Open treatment of knee dislocation with internal fixation and primary ligamentous repair, without augmentation or reconstruction.

Verified May 8, 2026 · 5 sources ↓

Medicare: $943.24
Total RVUs: 28.24
Global, days: 90
Region: Knee

Drawn from CMSAbosAAPCAAOS

Documentation requirements

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

Source · Editorial brief grounded in 5 cited references ↓

Confirm open approach — closed reduction maps to a different code family entirely
Identify each ligament repaired by name (e.g., ACL, PCL, MCL, LCL, PLC) — 'ligamentous structures were repaired' is insufficient
State whether augmentation or reconstruction was performed; its absence distinguishes 27557 from 27558
Document neurovascular assessment pre- and post-reduction, including popliteal artery status — knee dislocations carry high vascular injury risk and auditors expect it
Record internal fixation hardware used, if applicable, including type and placement
Specify the dislocation direction (anterior, posterior, medial, lateral, rotatory) and mechanism of injury for ICD-10 linkage

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 57 Decision for surgery 58 Staged or related 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 27557 covers open reduction of a dislocated knee joint with internal fixation, performed alongside direct repair of the primary disrupted ligament(s). It sits in the middle of a three-code family: 27556 handles open treatment without any ligament repair; 27557 adds primary ligamentous repair; 27558 goes further with augmentation or reconstruction of the repaired ligament. Choosing the wrong sibling code is the most common billing error on these cases — the operative note must explicitly state that primary repair was performed and name the ligament(s) repaired.

CMS designates 27557 as an inpatient-only procedure (status indicator C under OPPS). It cannot be billed to Medicare in a hospital outpatient or ASC setting — doing so results in automatic non-payment. The 90-day global period means all routine post-op care through day 90 is bundled. Separate E/M visits during that window require modifier 24 for unrelated services or modifier 57 if the decision for surgery was made the day of or day before a subsequent major procedure. Return trips to the OR for related complications bill with modifier 78; unrelated procedures in the global window use 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 RVU	15.5
Practice expense RVU	9.43
Malpractice RVU	3.31
Total RVU	28.24
Medicare national rate	$943.24
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	$943.24
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 27557 get rejected.

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

OPPS status indicator C — billed in outpatient hospital or ASC setting, which CMS prohibits for this code
Code mismatch with 27556 or 27558 — operative note does not clearly support ligamentous repair (27557) versus no repair (27556) or augmented repair (27558)
ICD-10 diagnosis does not support traumatic knee dislocation — using a subluxation or instability code instead of the appropriate dislocation code
Unbundling of ligament repair — billing a separate ligament repair CPT alongside 27557 when the repair is already captured in the code descriptor
Missing medical necessity documentation for inpatient admission — payers may question level of care if the record lacks documentation of vascular status, neurovascular compromise, or surgical complexity

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What separates 27557 from 27556 and 27558?

27556 = open treatment with no ligament work. 27557 = open treatment plus primary direct ligament repair. 27558 = open treatment plus primary repair AND augmentation or reconstruction. The operative note must make this distinction explicit — the code selection follows the ligament work, not the surgeon's impression.

02Can 27557 be performed in an ASC or hospital outpatient setting?

No. CMS assigns status indicator C to 27557 under OPPS, classifying it as inpatient-only. Medicare will not pay this code billed from an outpatient hospital or ASC. The procedure must be performed with an inpatient admission.

03What ICD-10 codes support 27557?

Traumatic knee dislocation codes from the S83 category are the appropriate diagnostic linkage — for example, S83.10x (unspecified dislocation of knee) or the more specific directional codes. Patellar dislocation codes do not map to this procedure.

04If the surgeon also repairs a popliteal artery injury at the same session, how is that billed?

Vascular repair is not bundled into 27557. The vascular procedure is separately reportable with the appropriate vascular CPT code. Append modifier 51 to the secondary procedure if billing under the same surgeon. Confirm NCCI edits are not active between the specific codes before submitting.

05How does the 90-day global period affect post-op care billing for 27557?

All routine follow-up — wound checks, cast changes, physical therapy referrals, and standard post-op visits — is bundled through day 90. Bill modifier 24 on an E/M for unrelated problems. If the patient requires a return to OR for a related complication, use modifier 78. An unrelated surgical procedure in the global window gets modifier 79.

06When is modifier 22 appropriate for 27557?

Modifier 22 applies when the complexity substantially exceeds the typical case — for example, a multiligament dislocation with concurrent vascular repair, severe soft tissue injury requiring extensive reconstruction, or a morbidly obese patient with significantly increased operative time. The operative note must quantify the additional work and time; a blanket statement that the case was 'complex' will not support the modifier.

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 surgical approach, names of each ligament repaired, explicit confirmation that no augmentation or reconstruction was performed, internal fixation details, and pre/post-reduction neurovascular findings from dictation. This prevents the most common audit trigger — an operative note that documents a repair was done without specifying which ligament — and locks in the distinction between 27557 and its siblings 27556 and 27558.

See how Mira captures CPT 27557 documentation