HCPCS Code L1846: Custom-Fabricated Knee Orthosis with Adjustable Flexion/Extension Joint

Use L1846 knee orthosis codes when a custom-fabricated brace is medically necessary due to patient-specific anatomic factors that prevent prefabricated options from providing proper support or fit. Coverage requires meeting all criteria for prefabricated knee orthoses plus the additional justification for custom fabrication, as outlined in the relevant policy article and LCD.

No. Coverage requires objective clinical findings, such as varus/valgus instability or a positive drawer test demonstrating laxity, documented in the patient record and supported by the appropriate ICD-10 diagnosis code. Subjective statements alone are insufficient according to CMS policy and would not meet the criteria for medical necessity.

No. L1846 knee codes are reserved for braces that are truly custom-fabricated from a patient model or template. Minor adjustments made during the fitting of a prefabricated orthosis do not qualify. Bill the appropriate prefabricated code (such as L1845) in those cases, consistent with LCD guidance and the official ICD code coverage tables in the CMS references. Always refer to a valid HCPCS book.