ICD-10-CM 2027
ICD-10 code for tenosynovitis
From the official ICD-10-CM alphabetic index entry “Tenosynovitis”. Page updated September 29, 2026.
About coding tenosynovitis
The ICD-10-CM code for tenosynovitis is M65.90 (Unspecified synovitis and tenosynovitis, unspecified site). The official index lists 30 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on M65.90.
Within M65.9, choose M65.90 (unspecified site) only when documentation doesn't support a more specific option: shoulder (M65.91), upper arm (M65.92), forearm (M65.93), hand (M65.94), thigh (M65.95), lower leg (M65.96), ankle and foot (M65.97), other site (M65.98) and 1 more.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 557 (Tendonitis, Myositis and Bursitis with MCC, relative weight 1.489) and DRG 558 (Tendonitis, Myositis and Bursitis without MCC, relative weight 0.8875), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific tenosynovitis codes (official index)
- adhesive
- shoulder
- bicipital (calcifying)
- gonococcal A54.49 — Gonococcal infection of other musculoskeletal tissue
- in (due to)
- crystals M65.8 — Other synovitis and tenosynovitis
- gonorrhea A54.49 — Gonococcal infection of other musculoskeletal tissue
- syphilis (late) A52.78 — Syphilis of other musculoskeletal tissue
- use, overuse, pressure
- specified NEC
- infective NEC M65.1 — Other infective (teno)synovitis
- ankle M65.17 — Other infective (teno)synovitis, ankle and foot
- foot M65.17 — Other infective (teno)synovitis, ankle and foot
- forearm M65.13 — Other infective (teno)synovitis, wrist
- hand M65.14 — Other infective (teno)synovitis, hand
- lower leg M65.16 — Other infective (teno)synovitis, knee
- multiple sites M65.19 — Other infective (teno)synovitis, multiple sites
- pelvic region M65.15 — Other infective (teno)synovitis, hip
- shoulder region M65.11 — Other infective (teno)synovitis, shoulder
- specified site NEC M65.18 — Other infective (teno)synovitis, other site
- thigh M65.15 — Other infective (teno)synovitis, hip
- upper arm M65.12 — Other infective (teno)synovitis, elbow
- radial styloid M65.4 — Radial styloid tenosynovitis [de Quervain]
- shoulder region M65.81 — Other synovitis and tenosynovitis, shoulder
- adhesive
- specified type NEC M65.88 — Other synovitis and tenosynovitis, other site
- ankle M65.87 — Other synovitis and tenosynovitis, ankle and foot
- foot M65.87 — Other synovitis and tenosynovitis, ankle and foot
- forearm M65.83 — Other synovitis and tenosynovitis, forearm
- hand M65.84 — Other synovitis and tenosynovitis, hand
- lower leg M65.86 — Other synovitis and tenosynovitis, lower leg
- multiple sites M65.89 — Other synovitis and tenosynovitis, multiple sites
- pelvic region M65.85 — Other synovitis and tenosynovitis, thigh
- shoulder region M65.81 — Other synovitis and tenosynovitis, shoulder
- specified site NEC M65.88 — Other synovitis and tenosynovitis, other site
- thigh M65.85 — Other synovitis and tenosynovitis, thigh
- upper arm M65.82 — Other synovitis and tenosynovitis, upper arm
- tuberculous
Common questions about tenosynovitis ICD-10 codes
What is the ICD-10 code for tenosynovitis?
- M65.90 — Unspecified synovitis and tenosynovitis, unspecified site. More specific codes apply when the documentation supports them: A54.49, M65.8, A54.49, A52.78 and others below.
What is the ICD-10 code for gonococcal tenosynovitis?
- A54.49 — Gonococcal infection of other musculoskeletal tissue.
What is the ICD-10 code for infective nec tenosynovitis?
- M65.1 — Other infective (teno)synovitis (header code; choose a more specific subcode).
What is the ICD-10 code for radial styloid tenosynovitis?
- M65.4 — Radial styloid tenosynovitis [de Quervain].
What is the ICD-10 code for shoulder region tenosynovitis?
- M65.81 — Other synovitis and tenosynovitis, shoulder (header code; choose a more specific subcode).
Is M65.90 billable?
- Yes. M65.90 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M65.90 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M65.90 as a principal diagnosis.
Is M65.90 a CC or MCC?
- No. M65.90 is neither a CC nor an MCC under MS-DRG v44.0.