M79.4 Hypertrophy of (infrapatellar) fat pad

✓ Billable ICD-10-CM 2026
Open M79.4 in Web App →

The ICD-10-CM code for Hypertrophy of (infrapatellar) fat pad is M79.4 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Section
M70-M79: Other soft tissue disorders (M70-M79)
Category M79
66 codes (52 billable)
FY2026 Status
Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to M79.4:

  • Fibrosis, fibrotic › popliteal fat pad
  • Fibrosis, fibrotic › infrapatellar fat pad
  • Degeneration, degenerative › infrapatellar fat pad
  • Degeneration, degenerative › popliteal fat pad
  • Fat › localized (pad) › knee
  • Fat › pad › knee
  • Fat › localized (pad) › retropatellar
  • Hypertrophy, hypertrophic › fat pad › knee (infrapatellar) (popliteal) (prepatellar) (retropatellar)

U.S. Hospital Utilization

  • An estimated 125 U.S. inpatient stays in 2023 included M79.4 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Osteoporosis without pathological fracture (M81)

Category M81, Osteoporosis without current pathological fracture, is for use for patients with osteoporosis who do not currently have a pathologic fracture due to the osteoporosis, even if they have had a fracture in the past. For patients with a history of osteoporosis fractures, status code Z87.310, Personal history of (healed) osteoporosis fracture, should follow the code from M81.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.13.d.1
Osteoporosis with current pathological fracture (M80)

Category M80, Osteoporosis with current pathological fracture, is for patients who have a current pathologic fracture at the time of an encounter. The codes under M80 identify the site of the fracture. A code from category M80, not a traumatic fracture code, should be used for any patient with known osteoporosis who suffers a fracture, even if the patient had a minor fall or trauma, if that fall or trauma would not usually break a normal, healthy bone.

— ICD-10-CM Official Guidelines for Coding and Reporting, FY2026, Section I.C.13.d.2

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

Related Codes

Search all 70,000+ ICD-10-CM codes →
Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

Get HCC Mappings, Clinical Summaries, and More

Access premium features including HCC risk adjustment, FDA drug indications, AI coding assistant, and comprehensive clinical context.

Start Free Trial