ICD-10 Code M02.361 – Reiter’s disease, right knee (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M02.361 – Reiter’s disease, right knee
What it is
M02.361 identifies Reiter’s disease, also called reactive arthritis, affecting the right knee. Use it when documentation specifies this post-infectious inflammatory arthritis in that joint.
Clinical signs
Typical findings include joint pain, swelling, stiffness, and reduced range of motion in the right knee. Clinical features vary; refer to documentation.
When to use this code
Use M02.361 when the provider documents Reiter’s disease or reactive arthritis limited to the right knee. It is appropriate when the record clearly links the condition to that joint, even if the triggering infection is noted elsewhere. If laterality or the specific diagnosis is unclear, check documentation.
Do not use for
Do not use this code for nonspecific knee pain, traumatic arthritis, or inflammatory arthritis without documentation of Reiter’s disease. Do not assign it when the affected side is not the right knee.
Coding tip
Verify both the diagnosis and laterality in the provider note before coding.