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ICD-10-CM 2027 diagnosis code

M65.8Other synovitis and tenosynovitis

Not billable — use a more specific code

M65.8 is a header code, so it can't be reported by itself. Choose one of the 10 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M65.8

M65.8 is the ICD-10-CM diagnosis code for other synovitis and tenosynovitis. It belongs to category M65 (synovitis and tenosynovitis), block M65-M67 (disorders of synovium and tendon) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 10 subcodes must be used instead.

Within M65, choose M65.8 (Other synovitis and tenosynovitis) only when documentation doesn't support a more specific option: abscess of tendon sheath (M65.0), other infective (teno)synovitis (M65.1), Calcific tendinitis (M65.2), Trigger finger (M65.3), radial styloid tenosynovitis [de Quervain] (M65.4) and unspecified (M65.9).

To report this condition, pick the subcode that matches the documentation: M65.80 (unspecified site), M65.81 (shoulder), M65.82 (upper arm), M65.83 (forearm), M65.84 (hand), M65.85 (thigh), M65.86 (lower leg), M65.87 (ankle and foot) and 2 more.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under M65.8

Notes that apply from higher levels

Instructions written at a parent level also apply to M65.8.

› From M65 Synovitis and tenosynovitis
Excludes1
  • 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.-)

Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

2 entries

Terms in the official ICD-10-CM index that lead to M65.8.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M65.8

Is M65.8 billable?

No. M65.8 is a header code. Report one of its more specific subcodes instead.