Fracture care · Knee

27556

Open surgical reduction of a dislocated knee joint with internal fixation when needed, performed without primary ligament repair or ligamentous reconstruction.

Verified May 8, 2026 · 7 sources ↓

Medicare
$798.62
Total RVUs
23.91
Global, days
90
Region
Knee
Drawn from CMSFastrvuAbosAAPCFindacode

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

  • Operative note must state the mechanism and direction of dislocation (anterior, posterior, lateral, medial, rotatory).
  • Explicitly document that no primary ligamentous repair or augmentation/reconstruction was performed — absence of this statement invites upcoding scrutiny.
  • Record neurovascular status pre- and post-reduction, including ABI or vascular surgery consultation if performed.
  • Specify whether internal fixation was used; if so, document hardware type, size, and placement site.
  • Document staged reconstruction plan if ligament repair is deferred, to support medical necessity for the limited scope of 27556.
  • Include intraoperative fluoroscopy or imaging confirmation of reduction if obtained.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 27556 covers open treatment of a knee dislocation — including internal fixation when used — where the surgeon does not perform any primary ligamentous repair or augmentation/reconstruction at the same operative session. This distinguishes it from 27557 (with primary ligamentous repair) and 27558 (with repair plus augmentation/reconstruction). Choose the code that matches what was actually done to the ligaments; upcoding to 27557 or 27558 when only bony reduction and fixation were performed is an audit target.

Knee dislocations are high-energy injuries frequently involving multiligamentous disruption, vascular injury, and neurovascular compromise. When the operative plan addresses only the osseous dislocation — staged ligament reconstruction is deferred, or the ligaments were intact enough not to require repair — 27556 is the correct primary code. Internal fixation hardware (pins, screws) used to stabilize the reduction is included and not separately reportable.

The 90-day global period means all routine post-op care through day 90 is bundled. Unrelated E/M services in that window require modifier 24. If a complication requires a return to the OR for a related procedure (e.g., hardware adjustment), use modifier 78. An unrelated surgical problem addressed in the global period uses modifier 79.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU12.68
Practice expense RVU8.53
Malpractice RVU2.7
Total RVU23.91
Medicare national rate$798.62
Global period90 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

SettingMedicare rate (national)
Office (PFS non-facility)
Procedure performed in physician's office
$798.62
HOPD (APC 5114)
Hospital outpatient department
$7,413.38
ASC (PI G2)
Ambulatory surgical center (freestanding)
$3,695.53

Common denial reasons

The recurring reasons claims for CPT 27556 get rejected.

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

  • Code billed as 27557 or 27558 when operative note describes only bony reduction without documented ligament repair — or vice versa, 27556 billed when ligament repair was actually performed.
  • Missing documentation of ligamentous management (repair vs. deferred) causes payer to downcode or deny for insufficient operative detail.
  • Global period violations: E/M or follow-up visits billed within 90 days without modifier 24, triggering automatic denial.
  • Laterality not specified on the claim; payers requiring LT/RT modifier will reject without it.
  • Medical necessity denied when the operative report does not document neurovascular status or imaging confirming true dislocation versus subluxation.

Frequently asked questions

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

01What separates 27556 from 27557 and 27558?
27556 is used when the surgeon reduces the dislocation and stabilizes it without repairing the ligaments. 27557 adds primary ligamentous repair. 27558 adds both primary repair and augmentation or reconstruction. The distinction is what was done to the ligaments intraoperatively — not what is planned for a future stage.
02Can 27556 be billed with a ligament reconstruction code at the same session?
No. If ligament repair was performed at the same operative session, you must move to 27557 or 27558. Billing 27556 alongside an arthroscopic or open ligament reconstruction code for the same knee same-day will trigger NCCI bundling review.
03Is staged ligament reconstruction after 27556 billable separately?
Yes. If ligament reconstruction is performed as a planned separate procedure after the 90-day global period closes, it is billed independently. If it occurs within the global period for a related indication, use modifier 58 (staged or related procedure during the global).
04Does 27556 require a specific place of service?
This is an open surgical procedure and is performed in a hospital OR or ASC. The site of service affects payment — HOPD and ASC facility rates differ materially. The physician professional fee is also subject to site-of-service differential; see the Site of Service comparison on this page.
05Can modifier 22 be used with 27556?
Yes, but document the basis explicitly. A knee dislocation with multi-planar instability, vascular injury requiring repair, or morbid obesity significantly increasing operative complexity supports modifier 22. Attach an operative note that quantifies the additional time and complexity — payers routinely request records when 22 is appended.
06When is modifier 62 appropriate for this procedure?
Modifier 62 applies when two surgeons of different specialties (e.g., orthopedic and vascular) perform distinct, necessary portions of the same operative session simultaneously. A common scenario is concurrent vascular repair of a popliteal artery injury alongside the orthopedic reduction. Both surgeons bill 27556-62 and document their distinct roles.
07Does 27556 cover a dislocated knee prosthesis?
Coding forum consensus supports using 27556 for open reduction of a dislocated knee prosthesis when no ligament repair is performed, as the code language does not restrict it to native joints. However, confirm with your payer, as some commercial plans may require a different code for prosthetic dislocation scenarios.

Mira AI Scribe

Mira's AI scribe captures the specific direction of dislocation, intraoperative ligamentous findings (intact vs. disrupted), the decision not to perform primary repair or reconstruction, hardware used for fixation, and pre/post-reduction neurovascular status. That documentation directly prevents downcoding to closed treatment codes and shields against upcoding allegations when 27557 or 27558 were not warranted.

See how Mira captures CPT 27556 documentation

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