Non-Billable / Non-Specific Code
ICD-10-CM M25.66 is the diagnosis code for Stiffness of knee, not elsewhere classified. This code falls under the section "Other joint disorders" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where M25.66 sits in the ICD-10-CM classification helps ensure proper coding:
No, M25.66 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
M25.66 is the ICD-10-CM diagnosis code for "Stiffness of knee, not elsewhere classified". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of M25.66 is M25.6 ("Stiffness of joint, not elsewhere classified"). M25.66 provides a more specific classification within this category.
M25.66 is located in Section M20-M25 — "Other joint disorders" within Chapter 13 of the ICD-10-CM Tabular List.
M25.66 has 3 sub-code(s) that provide more specific detail: M25.661, M25.662, M25.669.
Use M25.66 when the patients documented diagnosis matches "Stiffness of knee, not elsewhere classified" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Stiffness of knee, not elsewhere classified is M25.66.
No, M25.66 is non-billable. Use a more specific sub-code for primary diagnosis billing.
M25.66 is in Chapter 13 of the ICD-10-CM Tabular List.
Yes, M25.66 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.