2026 ICD-10-CM Diagnosis Code M24.659Ankylosis, unspecified hip

ICD-10-CM Codes›M00–M99›M20-M25›M24

ICD-10-CM M24.659
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M24.659 is a billable ICD-10-CM diagnosis code for ankylosis, unspecified hip. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 553 through 554. Coders also document this condition as ankylosis of hip joint. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.

Code Identity

ICD-10-CM Code
M24.659
Billable Status
Yes — Valid for Submission
Code Describes
Ankylosis, unspecified hip
Short Description
Ankylosis, unspecified hip
Same as the full description in the CMS dataset.
Parent Code
M24.65
Ankylosis, hip

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM24Other specific joint derangements
This CodeM24.659Ankylosis, unspecified hip

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Ankylosis of hip joint
  • Ankylosis of joint of pelvic region
  • Ankylosis of joint of pelvis and/or hip
  • Ankylosis of sacroiliac joint
  • Arthrofibrosis of joint of hip

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS007
Other specified joint disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Hip Injuries and Disorders

Your hip is the joint where your femur (thigh bone) meets your pelvis (hip bone). There are two main parts: a ball at the end of the femur, which fits in a socket in the pelvis. Your hip is known as a ball-and-socket joint. This is because you have a ball at the end of your femur, and it fits into a socket in your pelvis.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M24.659 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
718.55 Ankylosis-pelvis
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M24.659Overview

Is M24.659 (Ankylosis, hip) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report ankylosis, unspecified hip on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M24.659 group to?

When ankylosis, unspecified hip is the principal diagnosis on an inpatient stay, it groups to MS-DRG 553, 554, with relative weights from 0.8301 to 1.2963 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M24.659?

Under the General Equivalence Mappings, ankylosis, unspecified hip converts to ICD-9-CM 718.55 (ankylosis-pelvis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.