Surgical revision or complete removal of the patella (kneecap), performed to address a chronically dislocating or previously failed patella procedure.

Verified May 8, 2026 · 7 sources ↓

Medicare: $704.09
Total RVUs: 21.08
Global, days: 90
Region: Knee

Drawn from CMSCgsmedicareAAPCMdclarityPayerprice

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Operative report must identify whether the procedure was a revision of a prior patellar surgery or a complete patellectomy — 'revision/removal' is not sufficient specificity.
Document the specific indication: chronic dislocation, failed prior stabilization, painful hardware, or other pathology driving the decision to revise or remove.
Record prior surgical history and what prior procedure is being revised, including approximate date, to support medical necessity for re-operation.
Describe approach and intraoperative findings in detail — audit teams flag notes that reference only 'standard approach' without naming structures addressed.
Include pre-op imaging (X-ray or MRI) in the chart supporting the diagnosis and the surgical plan.
If modifier 22 is appended, document specific factors increasing complexity: excessive scar tissue, significant anatomic distortion, prolonged operative time with explanation.

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 50 Bilateral procedure 51 Multiple procedures 58 Staged or related 59 Distinct service 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side XS Separate structure

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 27424 covers surgical intervention on the patella that goes beyond a simple repair — either revising a prior patellar procedure or performing a patellectomy (total removal). The most common indication is a patella that persistently dislocates despite prior stabilization, or a failed prior patellar fixation or realignment. The surgeon addresses the underlying mechanical or structural problem, which may involve bony work, soft-tissue release, or excision of the entire patella depending on intraoperative findings.

This is a 090-day global procedure. All routine post-op visits, dressing changes, and stitch removals through day 90 are bundled. Any E/M service for an unrelated condition during the global window requires modifier 24; a separately identifiable E/M on the day of surgery requires modifier 25. A staged or planned return to the OR for a related procedure uses modifier 58; an unplanned return for a related problem uses modifier 78; an unrelated procedure in the global period uses modifier 79.

Site of service matters significantly here. HOPD and ASC payments differ substantially — check the Site of Service comparison table on this page. Bilateral patella surgery is rare but possible; report with modifier 50 on a single claim line for professional billing. ASC facilities report two lines with modifiers LT and RT per NCCI guidance.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.98
Practice expense RVU	8.97
Malpractice RVU	2.13
Total RVU	21.08
Medicare national rate	$704.09
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	$704.09
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI A2) Ambulatory surgical center (freestanding)	$3,695.53

Common denial reasons

The recurring reasons claims for CPT 27424 get rejected.

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

Medical necessity denied when documentation does not demonstrate failure of conservative treatment or a prior surgical attempt before revision.
Bundling denial when an arthroscopic procedure (e.g., diagnostic scope) is billed same-day without a modifier establishing it as a distinct, separate service.
Global period violation — E/M or minor procedure billed during the 90-day post-op window without modifier 24 or 79 to indicate it is unrelated to the index surgery.
Incorrect modifier use: modifier 78 applied to an unrelated return-to-OR procedure (should be 79), or modifier 79 applied to a planned staged procedure (should be 58).
Claim rejected for missing laterality modifier when payer requires LT or RT on all knee procedure claims.

Frequently asked questions

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

01What is the global period for CPT 27424?

90 days. The surgery date plus all routine follow-up care through day 90 is bundled. Use modifier 24 for unrelated E/M visits and modifier 79 for unrelated procedures performed in that window.

02Can 27424 be billed with an arthroscopy code on the same day?

Only if the arthroscopic procedure is truly distinct and separately documented. You'll need modifier 59 or XS to unbundle, and the chart must support that the scope was not a component of the open revision. NCCI PTP edits apply — check the CGS NCCI lookup tool before submitting.

03When does modifier 22 apply to 27424?

When the procedure required substantially more work than typical — dense scar tissue from multiple prior surgeries, severe anatomic distortion, or significantly prolonged operative time. Document the specific factors in the operative note; payers will request the record before paying the upcharge.

04How do you bill 27424 for a bilateral procedure?

Professional claims: report on one line with modifier 50. ASC facility claims: report on two separate lines, one with modifier LT and one with RT, each with one unit of service — per NCCI Chapter 4 guidance for ASC bilateral reporting.

05What modifier applies if the patient returns to the OR during the 90-day global for a related complication?

Modifier 78 — unplanned return to the OR for a procedure related to the original surgery. If the return procedure is unrelated to the original surgery, use modifier 79 instead. Do not invert these.

06What ICD-10 diagnosis codes are typically paired with 27424?

Common pairings include M22.0x (recurrent dislocation of patella), M22.2x (patellofemoral disorders), T84.xx (complications of internal joint prosthesis or hardware), and M22.8x (other disorders of patella). Confirm your payer's covered diagnosis list — some require documented failed conservative or surgical treatment.

07Is 27424 subject to SNF consolidated billing?

Review your payer's SNF CB exclusion list. CMS periodically updates which surgical codes are excluded from SNF PPS bundling. If the patient is in a covered Part A SNF stay, confirm 27424's exclusion status before billing separately to Medicare.

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 specific surgical intent from dictation — revision versus complete patellectomy, the named prior procedure being revised, approach, intraoperative findings, and pathology encountered (e.g., scar tissue burden, hardware failure, extent of dislocation). This prevents the most common audit flag for 27424: an operative note that documents 'revision of kneecap' without identifying what was revised, why, or what was done — the combination that triggers medical necessity denial and RAC scrutiny.

See how Mira captures CPT 27424 documentation