Reconstruction of a dislocating patella using extensor mechanism realignment, muscle advancement, or soft-tissue release techniques (e.g., Campbell or Goldthwaite-type procedures).

Verified May 8, 2026 · 8 sources ↓

Medicare: $698.75
Total RVUs: 20.92
Global, days: 90
Region: Knee

Drawn from CMSAAPCBedrockbillingNimblercmAAOS

Documentation requirements

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

Source · Editorial brief grounded in 8 cited references ↓

Name the specific technique performed (e.g., Campbell, Goldthwaite, VMO advancement, medial reefing) — 'standard realignment' is an audit flag
Confirm patellar instability diagnosis with lateralization or dislocation documented on imaging or clinical exam findings
Document that the primary work involved tendons and/or muscles, not isolated ligamentous reconstruction, to support 27422 over 27427
Describe each component of the extensor mechanism addressed (e.g., lateral release, medial reefing, tibial tubercle transfer) to substantiate the reconstruction
If billing a same-day arthroscopic lateral release (29873) as a distinct service, document the separate clinical necessity and apply appropriate NCCI modifier
Operative note must specify laterality (left vs. right) to support LT/RT modifier on the claim

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 52 Reduced services 58 Staged or related 59 Distinct service 62 Co-surgeons 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 8 cited references ↓

CPT 27422 covers open reconstruction of patellar instability through realignment of the extensor mechanism — including procedures that advance or release the vastus medialis oblique (VMO), reefing of the medial retinaculum, or distal realignment techniques. It captures the tendon and muscle work involved in correcting a dislocating patella; it is not the right code when the primary intervention is isolated ligament reconstruction. The AMA currently recommends 27422 for PTFL (patellofemoral ligament) reconstruction, though note that AHA Coding Clinic has taken a different position (recommending 27566), so payer-specific guidance matters here.

The 90-day global period means all routine follow-up through day 90 is bundled — no separate E/M billing unless modifier 24 is appended for a clearly unrelated condition. NCCI bundles arthroscopic lateral release (29873) into 27422 as a component procedure; billing both without a modifier override will result in denial of 29873. If a distinctly separate procedure is performed at the same encounter and the NCCI edit allows an override, modifier 59 or an X-modifier is required with supporting documentation.

Do not confuse 27422 with 27427, which covers extra-articular ligament reconstruction of the knee. The distinction turns on whether the primary work involves tendons/muscles (27422) or discrete extra-articular ligamentous structures (27427). Mislabeling the procedure in the operative note is the most common root cause of miscoding between these two.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.95
Practice expense RVU	8.89
Malpractice RVU	2.08
Total RVU	20.92
Medicare national rate	$698.75
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	$698.75
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 27422 get rejected.

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

NCCI bundle denial when 29873 (arthroscopic lateral release) is billed same-day without a modifier override
Code mismatch between 27422 and diagnosis — payer edits flag claims without a patellar instability or dislocation ICD-10 code
Miscoding as 27427 (extra-articular ligament reconstruction) when the procedure involved muscle/tendon advancement, leading to downcoding or denial on review
Missing laterality modifier (LT or RT) triggering claim suspension or rejection at the clearinghouse level
Post-op E/M billed within the 90-day global without modifier 24, resulting in bundling denial

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01What is the difference between 27422 and 27427 for MPFL reconstruction?

27422 covers reconstruction involving tendons and muscles (extensor realignment). 27427 covers extra-articular ligament reconstruction. For MPFL/PTFL work, the AMA currently recommends 27422; AHA Coding Clinic recommends 27566. Confirm with your payer before billing — the disagreement between AMA and AHA Coding Clinic creates real-world variability.

02Can I bill 29873 (arthroscopic lateral release) with 27422 on the same date?

Not without a modifier. NCCI bundles 29873 into 27422 as a column 2 component. If the lateral release was performed as a genuinely distinct service with separate clinical rationale, apply modifier 59 or XS with documentation. Expect scrutiny — payers audit this combination.

03What global period applies to 27422, and what does it cover?

27422 carries a 90-day global period. That includes the day-before visit, the surgery itself, and all routine post-op care through day 90. Any E/M billed in that window for the same condition will be bundled and denied. Use modifier 24 only for a documented, unrelated condition.

04Which ICD-10 codes are typically paired with 27422?

Primary patellar instability or dislocation diagnoses are required — commonly M22.0x (recurrent dislocation of patella) or M22.1x (recurrent subluxation of patella) with the appropriate laterality character. A mismatch between the diagnosis and the reconstruction procedure is a leading denial trigger.

05If the surgeon plans a staged procedure after 27422 within the global period, what modifier applies?

Use modifier 58 for a planned, staged, or related procedure by the same surgeon during the 90-day global. Document the staged intent in the initial operative note. Modifier 58 resets the global clock. Do not use modifier 78 — that is reserved for an unplanned return to the OR for a related complication.

06Is 27422 appropriate for patellofemoral arthroplasty?

No. Patellofemoral arthroplasty (patellar arthroplasty plus trochlear groove resurfacing) is reported with unlisted code 27599 per current AMA guidance. 27422 is a soft-tissue reconstruction code; it does not capture resurfacing of bony articular surfaces.

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 technique name (e.g., Campbell, Goldthwaite, VMO advancement), the specific structures addressed (medial retinaculum, VMO, lateral retinaculum), laterality, and whether an arthroscopic lateral release was performed as a distinct component. That detail prevents the two most common coding errors here: defaulting to 'standard realignment' in the op note — which auditors flag — and missing the NCCI bundle trigger when 29873 is billed alongside 27422 without documented separate clinical necessity.

See how Mira captures CPT 27422 documentation