CPT Code 27447: Total Knee Arthroplasty

Explore CPT code 27447 for total knee arthroplasty, including documentation standards, billing guidance, and related CPT codes.

Use Code

What is CPT code 27447?

The 27447 CPT code refers to a surgical procedure known as total knee arthroplasty (TKA), in which the damaged portions of the knee joint are replaced with an artificial knee joint. It is typically performed to relieve pain and restore function in patients with severe knee arthritis, rheumatoid arthritis, or joint space narrowing that does not respond to non-surgical medical management, such as physical therapy or muscle strengthening exercises.

This code represents a total replacement involving both medial and lateral compartments of the knee, as well as the patellofemoral joint, and includes placement of an internal prosthetic device.

Documentation requirements

To support medical necessity and ensure accurate billing, the following must be documented in the patient's medical record:

Diagnosis and clinical indications: Clearly state the condition (e.g., severe osteoarthritis, rheumatoid arthritis, joint subluxation) causing pain, stiffness, or functional disability.
Failure of conservative therapy: Document prior use of non-surgical medical management, including physical therapy, injections, bracing, and medications, and their insufficient results.
Preoperative imaging and findings: Include radiographic evidence showing joint space narrowing, bone deformity, or degeneration of joint surfaces.
A comprehensive history and physical examination: Include a detailed report outlining the patient’s symptoms, degree of functional limitation, and prior non-surgical treatments attempted. This is essential to demonstrate that surgery is medically necessary and that conservative measures were appropriately addressed.
Physician progress notes: Detail the patient’s symptoms, physical exam findings, and reasons for recommending surgery, confirming that all conservative therapy options have been appropriately addressed.
Informed consent and surgical plan: Ensure the procedure details and risks are discussed with the patient, with documentation in the chart.
Operative report: Include a detailed operative report that describes the surgical approach, prosthetic components implanted, intraoperative findings, and any complications or variations from the planned procedure.

Billing guidelines

Proper billing of CPT 27447 requires compliance with payer-specific rules and consideration of surgical circumstances:

Use 27447 for total knee replacement only: This code applies to total knee arthroplasty involving all compartments. Partial knee replacements (unicompartmental) require different coding.
Report bilateral procedures correctly: If a bilateral knee replacement is performed during the same session, append modifier 50 (for bilateral procedure) or RT/LT as required by payer. Ensure each side is clearly documented. When both knees are replaced, CPT 27447 is billed separately for each knee, with appropriate use of modifiers to reflect the bilateral nature of the procedure.
Same physician, staged procedures: If the same physician performs the procedure on each knee at different times, document the rationale and use appropriate modifiers (e.g., modifier 58 for staged procedures).
Avoid duplication with other services: Do not bill separately for intraoperative imaging or joint manipulation unless distinct and separately documented.
Follow Medicare and commercial guidelines: Confirm if prior authorization is required, especially for Medicare Advantage plans, and ensure supporting documentation aligns with national and local coverage determinations.

Other relevant codes

27446: Arthroplasty, knee, condyle and plateau; medial or lateral compartment
27570: Manipulation of the knee joint under general anesthesia
73564: X-ray, knee, 4 or more views (preoperative imaging)

Frequently asked questions

The CPT code for total knee arthroplasty is 27447. This code represents the surgical replacement of the entire knee joint with a prosthetic implant, typically performed to relieve pain and restore function in patients with severe arthritis or joint degeneration.

CPT 27447 refers to total knee arthroplasty, where all three compartments of the knee—medial, lateral, and patellofemoral—are replaced. In contrast, CPT 27446 is used for unicompartmental (partial) knee arthroplasty, which replaces only one compartment of the knee, usually the medial or lateral side.

No, CPT 27447 is not inpatient-only. While total knee arthroplasty has traditionally been performed in inpatient settings, many payers—including Medicare—now allow it in outpatient settings when the patient meets clinical and safety criteria. Surgical setting should be based on medical necessity and payer guidelines.

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