20985

Add-on code for imageless computer-assisted surgical navigation used during musculoskeletal procedures — reported in addition to the primary surgical code.

Verified May 8, 2026 · 7 sources ↓

Medicare: $123.92
Total RVUs: 3.71
Global, days
Region: Multi-region

Drawn from CMSUhcproviderMcgsCgsmedicare

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Specify that an imageless navigation system was used — not fluoroscopy- or CT/MRI-based guidance — to distinguish from 0054T and 0055T.
Identify the navigation platform by name (e.g., Stryker MAKO imageless mode, Brainlab, Exactech) and confirm no preoperative imaging dataset was loaded.
Document the clinical rationale for using computer-assisted navigation, including any alignment targets or intraoperative measurements generated by the system.
Record the primary procedure code being augmented and confirm 20985 is listed as a secondary/add-on code on the claim.
Include intraoperative navigation data printouts or screenshots in the operative record where available — auditors look for objective confirmation that the system was actively used.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

51 Multiple procedures 59 Distinct service XS Separate structure

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 20985 is an add-on code (ZZZ global) reported alongside the primary musculoskeletal procedure when the surgeon uses an imageless computer-assisted navigation system (CANS). Imageless means no preoperative CT or MRI is required to drive the navigation — the system generates real-time three-dimensional anatomical data intraoperatively. Common primary procedures paired with 20985 include total knee arthroplasty (27447), total hip arthroplasty (27130), and unicompartmental knee arthroplasty (27446).

Payer coverage for 20985 is genuinely variable and is the single biggest billing risk for this code. BCBS of Florida classifies computer-assisted navigation for orthopedic procedures as experimental or investigational. UnitedHealthcare has a separate medical policy covering CAN for musculoskeletal procedures. Medicare has no NCD governing 20985; coverage falls to MAC-level LCDs and, where no LCD exists, Medicare Advantage plans may apply their own criteria. CGS Medicare's proposed LCD for total joint arthroplasty (L40232) explicitly includes 20985 in its coding framework, and Noridian's proposed TKA LCD (L36575) similarly addresses it — but neither is universally in effect. Always verify the applicable MAC's current LCD status before billing.

Modifier 51 belongs on 20985 when billing with a primary procedure under most commercial plans; some Medicaid plans have flagged claims for missing anatomical modifiers on the primary code when 20985 is the secondary. Do not report 20985 with 0054T or 0055T for the same session — those image-guided navigation add-ons are mutually exclusive with the imageless variant.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	2.44
Practice expense RVU	0.77
Malpractice RVU	0.5
Total RVU	3.71
Medicare national rate	$123.92
Global period	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	$123.92

Common denial reasons

The recurring reasons claims for CPT 20985 get rejected.

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

Payer classifies computer-assisted navigation as experimental or investigational — BCBS of Florida and some Blue plans do this categorically.
Missing or incorrect modifier: some Medicaid plans deny 20985 when modifier 51 is absent from the secondary code position.
Billing 20985 alongside 0054T or 0055T for the same operative session — these are mutually exclusive navigation add-ons.
No covered primary procedure on the same claim — 20985 is an add-on and cannot stand alone.
MAC LCD not met: CGS and Noridian proposed LCDs include coverage criteria for the primary joint arthroplasty; if the primary is denied, 20985 falls with it.

Frequently asked questions

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

01Can 20985 be billed with 27447 (total knee arthroplasty) on the same claim?

Yes. 20985 is an add-on specifically designed to be reported with a primary musculoskeletal procedure like 27447. List 27447 as the primary and 20985 as secondary with modifier 51 appended to 20985 on most commercial claims.

02What is the difference between 20985, 0054T, and 0055T?

20985 is imageless navigation — no preoperative imaging drives the system. 0054T uses fluoroscopic image guidance. 0055T uses CT or MRI image guidance. Bill only one per operative session based on which system was actually used; they are mutually exclusive.

03Does Medicare cover 20985?

There is no CMS National Coverage Determination for 20985. Coverage depends on the MAC's LCD. Noridian and CGS have proposed or active LCDs addressing 20985 in the context of total joint arthroplasty. Medicare Advantage plans may set their own criteria. Verify your MAC's current LCD status before billing.

04Why would a Medicaid plan deny 20985 for a missing HCPCS modifier?

Some state Medicaid plans — including Superior Health Plan — require a site-specific or anatomical modifier on the primary code (e.g., LT/RT for a joint procedure) as a precondition for processing the secondary add-on. If the primary claim has a modifier error, the add-on denies with it.

05Is 20985 payable in an ASC or HOPD setting?

CMS does not assign a separate ASC or HOPD payment rate for 20985 — it is packaged into the facility payment for the primary procedure. Physician billing (Part B) uses the separate professional fee schedule RVU. Confirm facility-side packaging with your ASC or hospital billing team before expecting a separate facility line-item payment.

06Should modifier 59 or XS be appended to 20985?

Only if a payer NCCI edit flags the 20985/primary procedure pair and the modifier indicator allows override. For most primary orthopedic joint codes, 20985 is a recognized add-on and does not require a 59/XS bypass. Run the pairing through the NCCI PTP lookup before appending.

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 navigation system name, confirms the imageless designation (no preoperative CT/MRI dataset), records intraoperative alignment measurements generated by the system, and links 20985 explicitly to the primary procedure code in the operative note. This prevents the most common audit flag: operative notes that reference 'computer navigation' without specifying imageless versus image-guided, which triggers downcoding to an unlisted code or outright denial.

See how Mira captures CPT 20985 documentation