Surgical lengthening of multiple hamstring tendons in a single leg, performed through open incision(s) from knee to hip region.

Verified May 8, 2026 · 7 sources ↓

Medicare: $619.25
Total RVUs: 18.54
Global, days: 90
Region: Knee

Drawn from CMSFindacodeAAPCGenhealthAbos

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Identify each specific hamstring tendon lengthened by name (e.g., semitendinosus, semimembranosus, biceps femoris long or short head)
State the lengthening technique used for each tendon (e.g., Z-plasty, fractional lengthening, slide technique)
Confirm the procedure was performed on one leg only — bilateral cases require 27395, not 27394 with modifier 50
Document the pre-operative diagnosis driving the procedure (e.g., spastic hamstring contracture, fixed knee flexion deformity) with supporting ICD-10
Include intraoperative findings, approach, and any neurovascular structures identified and protected
Note the total number of tendons lengthened — 'multiple' means two or more; single tendon defaults to 27393

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 25 Significant separate E/M 51 Multiple procedures 52 Reduced services 58 Staged or related 59 Distinct service 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 27394 covers open surgical lengthening of multiple hamstring tendons in one leg. It sits in a family of hamstring procedures: 27393 covers a single tendon, 27394 covers multiple tendons in one leg, and 27395 covers multiple tendons bilaterally. Selecting the wrong code in this family is a common audit trigger — the operative note must clearly identify each tendon lengthened and confirm the procedure was unilateral.

This procedure is performed most often in patients with spastic or contracted hamstrings causing fixed-knee flexion deformity — commonly seen in cerebral palsy, acquired neurologic conditions, or post-traumatic contracture. The surgeon elongates each tendon through fractional lengthening, Z-lengthening, or another open technique; document the specific technique used for each tendon. The 90-day global period applies, so post-op visits, dressing changes, and routine wound care through day 90 are bundled. Bill unrelated services in the global window with modifier 24 or 25.

Do not confuse 27394 with the tenotomy codes (27391 for multiple tendons, one leg). Tenotomy is a division or release; lengthening is a structural elongation that preserves tendon continuity. Payers and audit contractors distinguish these — operative dictation that describes a lengthening technique must match the lengthening code, not a release code.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	8.57
Practice expense RVU	8.15
Malpractice RVU	1.82
Total RVU	18.54
Medicare national rate	$619.25
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	$619.25
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI A2) Ambulatory surgical center (freestanding)	$3,695.53

Common denial reasons

The recurring reasons claims for CPT 27394 get rejected.

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

Wrong code in family selected — billing 27394 when only one tendon was lengthened (should be 27393)
Operative note describes tenotomy or release technique rather than a structural lengthening, creating a code-to-documentation mismatch
Missing medical necessity documentation — no functional deficit, contracture measurement, or failed conservative treatment noted in the record
Bilateral procedure billed as 27394 with modifier 50 instead of the correct bilateral code 27395
Global period violation — post-op E/M billed without modifier 24 when the visit was for a condition unrelated to the hamstring lengthening

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01What is the difference between CPT 27393 and 27394?

27393 is for lengthening a single hamstring tendon in one leg. 27394 is for multiple hamstring tendons in one leg. The operative note must name each tendon lengthened — vague documentation gets downgraded to 27393 on audit.

02When should I use 27395 instead of 27394?

Use 27395 when multiple hamstring tendons are lengthened in both legs during the same operative session. Do not bill 27394 with modifier 50 for a bilateral case — 27395 is the correct bilateral descriptor.

03How does the 90-day global period affect billing for 27394?

All routine post-op visits, wound checks, and dressing changes through day 90 are bundled. If you see the patient for a condition unrelated to the hamstring lengthening during that window, append modifier 24 to the E/M code and document the separate diagnosis clearly.

04Can 27394 be billed on the same day as a tenotomy code like 27391?

Billing both a hamstring lengthening and a hamstring tenotomy on the same leg same day will draw NCCI scrutiny. These describe different procedures on the same tendon group. If distinct tendons were addressed by each technique, use modifier 59 and document each tendon separately in the operative note.

05What ICD-10 codes most commonly support 27394?

Common supporting diagnoses include spastic hemiplegia or diplegia (G80.x series), hamstring contracture (M62.45x), and knee flexion contracture (M21.26x). The diagnosis must reflect a documented functional deficit to establish medical necessity.

06Is modifier 22 ever appropriate for 27394?

Yes, if the procedure involved significantly increased complexity — for example, prior scarring from previous hamstring surgery, severe spasticity requiring additional dissection, or revision in a previously operated field. Document the specific factors that increased operative time and difficulty; modifier 22 claims without that documentation are routinely denied.

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 name of each tendon lengthened, the specific technique used (Z-plasty, fractional lengthening, slide), laterality, and the functional indication from the surgeon's dictation. This prevents the most common denial pattern for 27394: an operative note that says 'hamstring lengthening performed' without specifying which tendons or how many — exactly what audit contractors flag when distinguishing 27393 from 27394.

See how Mira captures CPT 27394 documentation