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ICD-10-CM 2027 diagnosis code

M23.40Loose body in knee, unspecified knee

✓ Billable / specific

M23.40 is a valid, billable ICD-10-CM code for loose body in knee, unspecified knee. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M23.40

M23.40 is the ICD-10-CM diagnosis code for Loose body in knee, unspecified knee. It belongs to category M23 (internal derangement of knee), block M20-M25 (other joint disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within M23.4, choose M23.40 (unspecified knee) only when documentation doesn't support a more specific option: right knee (M23.41) and left knee (M23.42).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC, relative weight 1.4908), DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC, relative weight 0.9783) and DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC, relative weight 0.7378), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 717.6 (Loose body in knee).

Notes that apply from higher levels

Instructions written at a parent level also apply to M23.40.

› From M23 Internal derangement of knee
Excludes1
  • ankylosis (M24.66)
  • deformity of knee (M21.-)
  • osteochondritis dissecans (M93.2)
Excludes2
  • current injury - see injury of knee and lower leg (S80-S89)
  • recurrent dislocation or subluxation of joints (M24.4)
  • recurrent dislocation or subluxation of patella (M22.0-M22.1)

Broader instructions also apply from M20-M25 Other joint disorders and Chapter 13: Diseases of the musculoskeletal system and connective tissue.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 717.6Loose body in kneeapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M23.40

Is M23.40 billable?

Yes. M23.40 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M23.40 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M23.40 as a principal diagnosis.

Is M23.40 a CC or MCC?

No. M23.40 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M23.40 group to?

M23.40 is used in the MS-DRG v44.0 logic for MS-DRG 564 (Other Musculoskeletal System and Connective Tissue Diagnoses with MCC), MS-DRG 565 (Other Musculoskeletal System and Connective Tissue Diagnoses with CC) and MS-DRG 566 (Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for M23.40?

The CMS General Equivalence Mappings map M23.40 to ICD-9-CM 717.6.