Open tenotomy of multiple hamstring tendons, knee to hip, one leg — surgical division of two or more of the biceps femoris, semitendinosus, or semimembranosus tendons via open incision.

Verified May 8, 2026 · 6 sources ↓

Medicare: $551.78
Work RVU: 7.3
Global, days: 90
Region: Knee

Drawn from CMSAbosAAPCFindacodeFastrvu

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Specify which tendons were divided by name (biceps femoris, semitendinosus, semimembranosus) — 'multiple hamstrings' alone is insufficient.
Confirm laterality (left or right leg) explicitly in both the operative note and the procedure line.
Document the open approach and incision location; notes that reference only 'standard tenotomy' without describing exposure are audit flags.
Record the clinical indication (e.g., spastic contracture, cerebral palsy, fixed flexion deformity) with supporting ICD-10 diagnosis linking to medical necessity.
Include intraoperative findings — degree of contracture, tendon condition, and any intraoperative range-of-motion measurement — to support complexity.
For modifier 22, document the specific factors that increased difficulty (e.g., dense adhesions, prior surgery, neurovascular proximity) with time notation.

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 51 Multiple procedures 59 Distinct service 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27391 describes an open tenotomy in which the surgeon divides multiple hamstring tendons (from the knee-to-hip span) on a single leg. The hamstring group — biceps femoris, semitendinosus, and semimembranosus — is accessed through an open incision, and two or more tendons are cut to release contracture, correct deformity, or address pathological tightness. This distinguishes 27391 from 27390 (single tendon, one leg) and 27392 (multiple tendons, bilateral). The open approach also separates this family from the percutaneous tenotomy codes 27306 and 27307.

The 90-day global period governs all routine post-op care following this procedure. Any E/M visit during that window for a new or unrelated problem requires modifier 24. A return to the OR for a complication related to the original tenotomy uses modifier 78; an unrelated OR procedure in the global window uses modifier 79.

This code sits in the Repair, Revision, and/or Reconstruction section of the Femur (Thigh Region) and Knee Joint CPT subsection. It is billed almost exclusively by orthopedic surgery. When the identical procedure is performed on both legs at the same session, use 27392 — not 27391 with modifier 50.

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 (7.3) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (16.52) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	7.3
Practice expense RVU	7.7
Malpractice RVU	1.52
Total RVU	16.52
Medicare national rate	$551.78
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	$551.78
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI A2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 27391 get rejected.

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

Upcoding from 27390 (single tendon): payer audits the operative note and downcodes when only one tendon division is documented.
Bilateral procedure billed as 27391 with modifier 50 instead of the correct bilateral code 27392.
Missing or vague laterality on the claim line — payer rejects when LT or RT modifier is absent and the operative note doesn't resolve it.
Medical necessity not established: no documented diagnosis (e.g., contracture severity, functional limitation) supporting elective open tenotomy over percutaneous alternatives.
Global period conflict: post-op E/M visits billed without modifier 24 when unrelated to the tenotomy are bundled and denied.

Frequently asked questions

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

01When should I use 27391 versus 27390?

Use 27390 when only one hamstring tendon is divided open on one leg. Use 27391 when two or more tendons are divided open on the same leg in the same session. The operative note must name each tendon divided — if it doesn't, a payer or auditor will downcode to 27390.

02Can I bill 27391 with modifier 50 for a bilateral case?

No. When multiple hamstring tendons are released open on both legs at the same session, use 27392 — the dedicated bilateral code. CPT 27391 with modifier 50 is incorrect and will draw NCCI scrutiny.

03Is modifier 51 ever appropriate with 27391?

Yes, if 27391 is the secondary procedure in a same-session multi-procedure case. Append modifier 51 to the lower-value code per standard multiple-procedure reduction rules. Confirm the primary procedure is listed first on the claim.

04What ICD-10 codes typically support medical necessity for 27391?

Common supporting diagnoses include hamstring contracture (M62.45x), spastic diplegia or quadriplegia with lower-extremity contracture, and fixed knee flexion deformity. The diagnosis must document functional impairment severity, not just anatomical finding, to withstand payer review.

05How does the 90-day global period affect billing for follow-up care?

All routine post-op visits, wound checks, and stitch removals are bundled through day 90. Bill modifier 24 on any E/M during that window for a problem unrelated to the tenotomy. A return to the OR for a complication directly related to the original procedure uses modifier 78; an unrelated OR procedure in the global window uses modifier 79.

06Is open tenotomy (27391) ever confused with percutaneous tenotomy codes?

Yes. CPT 27307 covers percutaneous tenotomy of multiple adductor or hamstring tendons and is a lower-complexity, lower-RVU code. If the operative note describes a percutaneous technique, 27307 is correct. Use 27391 only when the record documents an open incision with direct visualization of the tendons.

Sources & references

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

Mira AI Scribe

Mira's AI scribe captures tendon-level detail from dictation — logging which of the three hamstring tendons were divided, the open approach, laterality, and intraoperative ROM findings. This prevents the most common audit failure on 27391: an operative note that says 'multiple tendons' without naming them, which triggers downcoding to 27390 on review.

See how Mira captures CPT 27391 documentation