ICD-10-CM Code M77.50

Other enthesopathy of unspecified foot and ankle

Version 2020 Billable Code Revised Code

Valid for Submission

M77.50 is a billable code used to specify a medical diagnosis of other enthesopathy of unspecified foot and ankle. The code is valid for the year 2020 for the submission of HIPAA-covered transactions. The ICD-10-CM code M77.50 might also be used to specify conditions or terms like bursitis of foot region, disorder of flexor hallucis longus tendon, enthesopathy of ankle and/or tarsus, enthesopathy of lower leg and ankle region, intermetatarsal bursitis, tendinitis of flexor hallucis longus, etc

Short Description:Other enthesopathy of unspecified foot and ankle
Long Description:Other enthesopathy of unspecified foot and ankle

Revised 2020 ICD-10 Code

M77.50 was revised for the FY 2020, effective October 1, 2019.


The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Bursitis of foot region
  • Disorder of flexor hallucis longus tendon
  • Enthesopathy of ankle AND/OR tarsus
  • Enthesopathy of lower leg and ankle region
  • Intermetatarsal bursitis
  • Tendinitis of flexor hallucis longus
  • Tendinitis of foot
  • Tendinitis of metatarsophalangeal joint of second toe

Diagnostic Related Groups

The ICD-10 code M77.50 is grouped in the following groups for version MS-DRG V37.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2019 through 09/30/2020.


Convert M77.50 to ICD-9

  • 726.79 - Ankle enthesopathy NEC (Approximate Flag)

Code Classification

  • Diseases of the musculoskeletal system and connective tissue (M00–M99)
    • Other soft tissue disorders (M70-M79)
      • Other enthesopathies (M77)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - Code Updated, effective from 10/1/2019 through 9/30/2020
    • New Description: Other enthesopathy of unspecified foot and ankle
    • Previous Description: Other enthesopathy of unspecified foot

Information for Patients

Foot Injuries and Disorders

Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:

  • Bunions - hard, painful bumps on the big toe joint
  • Corns and calluses - thickened skin from friction or pressure
  • Plantar warts - warts on the soles of your feet
  • Fallen arches - also called flat feet

Ill-fitting shoes often cause these problems. Aging and being overweight also increase your chances of having foot problems.

[Learn More]