CPT 01420: Anesthesia for Cast Involving Knee Joint
CPT code 01420 denotes anesthesia services provided when a patient undergoes application, removal, or repair of a cast that includes the knee joint. This code captures anesthesia care tied to orthopedic casting procedures involving the knee and is relevant for billing, care coordination, and procedure-level quality measurement across inpatient and ambulatory surgical settings. Nationally, accurate use of the code affects payment integrity, anesthesia staffing, and perioperative reporting for knee-related orthopedic care.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The analysis covers payer coverage conventions and typical site-of-service considerations for anesthesia billed with cast procedures involving the knee.
Readers will find: an overview of the clinical context for anesthesia during knee-including cast procedures; guidance on common billing relationships and related orthopedic procedure codes for clinical correlation; and a summary of typical payer coverage patterns and documentation considerations. The content helps coding, billing, and clinical teams align anesthesia service reporting with procedural care for knee casting without offering treatment recommendations. Data not available in the input is noted where applicable.
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Billing Code Overview
CPT code 01420 describes anesthesia services for application, removal, or repair of a cast that includes the knee joint. The service involves administration and management of anesthesia during procedures specifically addressing casting that involves the knee.
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Service type: Anesthesia for cast application, removal, or repair involving the knee joint
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Typical site of service: Hospital operating room, ambulatory surgical center, or other procedural setting where anesthesia services are delivered for orthopedic casting involving the knee joint
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with progressive right knee pain from unilateral primary osteoarthritis (M17.11) presents for total knee arthroplasty. Intraoperative management requires general endotracheal anesthesia with a peripheral nerve block for postoperative analgesia. The anesthesia provider is billed under 01420 when anesthesia services are performed for application or removal of a cast that includes the knee joint (for example, when a postoperative immobilizing cast or brace that encompasses the knee must be applied, adjusted, or removed in the perioperative period). Typical workflow: preoperative evaluation by the anesthesia team, documentation of medical comorbidities and ASA physical status (e.g., P3), performance of neuraxial or general anesthesia and any peripheral nerve block, coordination with orthopedics for cast application or removal in the operating room or procedure suite, monitoring during the procedure, and immediate postoperative handoff in PACU. Services may occur in an ambulatory surgery center, hospital outpatient department, or inpatient operating room depending on the primary surgical procedure and patient status.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when anesthesia complexity significantly exceeds usual requirements (document increased work). |
23 | Unusual anesthesia | Use when anesthesia is provided for an emergency major procedure that is ordinarily elective. |
50 | Bilateral procedure | Use when services involve bilateral application/removal of casts including both knees. |
52 | Reduced services | Use when anesthesia service is partially reduced or not completed as planned. |
53 | Discontinued procedure | Use when anesthesia is discontinued due to patient safety or unforeseen circumstances. |
54 | Surgical care only | Use when another clinician provides only the surgical portion and anesthesia is billed separately. |
55 | Postoperative management only | Use when anesthesia provider only furnished postoperative management. |
62 | Two surgeons or more | Use when two surgeons are required and documented for the procedure involving the knee and cast. |
78 | Return to the OR for a related procedure following initial anesthesia | Use when patient returns to OR for a related procedure requiring additional anesthesia care. |
AA | Anesthesia services performed personally by anesthesiologist | Use to indicate physician personally performed the anesthesia service. |
AD | Medical supervision by a physician; more than four concurrent anesthesia procedures | Use when supervising physician oversees >4 concurrent anesthesia procedures. |
AS | Physician service for sole anesthesiologist in cardiac procedure | Use only when applicable cardiac anesthesia context; generally not typical for routine knee cast services. |
QK | Medical direction of two, three, or four CRNAs by anesthesiologist | Use when anesthesiologist medically directs multiple CRNAs for the case. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207L00000X | Anesthesiology | Physician anesthesiologists who provide comprehensive anesthesia care for orthopedic procedures involving the knee and cast management. |
367500000X | Certified Registered Nurse Anesthetist | CRNAs who deliver anesthesia services in OR, ambulatory, and procedural settings for cast-related procedures. |
207RA0401X | Anesthesiology Assistant | Anesthesiology assistants who support the anesthesiologist in delivering anesthesia care for these procedures. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
M23.50 | Chronic instability of knee, unspecified knee | Instability may require surgical stabilization with postoperative immobilization including a cast that covers the knee; 01420 applies when anesthesia is provided for cast care. |
M17.11 | Unilateral primary osteoarthritis, right knee | Degenerative disease leading to procedures such as total knee arthroplasty where a postoperative cast including the knee may be applied or removed under anesthesia. |
M17.12 | Unilateral primary osteoarthritis, left knee | Same clinical relevance as M17.11 for the left knee. |
S83.241A | Other tear of medial meniscus, current injury, right knee, initial encounter | Acute meniscal tear treated with arthroscopy or repair that may require perioperative cast application/removal under anesthesia. |
S83.242A | Other tear of medial meniscus, current injury, left knee, initial encounter | Same relevance as S83.241A for the left knee. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
29881 | Arthroscopy, knee, surgical; with meniscectomy (medial OR lateral, including any meniscal shaving) | May be the primary orthopedic procedure for which anesthesia is provided; cast application or removal may occur perioperatively. |
29880 | Arthroscopy, knee, surgical; with meniscectomy (medial AND lateral, including any meniscal shaving) | Used when more extensive meniscal work is performed; anesthesia services for knee cast care may be billed with 01420 if cast includes knee. |
27447 | Arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing (total knee arthroplasty) | Major procedure often requiring postoperative immobilization with a cast or brace that includes the knee; anesthesia services for cast application/removal fall under 01420. |
20610 | Arthrocentesis, aspiration and/or injection into a major joint or bursa (e.g., shoulder, hip, knee joint) | Diagnostic or therapeutic joint injection may occur in the same episode; anesthesia for cast-related manipulation may be billed separately. |
29877 | Arthroscopy, knee, surgical; debridement/shaving of articular cartilage (chondroplasty) | Debridement procedures may be concurrent with cast application or removal; anesthesia services for cast work are reported with 01420. |