A4635 Underarm Pad — HCPCS Reimbursement | OpenPayer

Summary & Overview

HCPCS A4635: Underarm Pad, Crutch, Replacement, Each

HCPCS Level II code A4635 denotes an individual replacement underarm pad for crutches, a common durable medical equipment accessory that supports safe ambulation and patient comfort. Nationally, this code matters because it tracks replacement accessories that affect durable medical equipment supply chains, outpatient billing, and patient out-of-pocket costs. Coverage and payment for replacement parts can influence adherence to mobility device use and overall injury prevention.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of coverage and payment patterns for replacement crutch pads, common billing practices, and the clinical context in which A4635 is used. The publication highlights benchmarks for utilization and reimbursement where available, summarizes relevant policy updates affecting durable medical equipment accessories, and explains the service setting and clinical rationale for replacement underarm pads.

This summary is for a national audience and focuses on administrative and clinical relevance rather than state-specific rules. Data not available in the input is noted where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareA4635HCPCS Level IIdurable medical equipmentcrutch accessoryreplacement partoutpatient caremobility devicesmedical billing

Billing Code Overview

HCPCS Level II code A4635 describes an underarm pad, crutch, replacement, each. This item is a single replacement underarm pad intended for use with crutches to provide cushioning and pressure relief for the axillary region during ambulation.

Service type: Durable medical equipment accessory/replacement part
Typical site of service: Outpatient settings, durable medical equipment suppliers, home use

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult using forearm crutches who presents to durable medical equipment (DME) services or an orthotics/prosthetics clinic requiring replacement underarm (axillary) crutch pads due to wear, loss, or skin irritation. The patient may have a chronic lower-extremity injury, recent fracture, joint arthroplasty, or neurologic condition necessitating continued use of crutches. The workflow: clinician or DME supplier verifies patient identity and prescription, documents medical necessity (weight-bearing status, mobility limitations, recent procedure or injury), inspects existing crutches and pads, confirms the appropriate replacement pad model and quantity, obtains payer authorization if required, dispenses replacement pad(s) billed as A4635 with applicable modifier, and documents the item serial number or supplier details in the medical record. Typical site of service is an outpatient clinic, DME supplier location, home health visit, or inpatient discharge planning when patients are discharged with ambulatory aids.

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier	Used when no special circumstances apply and standard billing is appropriate.
`52`

HCPCS A5507: Diabetic Depth-Inlay or Custom-Molded Shoe Modification

HCPCS-A4608-TRANSTRACHEAL-OXYGEN-CATHETER

HCPCS Level II A4608: Transtracheal Oxygen Catheter, Each

HCPCS-A7044-ORAL-INTERFACE-POSITIVE-AIRWAY-PRESSURE-DEVICE

HCPCS A7044: Oral Interface for Positive Airway Pressure Device, Each

HCPCS-A4629-TRACHEOSTOMY-CARE-KIT-ESTABLISHED-TRACHEOSTOMY

HCPCS Level II A4629: Tracheostomy Care Kit for Established Tracheostomy

HCPCS-A4381-URINARY-OSTOMY-POUCH-FACEPLATE-PLASTIC-EACH

HCPCS Level II A4381: Urinary Ostomy Pouch for Faceplate, Plastic, Each

HCPCS-A6554-GRADIENT-COMPRESSION-STOCKING-BELOW-KNEE-40MMHG

HCPCS A6554: Below-Knee Gradient Compression Stocking, 40 mmHg or Greater

HCPCS-LEVEL-II-A4404-OSTOMY-RING

HCPCS Level II A4404: Ostomy Ring, Each

HCPCS-A6251-SPECIALTY-ABSORPTIVE-DRESSING-STERILE-16SQIN

HCPCS A6251: Specialty Absorptive Wound Dressing, Sterile

HCPCS-A6237-HYDROCOLLOID-DRESSING-16SQIN-WOUND-COVER

HCPCS A6237: Hydrocolloid Dressing, Sterile, 16 sq. in. or Less

HCPCS-A4246-BETADINE-PHISOHEX-SOLUTION-PER-PINT

HCPCS A4246: Betadine or Phisohex Solution, Per Pint

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Taxonomy Code	Specialty	Notes
`252N00000X`	Physical Therapist	Evaluates gait and mobility, fits and recommends crutch accessories.
`3336C0002X`	Orthotist/Prosthetist	Fits and dispenses crutch components and ensures proper interface with assistive device.
`261Q00000X`	Physical Medicine & Rehabilitation Physician	Manages functional mobility needs and documents medical necessity for DME.
`207L00000X`	Orthopedic Surgeon	Treats underlying musculoskeletal conditions leading to crutch use and may order replacements.
`193200000X`	DME Supplier	Supplier taxonomy used by durable medical equipment providers who dispense `A4635`.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S82.201A`	Unspecified fracture of shaft of right tibia, initial encounter for closed fracture	Patients with lower-leg fractures commonly require crutches and may need replacement pads during recovery.
`S82.202A`	Unspecified fracture of shaft of left tibia, initial encounter for closed fracture	As above for left-sided injury indicating ongoing crutch use.
`M16.11`	Unilateral primary osteoarthritis, right hip	Postoperative or conservative management with altered weight-bearing may necessitate crutch use and replacement pads.
`M17.12`	Unilateral osteoarthritis, left knee	Knee osteoarthritis causing ambulation limitations leading to crutch dependence and replacement accessories.
`G82.50`	Paraplegia, unspecified	Chronic neurologic conditions impairing gait often require long-term use of crutches or assistive devices and accessory replacements.
`Z74.09`	Other reduced mobility	Functional limitation code supporting need for mobility aids and replacement parts.
`Z96.651`	Presence of right artificial hip joint	Postoperative or prosthetic-related mobility limitations where crutch use and maintenance are required.
`M54.5`	Low back pain	Pain-limited ambulation may prompt temporary crutch use and need for replacement underarm pads.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`99500`	Home visit for provision of equipment or supplies (eg, bandages, catheters) — local payer-specific codes vary	May be used when a clinician provides or documents DME supplies like crutch pads during a home visit; check payer policies.
`97001`	Physical therapy evaluation	Performed to assess mobility needs and justify DME such as crutch pad replacement when functional limitations are documented.
`97110`	Therapeutic exercises	Physical therapy interventions that often accompany crutch use; documentation may support ongoing DME needs.
`99070`	Supplies and materials (eg, surgical dressings), used by physician and not usually billed separately when included in service	Sometimes used by providers to bill small replacement supplies when payer allows; rules vary.
`S9452`	Repair or adjustment of durable medical equipment, per visit	Used when crutch pads are replaced as part of a repair or adjustment service rather than a simple supply replacement.
`A9270`	Non-covered item or service	Used when an item like a replacement pad is considered non-covered by some payers and must be billed to patient; payer policies differ.

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