Is ICD-10-CM code M65 billable?

No, M65 (Synovitis and tenosynovitis) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code M65 belong to?

M65 belongs to Chapter 13 of the ICD-10-CM tabular list: M00–M99 (Diseases of the Musculoskeletal System and Connective Tissue).

M65Not billable, use a more specific code below

Synovitis and tenosynovitis

In Disorders of synovium and tendon (M65-M67), chapter 13: Diseases of the Musculoskeletal System and Connective Tissue

133 billable codes under M65: none are a CC or MCC; none map to an HCC.

Instructional notes

Excludes1: not coded here, use a different code

chronic crepitant synovitis of hand and wrist (M70.0-)
current injury - see injury of ligament or tendon by body region
soft tissue disorders related to use, overuse and pressure (M70.-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers site and laterality, acute injury versus chronic musculoskeletal conditions, 7th characters for pathologic fractures, osteoporosis with or without current fracture, and multisystem inflammatory syndrome.

Site and laterality (page 60)
Acute traumatic versus chronic or recurrent musculoskeletal conditions (page 61)
Coding of Pathologic Fractures (page 61)
Osteoporosis (page 61)
Multisystem Inflammatory Syndrome (page 62)

Read Section I.C.13 (page 60)

All codes under M65

M65 can't be used on a claim. Pick a billable code below; grey headings group them.

M65 MS-DRGs

As the principal diagnosis, all 133 billable codes under M65 group to MS-DRG 557 or 558 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Arthritis

If you feel pain and stiffness in your body or have trouble moving around, you might have arthritis. Any disorder that affects the joints is often called arthritis. Joints are places where two bones meet, such as your elbow or knee.

Connective Tissue Disorders

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.