L33318 · Knee Orthoses
Version 63. CMS effective date 01/25/2026. CMS updated 12/04/2025. Contractors on the CMS report: CGS Administrators (DME MAC) and Noridian Healthcare Solutions (DME MAC).
CMS coverage policy citation on the LCD. None
HCPCS · Medicare DME
L1821 Medicare coverage
KNEE ORTHOSIS, ELASTIC WITH CONDYLAR PADS AND JOINTS, WITH OR WITHOUT PATELLAR CONTROL, PREFABRICATED, OFF THE SHELF
Long description on the CMS LCD code table, this read.
Data read from the CMS Coverage API on 2026-10-13. The LCD version is the current final DME MAC LCD on that read. Text below is quoted from those CMS documents. Nothing here is a coverage rule Verzi wrote.
Coverage, in CMS's words
Local coverage indication
A knee orthosis with joints (L1810, L1812) or knee orthosis with condylar pads and joints with or without patellar control (L1820, L1821) are covered for ambulatory beneficiaries who have weakness or deformity of the knee and require stabilization. If an L1810, L1812, L1820 or L1821 is provided but the criteria above are not met, the orthosis will be denied as not reasonable and necessary.
Excerpt from LCD L33318 version 63, effective 01/25/2026. CMS LCD L33318.
Governing LCD
Documentation requirements
From A52465
For a knee orthosis with adjustable knee joints or a prefabricated Swedish type knee orthosis (L1832, L1833, L1850), the medical records must include documentation of the beneficiary’s physical examination of the affected knee(s), including all of the following: The joint laxity test(s) performed; and, A description of the exam findings that support objective joint laxity. For a knee orthosis with single or double upright, adjustable flexion and extension joint, medial-lateral and rotation control, with or without varus/valgus adjustment (L1843, L1844, L1845, L1846, L1851, L1852) for the management of an ambulatory beneficiary with knee instability, the medical records must include documentation of all of the following: The beneficiary’s ambulatory status; and, A physical examination of the affected knee(s), including all of the following: The joint laxity test(s) performed; and, A description of the exam findings that support objective joint laxity.
From A55426, Standard Documentation Requirements for All Claims Submitted to DME MACs
GENERAL There are numerous CMS manual requirements, reasonable and necessary (R&N) requirements, benefit category, and other statutory and regulatory requirements that must be met in order for payment to be justified. In the event of a claim review, a DMEPOS supplier must provide sufficient information to demonstrate that the applicable criteria have been met thus justifying payment. Before submitting a claim to Medicare, the DMEPOS supplier must have on file an SWO, a WOPD (if applicable), information from the treating practitioner concerning the patient's diagnosis, and any information required for the use of specific
Denial language in the policy
- If an L1810, L1812, L1820 or L1821 is provided but the criteria above are not met, the orthosis will be denied as not reasonable and necessary. Source: L33318
- If the supplier bills for an item addressed in this policy without first receiving a completed SWO, the claim shall be denied as not reasonable and necessary. Source: L33318
- If a supplier delivers a DMEPOS item without first receiving a WOPD, the claim shall be denied as not reasonable and necessary. Source: L33318
- In this scenario, if the supplier separately bills for associated options, accessories, and/or supplies without first receiving a completed and signed WOPD of the base item prior to delivery, the claim(s) shall be denied as not reasonable and necessary. Source: L33318
Get the signed answer via API
The signed answer is the receipt for this code on a date of service: the rule that was in force, with a hash you can replay. The call needs an API key. The source archive and as-of resolution are public.
curl -H "X-API-Key: $VERZI_API_KEY" \
"https://api.verzi.health/v1/rules/warrant?hcpcs=L1821&as_of=2024-01-15&npi=1234567890&state=UT"Other codes on the same LCD
Questions about this code
Which LCD lists L1821?
The current DME MAC LCD L33318, Knee Orthoses, version 63, effective 01/25/2026.
What denial language does CMS publish for L1821?
If an L1810, L1812, L1820 or L1821 is provided but the criteria above are not met, the orthosis will be denied as not reasonable and necessary.
How do I get a signed answer for L1821?
Request a free API key and call the signed-answer endpoint with the HCPCS code, a date of service, the supplier NPI, and a state. The response is a receipt for the published rule on that date, not a guarantee of payment.