Summary & Overview
CPT 29871: Arthroscopic Knee Irrigation and Drainage
CPT code 29871 represents arthroscopic irrigation and drainage of the knee joint to evaluate and treat suspected intra‑articular infection. As both a diagnostic and therapeutic procedure, it plays a critical role in early management of septic arthritis and other purulent joint processes; timely surgical washout can affect clinical outcomes and downstream resource use. Nationally, the code is relevant across hospital and ambulatory surgical settings where orthopedic and sports medicine specialists, as well as acute care surgeons, manage septic or suspected septic joints.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise review of the clinical context for use of the code, expected sites of service, and common billing considerations. The publication provides benchmarks and utilization context where available, summarizes relevant policy and coverage considerations that affect access and prior authorization, and outlines typical coding relationships to inpatient and outpatient surgical settings. Data not available in the input is noted where applicable. This summary is intended for billing managers, revenue cycle teams, clinical leaders, and policy analysts seeking a practical national overview of CPT code 29871 and its role in managing knee joint infections.
Billing Code Overview
CPT code 29871 describes an arthroscopic procedure in which the provider inspects the internal structures of the knee joint to evaluate a suspected infection, performs irrigation (washout) of the joint, and drains infected material to remove debris and reduce microbial load. The procedure is diagnostic and therapeutic when used to clear purulent material from the joint space.
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Service type: Arthroscopic knee irrigation and drainage
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Typical site of service: Ambulatory surgical center or hospital operating room
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult who presents to the emergency department or orthopaedic clinic with acute onset knee pain, swelling, fever, and limited range of motion suspicious for septic arthritis. The patient often has elevated inflammatory markers (e.g., ESR, CRP), joint effusion on physical exam and ultrasound, and synovial fluid aspiration that is purulent or shows a high white blood cell count. After initial evaluation and attempted aspiration, the orthopaedic surgeon schedules an arthroscopic irrigation and debridement of the knee to inspect the intra-articular structures, obtain intraoperative cultures, wash out purulent material, and place drains if indicated.
The clinical workflow includes preoperative evaluation (history, focused exam, labs, and imaging), informed consent, administration of antibiotics per institutional protocol (often after cultures obtained when possible), operating room arthroscopy under regional or general anesthesia, synovial biopsy/culture collection, arthroscopic lavage and debridement, possible placement of a drain, postoperative monitoring for infection control, and coordination with infectious disease for targeted antimicrobial therapy and follow-up care. Typical site of service is the hospital operating room; ambulatory surgical center use is less common for acute septic presentations.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default/No modifier | Use when no specific modifier applies to the service. |