ICD-10-CM 2027 diagnosis code
M65Synovitis and tenosynovitis
M65 is a header code, so it can't be reported by itself. Choose one of the 7 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
M65 is the ICD-10-CM diagnosis code for synovitis and tenosynovitis. It belongs to 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 7 subcodes must be used instead.
To report this condition, pick the subcode that matches the documentation: M65.0 (sheath), M65.1 ((teno)synovitis), M65.2 (tendinitis), M65.3 (finger), M65.4 (Quervain]), M65.8 (tenosynovitis) and M65.9 (unspecified).
Don't report M65 together with the conditions in its Excludes1 note: chronic crepitant synovitis of hand and wrist (M70.0-), current injury - see injury of ligament or tendon by body region and soft tissue disorders related to use, overuse and pressure (M70.-).
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
- M65.0Abscess of tendon sheath
- M65.00Abscess of tendon sheath, unspecified siteBillable
- M65.01Abscess of tendon sheath, shoulder
- M65.02Abscess of tendon sheath, upper arm
- M65.03Abscess of tendon sheath, forearm
- M65.04Abscess of tendon sheath, hand
- M65.05Abscess of tendon sheath, thigh
- M65.06Abscess of tendon sheath, lower leg
- M65.07Abscess of tendon sheath, ankle and foot
- M65.08Abscess of tendon sheath, other siteBillable
- M65.1Other infective (teno)synovitis
- M65.10Other infective (teno)synovitis, unspecified siteBillable
- M65.11Other infective (teno)synovitis, shoulder
- M65.12Other infective (teno)synovitis, elbow
- M65.13Other infective (teno)synovitis, wrist
- M65.14Other infective (teno)synovitis, hand
- M65.15Other infective (teno)synovitis, hip
- M65.16Other infective (teno)synovitis, knee
- M65.17Other infective (teno)synovitis, ankle and foot
- M65.18Other infective (teno)synovitis, other siteBillable
- M65.19Other infective (teno)synovitis, multiple sitesBillable
- M65.2Calcific tendinitis
- M65.20Calcific tendinitis, unspecified siteBillable
- M65.22Calcific tendinitis, upper arm
- M65.23Calcific tendinitis, forearm
- M65.24Calcific tendinitis, hand
- M65.25Calcific tendinitis, thigh
- M65.26Calcific tendinitis, lower leg
- M65.27Calcific tendinitis, ankle and foot
- M65.28Calcific tendinitis, other siteBillable
- M65.29Calcific tendinitis, multiple sitesBillable
- M65.3Trigger finger
- M65.4Radial styloid tenosynovitis [de Quervain]Billable
- M65.8Other synovitis and tenosynovitis
- M65.80Other synovitis and tenosynovitis, unspecified siteBillable
- M65.81Other synovitis and tenosynovitis, shoulder
- M65.82Other synovitis and tenosynovitis, upper arm
- M65.83Other synovitis and tenosynovitis, forearm
- M65.84Other synovitis and tenosynovitis, hand
- M65.85Other synovitis and tenosynovitis, thigh
- M65.86Other synovitis and tenosynovitis, lower leg
- M65.87Other synovitis and tenosynovitis, ankle and foot
- M65.88Other synovitis and tenosynovitis, other siteBillable
- M65.89Other synovitis and tenosynovitis, multiple sitesBillable
- M65.9Synovitis and tenosynovitis, unspecified
- M65.90Unspecified synovitis and tenosynovitis, unspecified siteBillable
- M65.91Unspecified synovitis and tenosynovitis, shoulder
- M65.92Unspecified synovitis and tenosynovitis, upper arm
- M65.93Unspecified synovitis and tenosynovitis, forearm
- M65.94Unspecified synovitis and tenosynovitis, hand
- M65.95Unspecified synovitis and tenosynovitis, thigh
- M65.96Unspecified synovitis and tenosynovitis, lower leg
- M65.97Unspecified synovitis and tenosynovitis, ankle and foot
- M65.98Unspecified synovitis and tenosynovitis, other siteBillable
- M65.99Unspecified synovitis and tenosynovitis, multiple sitesBillable
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to M65.
Broader instructions also apply from Chapter 13: Diseases of the musculoskeletal system and connective tissue.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about M65
Is M65 billable?
- No. M65 is a header code. Report one of its more specific subcodes instead.