M06.36 Rheumatoid nodule, knee

ICD-10-CM M06.36: Rheumatoid nodule, knee

ICD-10-CM code M06.36 identifies a rheumatoid nodule located in the knee. The terminology record is active and classifies the concept as a finding. Rheumatoid nodules are recognized extra-articular manifestations of rheumatoid arthritis that can develop near joints, including the patella. 1 2

Plain-language overview

Rheumatoid arthritis is a systemic autoimmune disease that involves inflammatory arthritis and extra-articular involvement, which includes manifestations outside the joints. 2

Rheumatoid nodules are the most common extraarticular manifestations of rheumatoid arthritis and may occur over pressure points such as the patella and the joints of the hands and feet. 2

What this code represents

The ICD-10-CM terminology record lists M06.36 with the preferred name rheumatoid nodule, knee, assigns it a semantic type of finding, and maintains an active record status. 1

Coding details

The M06.3 parent concept includes distinct child codes for specific anatomical locations, such as M06.36 for the knee, M06.31 for the shoulder, and M06.39 for multiple sites. 3

Documentation considerations

Clinical literature notes that rheumatoid nodules initially present with a small vessel vasculitis phenomenon followed by a chronic inflammatory granulomatous phase involving the dermis or subcutis. 2

The surrounding dermis and hypodermis of rheumatoid nodules have a perivascular infiltrate of plasma cells, and very occasionally these nodules may occur in the lungs. 2

What the sources add

While the official terminology record defines the specific code label and active status, the clinical literature provides the pathological context of how rheumatoid nodules develop in rheumatoid arthritis. 1 2

A separate rheumatology code listing includes various knee-related rheumatoid arthritis manifestations, such as rheumatoid lung disease and rheumatoid vasculitis with arthritis of the right or left knee. 4

Sources

1. ICD-10-CM M06.36 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. Rheumatology ICD 10 Codes - Rheumatology Advisor — rheumatologyadvisor.com; accessed 2026-07-27.
5. M06.36 - Rheumatoid nodule, knee | ICD-10-CM — unboundmedicine.com; accessed 2026-07-27.