M65.9 – Synovitis and tenosynovitis, unspecified

ICD-10-CM 2027 diagnosis code · Disorders of synovium and tendon

Non-billable header

ICD-10-CM code M65.9

Code: M65.9 (claims format: M659)
Description: Synovitis and tenosynovitis, unspecified
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 13. Diseases of the musculoskeletal system and connective tissue (M00-M99)
Block: M65-M67 Disorders of synovium and tendon
Parent codes: M65

Billable codes under M65.9

M65.9 is a header code and cannot be used on claims. Choose the most specific code:

M65.90 – Unspecified synovitis and tenosynovitis, unspecified siteBillable
M65.91 – Unspecified synovitis and tenosynovitis, shoulderHeader (more codes below)
M65.92 – Unspecified synovitis and tenosynovitis, upper armHeader (more codes below)
M65.93 – Unspecified synovitis and tenosynovitis, forearmHeader (more codes below)
M65.94 – Unspecified synovitis and tenosynovitis, handHeader (more codes below)
M65.95 – Unspecified synovitis and tenosynovitis, thighHeader (more codes below)
M65.96 – Unspecified synovitis and tenosynovitis, lower legHeader (more codes below)
M65.97 – Unspecified synovitis and tenosynovitis, ankle and footHeader (more codes below)
M65.98 – Unspecified synovitis and tenosynovitis, other siteBillable
M65.99 – Unspecified synovitis and tenosynovitis, multiple sitesBillable

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

M65 – Synovitis and tenosynovitis

Excludes1 (not coded here):

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.-)

Related codes in M65

M65.0 – Abscess of tendon sheathHeader
M65.1 – Other infective (teno)synovitisHeader
M65.2 – Calcific tendinitisHeader
M65.3 – Trigger fingerHeader
M65.4 – Radial styloid tenosynovitis [de Quervain]Billable
M65.8 – Other synovitis and tenosynovitisHeader

Frequently asked questions

What is ICD-10 code M65.9?

M65.9 is the ICD-10-CM code for synovitis and tenosynovitis, unspecified, in the block M65-M67 (Disorders of synovium and tendon).

Is M65.9 a billable code?

No. M65.9 is a header code with more specific child codes; report one of the billable codes listed above.

What category does M65.9 belong to?

It belongs to category M65 – Synovitis and tenosynovitis.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.