2026 ICD-10-CM Diagnosis Code S73.129AIschiocapsular ligament sprain of unspecified hip, initial encounter

ICD-10-CM Codes›S00–T88›S70-S79›S73

ICD-10-CM S73.129A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S73.129A is a billable ICD-10-CM diagnosis code for ischiocapsular ligament sprain of unspecified hip, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 537 through 538, 963 through 965. Coders also document this condition as sprain of hip. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sprains and strains, initial encounter.

Code Identity

ICD-10-CM Code
S73.129A
Billable Status
Yes — Valid for Submission
Code Describes
Ischiocapsular ligament sprain of unspecified hip, initial encounter
Short Description
Ischiocapsular ligament sprain of unsp hip, init encntr
Parent Code
S73.129
Ischiocapsular ligament sprain of unspecified hip

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS70-S79Injuries to the hip and thigh
CategoryS73Dislocation and sprain of joint and ligaments of hip
This CodeS73.129AIschiocapsular ligament sprain of unspecified hip, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Sprain of hip
  • Sprain of iliofemoral ligament

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Dislocation and sprain of joint and ligaments of hip (S73). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR INJ024
Sprains and strains, initial encounter
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 S73.129A to ICD-9-CMHistory

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

ICD-9-CM
843.1 Sprain ischiocapsular
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 S73.129AOverview

Is S73.129A (Ischiocapsular ligament sprain of unspecified hip) a billable code?

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

What does the 7th character A in S73.129A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for ischiocapsular ligament sprain of unspecified hip, such as an emergency visit or first evaluation.

What MS-DRG does S73.129A group to?

When ischiocapsular ligament sprain of unspecified hip, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 537, 538, 963, 964, 965, with relative weights from 0.7203 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S73.129A?

Under the General Equivalence Mappings, ischiocapsular ligament sprain of unspecified hip, initial encounter converts to ICD-9-CM 843.1 (sprain ischiocapsular). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.