2027 ICD-10-CM Diagnosis Code M22.42Chondromalacia patellae, left knee
ICD-10-CM Codes›M00–M99›M20-M25›M22
- Billable — Valid for Submission
- Chronic Condition
M22.42 is a billable ICD-10-CM diagnosis code for chondromalacia patellae, left knee. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 562 through 563. Coders also document this condition as chondromalacia of bilateral patellas. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chondromalacia of bilateral patellas
- Chondromalacia of joint of left knee
- Chondromalacia of joint of right knee
- Chondromalacia of left patella
- Chondromalacia of patella
- Chondromalacia of right patella
- Degenerative disorder of articular cartilage of left knee
- Degenerative disorder of articular cartilage of right knee
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M22.42: its own notes plus those printed at M22, block M00-M25, block M20-M25, and Chapter 13. 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.
- Disorders affecting predominantly peripheral (limb) joints
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.
- 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)
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
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name M22.42, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Chondromalacia Patellae
a degeneration of the articular cartilage of the patella, caused by a decrease in sulfated mucopolysaccharides in the ground substance. when accompanied by pain, it is sometimes considered part of or confused with patellofemoral pain syndrome.
Patient EducationClinical
Knee Injuries and Disorders
Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M22.42 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M22.42Overview
What is the ICD-10 code for chondromalacia patellae, left knee?
The ICD-10-CM code for chondromalacia patellae, left knee is M22.42 (sometimes written as M2242). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M22.42 (Chondromalacia patellae) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chondromalacia patellae, left knee on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M22.42 group to?
When chondromalacia patellae, left knee is the principal diagnosis on an inpatient stay, it groups to MS-DRG 563, 562, with relative weights from 0.8982 to 1.3981 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M22.42?
Under the General Equivalence Mappings, chondromalacia patellae, left knee converts to ICD-9-CM 717.7 (chondromalacia patellae). The mapping is approximate, so confirm the match fits the documentation.
