M21.959
✓ BillableUnspecified acquired deformity of unspecified thigh
Diseases of the musculoskeletal system and connective tissue (M00-M99)
❌ Excludes1
inheritedRules inherited from parent codes in the hierarchy.
- • acquired absence of limb (Z89.-)
- • congenital absence of limbs (Q71-Q73)
- • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)
⚠️ Excludes2
inheritedRules inherited from parent codes.
- • acquired deformities of fingers or toes (M20.-)
- • coxa plana (M91.2)
Clinical Description
ICD-10-CM code M21.959 represents unspecified acquired deformity of unspecified thigh. This code falls under the Diseases of the musculoskeletal system and connective tissue (M00-M99) classification. It is a billable/specific code valid for HIPAA-covered transactions as of October 1, 2025 (FY2026). This code can be used to indicate a diagnosis for reimbursement purposes on insurance claims.
This is a 7-character code at the 6th level of specificity. This is the most specific code available in this subcategory. Coders should note that M21.959 has 3 Excludes1 restriction(s) — codes that cannot be reported together on the same claim.
Frequently Asked Questions
What is ICD-10 code M21.959?
ICD-10-CM code M21.959 is "Unspecified acquired deformity of unspecified thigh". It belongs to the category: Diseases of the musculoskeletal system and connective tissue (M00-M99).
Is M21.959 a billable ICD-10 code?
Yes, M21.959 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
What codes are excluded with M21.959?
M21.959 has 3 Excludes1 rule(s). These codes are mutually exclusive and cannot be coded together on the same claim.
Can M21.959 be coded with other codes?
M21.959 has 2 Excludes2 note(s). These conditions can be coded together if both are documented in the patient record.
Related Codes in M21.95
Other codes in the same category that may be relevant for differential coding:
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Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)