Single hamstring tendon lengthening procedure performed from the knee to hip region via open incision

Verified May 8, 2026 · 6 sources ↓

Medicare: $476.96
Work RVU: 6.43
Global, days: 90
Region: Knee

Drawn from CMSAAPCAbosCgsmedicareAAOS

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Identify the specific tendon lengthened by name (biceps femoris, semitendinosus, or semimembranosus) — 'hamstring tendon' alone is insufficient
Document the surgical technique used for lengthening (Z-plasty, step-cut, fractional/intramuscular) to support medical necessity and defend against down-coding
Record pre-operative functional deficit: measured knee extension lag or popliteal angle, gait analysis findings, or spasticity grading (e.g., Modified Ashworth Scale)
State the underlying diagnosis driving the contracture (cerebral palsy, post-stroke spasticity, post-traumatic contracture) with matching ICD-10 code
Specify laterality (left, right) in both the operative note and on the claim to support LT/RT modifiers
Confirm single-tendon scope in the operative note — if a second tendon was addressed intraoperatively, document it explicitly to justify upgrading to 27394

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 AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27393 covers open surgical lengthening of a single hamstring tendon — biceps femoris, semitendinosus, or semimembranosus — anywhere along the knee-to-hip corridor. The procedure addresses fixed flexion contractures, spasticity-driven shortening (commonly seen in cerebral palsy, stroke, or TBI patients), or post-traumatic tightness limiting functional range of motion. The surgeon incises and elongates the tendon using a Z-plasty, step-cut, or fractional lengthening technique, then closes and immobilizes the extremity.

When multiple hamstring tendons are lengthened on the same leg in the same session, step up to 27394. Bilateral single-session work on multiple tendons goes to 27395. Do not stack 27393 units to represent additional tendons — that's a misuse that NCCI edits will catch.

The 90-day global period means all routine follow-up, suture removal, cast checks, and wound management through day 90 are bundled. Return to the OR for a related complication within the global bills under modifier 78. A staged procedure planned at the time of the index surgery uses modifier 58 and resets the global clock.

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 (6.43) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (14.28) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	6.43
Practice expense RVU	6.58
Malpractice RVU	1.27
Total RVU	14.28
Medicare national rate	$476.96
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	$476.96
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 27393 get rejected.

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

Tendon not identified by name in operative note — payer or auditor cannot confirm single-tendon scope, triggering a request for records or outright denial
Wrong code selected when multiple tendons were lengthened on one leg (should be 27394) or bilateral multiple tendons (27395) — units stacked on 27393 instead
Missing or weak medical necessity documentation — no objective contracture measurement, functional limitation, or failed conservative treatment on record
Laterality modifier absent (LT or RT) causing claim rejection or edit on payers that require anatomical specificity
Global period billing conflict — post-op visits billed without modifier 24 or unrelated surgery billed without modifier 79 during the 90-day window

Frequently asked questions

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

01When do I use 27393 versus 27394 or 27395?

27393 is strictly one tendon, one leg. Move to 27394 when two or more hamstring tendons are lengthened on the same leg in the same session. Use 27395 when multiple tendons are lengthened bilaterally. Never stack 27393 units to represent additional tendons — NCCI edits will deny the extra units.

02Can 27393 be billed with hamstring tenotomy codes like 27390 or 27391 on the same day?

Generally no — lengthening and open tenotomy of the same tendon on the same day are mutually exclusive. If distinct tendons were addressed by different procedures, modifier 59 (or XS for a separate structure) may be appropriate, but you need clear operative documentation identifying each tendon and the distinct technique applied to each.

03What modifier applies when this is done bilaterally for a single tendon on each side?

Bill 27393 with modifier 50 for a bilateral single-tendon procedure (one tendon per leg, same session). Use LT and RT on separate line items if your payer requires that format instead of modifier 50 on a single line.

04Does the 90-day global period affect how I bill post-op physical therapy or casting changes?

Casting changes and routine wound checks by the operating surgeon are bundled into the 90-day global and not separately billable. Physical therapy services billed by a separate therapist or PT practice are not subject to the surgical global and bill independently.

05Is modifier 22 supportable for this procedure, and what documentation is required?

Modifier 22 applies when the work is substantially greater than typical — for example, severe fibrosis from prior surgery, extreme spasticity requiring unusual technique, or significantly prolonged operative time. Document the specific complicating factor in the operative note and include a cover letter quantifying the added work when submitting.

06What ICD-10 codes are typically paired with 27393?

Common diagnoses include M67.851–M67.852 (plica syndrome is not applicable here — use contracture codes), M24.561–M24.562 for joint contracture of the knee, G80-series codes for cerebral palsy with spasticity, and M62.451–M62.452 for contracture of muscle of the thigh. Match the code to the documented underlying etiology.

Sources & references

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

Mira Scribe

Mira's AI scribe captures the tendon name, lengthening technique, pre-op contracture measurements, and laterality directly from the surgeon's dictation, then flags the note if any of those elements are missing before the claim is generated. That prevents the most common audit trigger — an operative note that says 'hamstring tendon lengthened' without specifying which one or how.

See how Mira captures CPT 27393 documentation