2027 ICD-10-CM Diagnosis Code S73.013APosterior subluxation of unspecified hip, initial encounter

ICD-10-CM Codes›S00–T88›S70-S79›S73

ICD-10-CM S73.013A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S73.013A is a billable ICD-10-CM diagnosis code for posterior subluxation 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 537 through 538, 963 through 965. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 12 closely related codes. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as closed posterior dislocation of hip. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Dislocations, initial encounter.

For Medicare Advantage risk adjustment, S73.013A maps to CMS-HCC Category 402 (Hip Fracture/Dislocation) under the V28 model, adding a risk factor of about 0.467 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
S73.013A
Billable Status
Yes — Valid for Submission
Code Describes
Posterior subluxation of unspecified hip, initial encounter
Short Description
Posterior subluxation of unspecified hip, initial encounter
Same as the full description in the CMS dataset.
Parent Code
S73.013
Posterior subluxation 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 CodeS73.013APosterior subluxation of unspecified hip, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S73.013A.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Medicare Risk Adjustment (HCC)Billing

S73.013A maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 402— Hip Fracture/Dislocation
Payment HCC · PY 2027 one of 729 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.467
community, non-dual, aged · ranges 0.089–0.570 across segments
Hierarchy
Top of its hierarchy
HCC 402 is not superseded by any other condition category
Prior Model (CMS-HCC V24)
HCC 170
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 170 · ESRD (V21): HCC 170 · ESRD (V24): HCC 170
ESRD V21 weights: 0.050 dialysis, 0.000–0.350 functioning graft · ESRD V24 weights: 0.063 dialysis, 0.000–0.430 functioning graft
Part D (RxHCC)
Not mapped
S73.013A does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Closed posterior dislocation of hip
  • Closed traumatic dislocation hip joint, posterior
  • Closed traumatic subluxation hip joint
  • Closed traumatic subluxation hip joint, posterior
  • Open dislocation of hip
  • Open traumatic dislocation hip joint, posterior
  • Open traumatic subluxation hip joint
  • Open traumatic subluxation hip joint, posterior
  • Posterior traumatic dislocation of hip

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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to S73.013A: its own notes plus those printed at S73.0, S73, block S70-S79, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From S73 Dislocation and sprain of joint and ligaments of hip applies to 126 codes
  • avulsion of joint or ligament of hip
  • laceration of cartilage, joint or ligament of hip
  • sprain of cartilage, joint or ligament of hip
  • traumatic hemarthrosis of joint or ligament of hip
  • traumatic rupture of joint or ligament of hip
  • traumatic subluxation of joint or ligament of hip
  • traumatic tear of joint or ligament of hip

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From S73.0 Subluxation and dislocation of hip applies to 90 codes
From S73 Dislocation and sprain of joint and ligaments of hip applies to 126 codes
  • strain of muscle, fascia and tendon of hip and thigh (S76.-)
From Block S70-S79 Injuries to the hip and thigh applies to 3,546 codes
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From S73 Dislocation and sprain of joint and ligaments of hip applies to 126 codes
  • any associated open wound

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From S73 Dislocation and sprain of joint and ligaments of hip applies to 126 codes
  • The appropriate 7th character is to be added to each code from category S73
Values for category S73 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name S73.013A, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming S73.013A: its condition is not part of those codes, and both may be reported when the patient has both.

  • S33 Dislocation and sprain of joints and ligaments of lumbar spine and pelvis
    dislocation and sprain of joints and ligaments of hip (S73.-) names S73.-, which includes this code

Clinical ClassificationClinical

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

CCSR INJ007
Dislocations, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Dislocations

Dislocations are joint injuries that force the ends of your bones out of position. The cause is often a fall or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, elbows and jaw. You can also dislocate your finger and toe joints.

Read the full article at MedlinePlus

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

Convert S73.013A to ICD-9-CMHistory

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

ICD-9-CM
835.01 Posterior disloc hip-cl
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About S73.013AOverview

What is the ICD-10 code for posterior subluxation of unspecified hip, initial encounter?

The ICD-10-CM code for posterior subluxation of unspecified hip, initial encounter is S73.013A (sometimes written as S73013A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is S73.013A (Posterior subluxation of unspecified hip) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report posterior subluxation of unspecified hip, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in S73.013A mean?

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

What MS-DRG does S73.013A group to?

When posterior subluxation of unspecified hip, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 964, 965, 537, 538, 963, with relative weights from 0.7118 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S73.013A a CC or MCC?

CMS lists S73.013A as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 12 closely related codes in its exclusion list.

What HCC is S73.013A?

S73.013A (posterior subluxation of unspecified hip, initial encounter) maps to CMS-HCC Category 402 (Hip Fracture/Dislocation), commonly written as HCC 402, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 170 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.

Does S73.013A risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, S73.013A adds a risk adjustment factor of about 0.467 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.089 to 0.570 depending on the payment segment). HCC 402 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 402 category page.