Open surgical treatment of knee dislocation, including internal fixation when indicated, with primary repair of ligaments and augmentation or reconstruction as needed.

Verified May 8, 2026 · 7 sources ↓

Medicare: $1,067.49
Total RVUs: 31.96
Global, days: 90
Region: Knee

Drawn from CMSAAPCFindacodeNIHAoassn

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Confirm true knee dislocation diagnosis in the operative and clinical notes, not isolated ligament tear
Name each ligamentous structure repaired, reconstructed, or augmented with surgical technique described
Document whether internal fixation was used, specifying device type and placement
Record pre- and intraoperative neurovascular assessment, including pulse checks and any vascular surgery involvement
Specify surgical approach by name (e.g., medial, lateral, combined); do not use generic 'standard approach'
Include fluoroscopy or imaging findings if used intraoperatively to confirm reduction and fixation

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 59 Distinct service 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 7 cited references ↓

CPT 27558 covers open treatment of a knee dislocation — a high-energy, often limb-threatening injury — including internal fixation when performed, primary ligamentous repair, and augmentation or reconstruction of the supporting structures. This is a complex procedure addressing the multiligament disruption that defines true knee dislocations, distinct from simple subluxations or isolated ligament tears.

The 90-day global period means all routine post-op care, wound checks, and dressing changes through day 90 are included in the base payment. Separately identifiable services unrelated to the dislocation repair during that window require modifier 24 (E/M) or modifier 79 (unrelated procedure). Casting, splinting, or strapping applied at the time of surgery is bundled — do not bill those separately per NCCI policy.

Because knee dislocation frequently involves vascular injury, the operative note must document neurovascular assessment, the specific ligamentous structures repaired or reconstructed, fixation method, and the approach used. Audit teams flag operative reports that describe multiligament reconstruction without a clear dislocation diagnosis or that conflate 27558 with isolated ligament reconstruction codes (e.g., 27427–27429).

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	17.93
Practice expense RVU	10.2
Malpractice RVU	3.83
Total RVU	31.96
Medicare national rate	$1,067.49
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	$1,067.49
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 27558 get rejected.

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

Diagnosis code does not support true knee dislocation — isolated ligament tear codes (e.g., S83.x) used instead of dislocation-specific ICD-10
Unbundling of casting or splinting codes billed separately when application is included in 27558 per NCCI policy
Conflation with isolated ligament reconstruction codes (27427, 27428, 27429) without clear dislocation documentation, triggering NCCI or medical necessity edits
Missing or inadequate neurovascular assessment documentation, which payers use to question medical necessity of open approach
Post-op E/M services billed without modifier 24 during the 90-day global period, resulting in automatic denial

Frequently asked questions

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

01Can 27558 be billed with isolated ligament reconstruction codes like 27427 or 27428 on the same day?

Generally no. AAPC forum guidance and NCCI bundling principles indicate these codes hit edits when billed together. 27558 already includes primary ligamentous repair and augmentation — stacking isolated reconstruction codes is considered unbundling unless a clearly distinct, separately documented procedure was performed at a different anatomic site.

02Is casting or splinting separately billable when applied at the end of the procedure?

No. Per NCCI Chapter 4, CPT codes for open treatment of dislocations include the initial casting, splinting, or strapping. Do not bill casting or splinting codes alongside 27558.

03What modifier is needed to bill E/M services during the 90-day global period?

Use modifier 24 for unrelated E/M visits during the global period, and modifier 25 for a significant, separately identifiable E/M on the day of the procedure itself. Without these, the claims will auto-deny.

04Can a co-surgeon or assistant surgeon bill alongside 27558?

Yes. The code allows co-surgeon billing (modifier 62) and assistant surgeon billing (modifier 80 or AS for a PA/NP). Given the complexity of multiligament knee dislocation repair, co-surgeon arrangements are common and defensible when both surgeons' distinct roles are documented.

05If an unrelated procedure is needed during the global period — say, treatment of a separate fracture — what modifier applies?

Use modifier 79 for an unrelated procedure performed during the 90-day global period. Modifier 78 is only for unplanned returns to the OR for a complication related to the original knee dislocation repair.

06What ICD-10 codes support 27558?

True knee dislocation diagnosis codes — such as S83.10x through S83.19x (dislocation of knee, unspecified/specified direction) — are required. Using a sprain or ligament tear code alone will not support 27558 and will likely trigger a medical necessity denial.

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 dislocation mechanism, specific ligaments repaired or reconstructed, fixation devices used, surgical approach by name, and pre- and post-reduction neurovascular status directly from dictation. This prevents the most common audit flag for 27558 — an operative note that describes multiligament work without unambiguously documenting a true knee dislocation and its open treatment.

See how Mira captures CPT 27558 documentation