ICD-10 Code M00.169 – Pneumococcal arthritis, unspecified knee (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.169 – Pneumococcal arthritis, unspecified knee
What it is
M00.169 identifies pneumococcal infection of the knee joint when the affected knee is not specified as right or left. Use this code for septic arthritis caused by Streptococcus pneumoniae in the knee.
Clinical signs
Typical findings include an acutely painful, swollen, warm knee with limited range of motion. Clinical features vary; refer to documentation for organism confirmation and whether the infection is confirmed in the joint.
When to use this code
Use this code when the provider documents pneumococcal septic arthritis involving the knee and does not specify laterality. It is appropriate when the knee joint infection is confirmed and the record identifies Streptococcus pneumoniae as the cause. If the documentation only says suspected infection, check documentation before coding.
Do not use for
Do not use it for arthritis of another cause, such as noninfectious inflammatory arthritis or a different organism. Do not assign it if the knee is not documented or if laterality is specified and a more specific code applies.
Coding tip
Confirm both the infectious organism and the joint site in the provider note before selecting this code.