L4631 — Ankle foot orthosis, walking boot type, varus/valgus correction, rocker bottom, anterior tibial shell, soft interface, custom arch support, plastic or other material, includes straps and closures, custom fabricated
L4631 is a HCPCS Level II code for ankle foot orthosis, walking boot type, varus/valgus correction, rocker bottom, anterior tibial shell, soft interface, custom arch support, plastic or other material, includes straps and closures, custom fabricated. It belongs to the Orthotic and Prosthetic Procedures and Devices section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Carrier judgment
Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.
From the coverage field of the CMS Alpha-Numeric HCPCS File, release 2026Q3-Jul. This states Medicare’s position on the code, not on your particular claim.
Medically Unlikely Edits — units per day
The most units of L4631 Medicare will pay on one date of service. Bill more on a single line and it is denied. The limit is not the same in every setting, so the row that matters is the one matching the claim you are building.
- practitioner
- 0 — never payable MAI 3 — Date of Service Edit: Clinical · CMS Policy
- outpatient
- 2 units MAI 2 — Date of Service Edit: Policy · Anatomic Consideration
- DME supplier
- 2 units MAI 2 — Date of Service Edit: Policy · Anatomic Consideration
The adjudication indicator decides whether exceeding the limit is worth appealing at all: MAI 1 is a line edit you can support with documentation, MAI 3 is a date-of-service edit that is also appealable, and MAI 2 is absolute — no documentation overrides it. CMS MUE 2026Q3.
The CMS record for L4631
- Long descriptor
- Ankle foot orthosis, walking boot type, varus/valgus correction, rocker bottom, anterior tibial shell, soft interface, custom arch support, plastic or other material, includes straps and closures, custom fabricated
- Short descriptor
- Afo, walk boot type, cus fab
- Added
- January 1, 2011
- BETOS
- D1F
- Pricing indicator
- 38 — DMEPOS
The official wording. This is what the code means.
CMS's 28-character form, which is what shows up on a remittance advice.
When CMS introduced the code.
Berenson-Eggers Type of Service — CMS's own analytic grouping.
Orthotics, prosthetics, prosthetic devices and vision services. Price subject to floors and ceilings.
Codes adjacent to L4631
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If L4631 is not quite right, the correct code is very often within a few positions of it.
- L4370Pneumatic full leg splint, prefabricated, off-the-shelf
- L4386Walking boot, non-pneumatic, with or without joints, with or without interface material, prefabricated item that has been trimmed, bent, molded, assembled, or otherwise customized to fit a specific patient by an individual with expertise
- L4387Walking boot, non-pneumatic, with or without joints, with or without interface material, prefabricated, off-the-shelf
- L4392Replacement, soft interface material, static afo
- L4394Replace soft interface material, foot drop splint
- L4396Static or dynamic ankle foot orthosis, including soft interface material, adjustable for fit, for positioning, may be used for minimal ambulation, prefabricated item that has been trimmed, bent, molded, assembled, or otherwise customized to fit a specific patient by an individual with expertise
- L4397Static or dynamic ankle foot orthosis, including soft interface material, adjustable for fit, for positioning, may be used for minimal ambulation, prefabricated, off-the-shelf
- L4398Foot drop splint, recumbent positioning device, prefabricated, off-the-shelf
- L5000Partial foot, shoe insert with longitudinal arch, toe filler
- L5010Partial foot, molded socket, ankle height, with toe filler
- L5020Partial foot, molded socket, tibial tubercle height, with toe filler
- L5050Ankle, symes, molded socket, sach foot
- L5060Ankle, symes, metal frame, molded leather socket, articulated ankle/foot
- L5100Below knee, molded socket, shin, sach foot
- L5105Below knee, plastic socket, joints and thigh lacer, sach foot
- L5150Knee disarticulation (or through knee), molded socket, external knee joints, shin, sach foot
Questions about L4631
What is HCPCS code L4631?
L4631 is a HCPCS Level II code for ankle foot orthosis, walking boot type, varus/valgus correction, rocker bottom, anterior tibial shell, soft interface, custom arch support, plastic or other material, includes straps and closures, custom fabricated. It sits in the Orthotic and Prosthetic Procedures and Devices section.
Does Medicare cover L4631?
The CMS HCPCS file marks L4631 as "Carrier judgment". Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.