Summary & Overview
HCPCS L5611: Endoskeletal Above-Knee Knee-Disarticulation 4-Bar Friction Knee
HCPCS Level II code L5611 denotes an endoskeletal prosthetic addition for a lower extremity at the above-knee/knee disarticulation level incorporating a 4-bar linkage with friction swing phase control. This mechanical knee component is significant because it affects mobility, stability, and functional outcomes for patients requiring transfemoral or knee-disarticulation prostheses. Nationally, appropriate coding of prosthetic components influences benefit coverage determinations, claims processing, and access to suitable devices.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical intent and typical delivery settings, plus documentation and billing considerations relevant to prosthetic knee components. The publication outlines benchmarks where available, highlights common payer coverage pathways, and summarizes policy themes that affect authorization and reimbursement for mechanical knee joint additions. Clinical context addresses the role of 4-bar linkage and friction swing control in gait mechanics, while the policy sections focus on coding accuracy, medical necessity documentation, and service-line implications for prosthetics providers and suppliers.
Data not available in the input for associated taxonomies, specific ICD-10 diagnoses, related codes, and payer-specific fee benchmarks is noted where applicable.
Billing Code Overview
HCPCS Level II code L5611 describes an addition to a lower extremity, endoskeletal prosthetic system designed for an above-knee — knee disarticulation amputation level. The component features a 4-bar linkage with friction swing phase control, indicating a mechanical knee joint insert intended to provide stability and controlled swing during gait.
Service Type: Prosthetic component — lower extremity, knee joint addition
Typical Site of Service: Prosthetics/orthotics clinic or outpatient prosthetic fitting center
Clinical & Coding Specifications
Clinical Context
A 58-year-old patient with a prior transfemoral amputation and subsequent knee disarticulation presents for fitting of an endoskeletal above-knee prosthetic component. The patient ambulates at a community ambulation level with variable cadence and requires a stable knee joint that allows swing-phase control and adjustable friction for safer gait on level and uneven surfaces. The prosthetist performs a focused evaluation, takes measurements and casts or scans the residual limb, selects a 4-bar linkage knee with friction swing-phase control to optimize stability and stance-phase support, orders the L5611 addition to the existing lower extremity endoskeletal system, and schedules alignment, fitting, and gait training visits. Typical workflow steps: prosthetic evaluation → component selection and justification in the plan of care → fabrication and assembly of the endoskeletal system with the L5611 knee unit → initial fitting and alignment visit → follow-up adjustments and gait training. Typical site of service is an outpatient prosthetics and orthotics clinic or an ambulatory specialty prosthetic fabrication facility. Typical patient scenario includes post-amputation rehabilitation after knee disarticulation, mechanical instability with prior components, or need for a more durable 4-bar knee with friction swing-phase control to manage gait deviations and safety concerns.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
LT |