2026 ICD-10-CM Diagnosis Code T84.53XAInfection and inflammatory reaction due to internal right knee prosthesis, initial encounter
T84.53XA is a billable ICD-10-CM diagnosis code for infection and inflammatory reaction due to internal right knee prosthesis, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 485 through 487, 559 through 561. Coders also document this condition as infection associated with prosthesis of right knee joint. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of internal orthopedic device or implant, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Infection associated with prosthesis of right knee joint
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Complications of internal orthopedic prosthetic devices, implants and grafts (T84). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Knee Replacement
Knee replacement surgery is a surgery to replace parts of your knee joint with new, artificial parts. You may need a knee replacement if you have knee damage that causes severe pain and difficulty doing daily activities, such as walking and climbing stairs. It is usually done when other treatments for knee pain haven't helped enough.
The full article covers:
- What is knee replacement surgery?
- What conditions does knee replacement surgery treat?
- What happens during knee replacement surgery?
- What happens after knee replacement surgery?
- What is life like after a knee replacement?
- What are the risks of knee replacement surgery?
- How long does a knee replacement last?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T84.53XA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T84.53XAOverview
Is T84.53XA a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report infection and inflammatory reaction due to internal right knee prosthesis, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T84.53XA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for infection and inflammatory reaction due to internal right knee prosthesis, such as an emergency visit or first evaluation.
What MS-DRG does T84.53XA group to?
When infection and inflammatory reaction due to internal right knee prosthesis, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 485, 486, 487, 559, 560, 561, with relative weights from 0.8039 to 3.2271 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of T84.53XA?
Under the General Equivalence Mappings, infection and inflammatory reaction due to internal right knee prosthesis, initial encounter converts to ICD-9-CM 996.66 (react-inter joint prost). The mapping is approximate, so confirm the match fits the documentation.
