2027 ICD-10-CM Diagnosis Code M84.642KPathological fracture in other disease, left hand, subsequent encounter for fracture with nonunion
ICD-10-CM Codes›M00–M99›M80-M85›M84
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- 7th Character K — Subsequent, Nonunion
- Not Chronic
M84.642K is a billable ICD-10-CM diagnosis code for pathological fracture in other disease, left hand, subsequent encounter for fracture with nonunion. The 7th character K means subsequent encounter for fracture with nonunion. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566. 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 5,561 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Pathological fracture, subsequent encounter.
Code Identity
Code Classification
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M84.642K: its own notes plus those printed at M84.6, M84, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
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.
- traumatic fracture of bone-see fracture, by site
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
- underlying condition
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
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.
- The appropriate 7th character is to be added to each code from subcategory M84.6:
- Ainitial encounter for fracture
- Dsubsequent encounter for fracture with routine healing
- Gsubsequent encounter for fracture with delayed healing
- Ksubsequent encounter for fracture with nonunion this code
- Psubsequent encounter for fracture with malunion
- 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 M84.642K, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Fractures
A fracture is a break in a bone. Fractures are usually caused by injuries. Since they can sometimes be serious, it's important to get medical care right away if you think you have a fracture.
The full article covers:
- What is a fracture?
- What are the different types of fractures?
- What causes fractures?
- What are the symptoms of a fracture?
- How are fractures diagnosed?
- What are the treatments for fractures?
- Can fractures be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M84.642K to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M84.642KOverview
Is M84.642K (Pathological fracture in other disease, left hand) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pathological fracture in other disease, left hand, subsequent encounter for fracture with nonunion on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character K in M84.642K mean?
The final character K reports a subsequent encounter where the pathological fracture in other disease, left hand has failed to heal, called a nonunion. In this category the CMS Tabular List defines K as "subsequent encounter for fracture with nonunion".
What MS-DRG does M84.642K group to?
When pathological fracture in other disease, left hand, subsequent encounter for fracture with nonunion is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 566, 565, with relative weights from 0.7374 to 1.4909 depending on complications. Higher weights mean higher Medicare reimbursement.
Is M84.642K a CC or MCC?
CMS lists M84.642K 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 5,561 closely related codes in its exclusion list.
Can M84.642K be reported with a code from M80?
Not as a rule. The Excludes1 note at M84.6, which applies to M84.642K, lists "pathological fracture in osteoporosis (M80.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
