crest bone graft separately billable when performed with 27709?

Autograft harvesting from the iliac crest is generally separately reportable. Check NCCI edits and your payer's bundling policy. Document the graft harvest site, technique, and volume distinctly in the operative note to support a separate line item.

05How should bilateral tibial and fibular osteotomies be billed?

Bill 27709 once with modifier 50 for bilateral same-session procedures, or as two line items with LT and RT per your payer's preference. Medicare typically accepts the modifier 50 approach with a single line; many commercial payers want two lines. Verify before submission.

06Does the 90-day global include intramedullary lengthening device management?

27709 is a standard osteotomy code without an implanted lengthening device. If an externally controlled intramedullary lengthening device is inserted, 27713 is the applicable code, which includes imaging, alignment assessments, and device management in its descriptor. Don't bill 27709 for that scenario.

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 named indication (e.g., tibial torsion, post-traumatic malunion, genu varum), confirms osteotomy of both tibia and fibula, records fixation type and hardware, and pulls pre-op alignment measurements from dictation into the structured note. That prevents the most common audit flag on 27709: an operative note that describes work on only one bone, forcing a downcode to 27705 or 27707.

See how Mira captures CPT 27709 documentation