CPT 01400: Anesthesia for Open or Arthroscopic Knee Procedure
CPT code 01400 designates anesthesia services for patients undergoing open or arthroscopic procedures on the knee joint. This code is important for surgical case capture, anesthesia documentation, and national billing consistency for knee surgeries ranging from diagnostic arthroscopy to more extensive open knee procedures. Accurate use of this code affects provider reimbursement, institutional billing workflows, and payor claim adjudication for perioperative anesthesia care.
Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, United Healthcare, and Medicare. Readers will find a concise overview of the clinical context for anesthesia during knee procedures, common claim relationships with knee arthroscopy and repair codes, typical sites of service, and the payer mix considered. The publication highlights benchmarks and coding considerations relevant to anesthesia services for knee surgery, including common companion procedure codes and typical diagnosis pairings used to support medical necessity.
This summary is intended for a national audience of billing managers, anesthesia providers, and revenue cycle professionals seeking a clear reference for CPT code 01400, its clinical role in knee surgery cases, and the payer landscape that influences claim processing and coverage determinations.
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Billing Code Overview
CPT code 01400 describes anesthesia services provided for a patient undergoing an open or arthroscopic procedure on the knee joint. The service type is anesthesia for knee surgery. The typical site of service is an operating room or ambulatory surgical center where open or arthroscopic knee procedures are performed.
Clinical & Coding Specifications
Clinical Context
A 58-year-old patient presents with progressive right knee pain, mechanical symptoms, and limited function. Imaging confirms a meniscal tear with early osteoarthritic changes (S83.241A, M17.11). The orthopedic surgeon schedules an arthroscopic knee procedure (meniscectomy and chondroplasty). The anesthesiology team provides anesthesia for the open or arthroscopic knee procedure billed with 01400. Typical workflow: preoperative evaluation by anesthesia (medical history, airway assessment, ASA classification, and informed consent); intraoperative management (general anesthesia with endotracheal tube or laryngeal mask airway, or monitored anesthesia care with regional blockade such as femoral nerve block or adductor canal block); documentation of anesthetic start and end times, agents used, airway device, monitoring, and intraoperative events; postoperative handoff to PACU with multimodal analgesia plan and documentation of recovery and complications. Typical site of service is an outpatient ambulatory surgery center or hospital operating room. Typical service type is provision of anesthesia care for knee arthroscopy or open knee surgery.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when anesthesia services required substantially greater effort or complexity than usual and documentation supports increased work. |
23 | Unusual anesthesia | Use when general anesthesia is medically necessary for a procedure that is normally performed with local or regional anesthesia. |
50 | Bilateral procedure | Use when bilateral knee procedures are performed and payer allows bilateral anesthesia reporting. |
52 | Reduced services | Use when anesthesia services are partially reduced or incomplete, with supporting documentation. |
53 | Discontinued procedure | Use when the procedure is started but discontinued for reasons documented (e.g., intraoperative complication). |
54 | Surgical care only | Use when the anesthesia provider documents only the surgical portion care if multiple providers split services (rare for anesthesia billing). |
55 | Postoperative management only | Use when provider only delivers postoperative anesthesia management. |
62 | Two surgeons | Use when two surgeons work together as primary surgeons; may affect anesthetic time reporting in complex cases. |
78 | Unplanned return to OR following initial procedure | Use when patient returns to OR for related procedure during global period and anesthesia is provided for the return trip. |
QS | Monitored anesthesia care service | Use when MAC is provided and payer requires QS to identify coverage of non-CRNA MAC services. |
AA | Anesthesia service by an anesthesiologist | Use when service is personally performed by an MD/DO anesthesiologist. |
AD | Medical supervision by a physician; more than four concurrent anesthesia procedures | Use when an anesthesiologist supervises multiple concurrent CRNAs beyond typical ratios and documentation supports billing. |
QX | CRNA service with medical direction by a physician | Use when a CRNA performs services under physician direction meeting medical direction criteria. |
QK | Medical direction of two, three, or four concurrent anesthesia procedures | Use when an anesthesiologist medically directs multiple concurrent CRNAs and meets CMS medical direction requirements. |
XE | Separate encounter | Use when a distinct procedural service during a separate encounter is performed and documentation shows a separate session. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207L00000X | Anesthesiology | Physician anesthesiologists who provide preoperative assessment, intraoperative anesthesia, and postoperative management. |
367H00000X | Anesthesiologist Assistant | Anesthesiologist assistants delivering anesthesia under the direction of an anesthesiologist; documentation must reflect supervision. |
367500000X | Certified Registered Nurse Anesthetist | CRNAs providing anesthesia care; billing may require modifiers (QX, QZ, QK) per payer rules. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
M23.50 | Chronic instability of knee, unspecified knee | Indicates chronic ligamentous or structural instability that may require arthroscopic evaluation or repair under anesthesia. |
M17.11 | Unilateral primary osteoarthritis, right knee | Degenerative joint disease often leading to arthroscopic debridement or preparation for replacement; anesthesia required for operative management. |
M17.12 | Unilateral primary osteoarthritis, left knee | Same clinical relevance for the left knee; informs laterality and procedure planning. |
S83.241A | Other tear of medial meniscus, current injury, right knee, initial encounter | Acute meniscal tear commonly treated with arthroscopic meniscectomy or repair; directly associated with anesthesia services in knee arthroscopy. |
S83.242A | Other tear of medial meniscus, current injury, left knee, initial encounter | Acute medial meniscal tear of the left knee requiring arthroscopic intervention; justifies anesthetic services billed with 01400. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
29877 | Arthroscopy, knee, surgical; debridement/shaving of articular cartilage (chondroplasty) | Common arthroscopic procedure performed during knee surgery for cartilage lesions; anesthesia 01400 covers anesthetic care for this procedure. |
29880 | Arthroscopy, knee, surgical; with meniscectomy (medial AND lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty) | More extensive arthroscopic meniscectomy often performed for complex or combined meniscal pathology; anesthesia services billed under 01400 for intraoperative care. |
29881 | Arthroscopy, knee, surgical; with meniscectomy (medial OR lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty) | Commonly paired with 01400 when a single-compartment meniscectomy is performed; impacts anesthetic time and analgesic plan. |
64447 | Injection(s), anesthetic agent(s) and/or steroid; femoral nerve, including imaging guidance, when performed | Regional nerve block frequently used as adjunct for intraoperative anesthesia and postoperative analgesia; may be performed by anesthesia or proceduralist and documented alongside 01400 when performed by anesthesia provider. |