2026 ICD-10-CM Diagnosis Code S43.421SSprain of right rotator cuff capsule, sequela
S43.421S is a billable ICD-10-CM diagnosis code for sprain of right rotator cuff capsule, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 562 through 563. The code is exempt from POA reporting. Coders also document this condition as disorder of ligament of right shoulder joint. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.
This medical diagnosis code is frequently used in Orthopedics medical specialties to designate conditions such selected sprains rotator cuff, cruciate ligament, and ankle.
Code Identity
Code Classification
Present on Admission (POA)Billing
S43.421S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Disorder of ligament of right shoulder joint
- Disorder of ligament of right shoulder region
- Sprain of ligament of right shoulder joint
- Sprain of right rotator cuff capsule
- Sprain of shoulder
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Dislocation and sprain of joints and ligaments of shoulder girdle (S43). 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.
Patient EducationClinical
Rotator Cuff Injuries
Your rotator cuff is part of your shoulder joint. It's a group of muscles and tendons that holds the top part of your upper arm bone firmly in your shoulder socket. The rotator cuff keeps your shoulder stable when you move your arm in any direction.
The full article covers:
- What is a rotator cuff?
- What are rotator cuff injuries?
- Who is more likely to develop a rotator cuff injury?
- What are the symptoms of rotator cuff injuries?
- How are rotator cuff injuries diagnosed?
- What are the treatments for rotator cuff injuries?
- When should I see a health care provider for shoulder pain?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S43.421S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S43.421SOverview
Is S43.421S (Sprain of right rotator cuff capsule) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report sprain of right rotator cuff capsule, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in S43.421S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the sprain of right rotator cuff capsule itself has resolved, not the original event.
What MS-DRG does S43.421S group to?
When sprain of right rotator cuff capsule, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 562, 563, with relative weights from 0.8955 to 1.4248 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S43.421S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for sprain of right rotator cuff capsule, sequela on inpatient claims.
What is the ICD-9 equivalent of S43.421S?
Under the General Equivalence Mappings, sprain of right rotator cuff capsule, sequela converts to ICD-9-CM 905.7 (late effec sprain/strain). 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.
