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ICD-10 Guide
ICD-10 CodesM21.27

M21.27

Billable

Flexion deformity, ankle and toes

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/17/2025

Code Description

ICD-10 M21.27 is a billable code used to indicate a diagnosis of flexion deformity, ankle and toes.

Key Diagnostic Point:

Flexion deformity of the ankle and toes is characterized by an abnormal bending of the joints, leading to a fixed position that can significantly impair mobility and function. This condition is often acquired due to various factors such as trauma, neurological disorders, or chronic inflammatory diseases. Patients may present with difficulty in walking, wearing shoes, or performing daily activities due to pain and limited range of motion. The deformity can affect one or multiple toes, commonly resulting in conditions like hammertoe or mallet toe, where the toe is bent at the middle joint. In severe cases, surgical intervention may be necessary to correct the deformity and restore function. Corrective procedures may include tendon lengthening, joint fusion, or osteotomy, depending on the severity and underlying cause of the deformity. Accurate diagnosis and coding are essential for appropriate treatment planning and reimbursement.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between acquired and congenital deformities
  • Identifying the specific joints affected
  • Documenting the severity and impact on function
  • Understanding associated conditions like hallux valgus

Audit Risk Factors

  • Inadequate documentation of the deformity's impact on function
  • Failure to specify the type of flexion deformity
  • Lack of supporting evidence for surgical procedures
  • Misclassification of congenital vs. acquired deformities

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed clinical notes on the type of deformity, associated symptoms, and treatment plan.

Common Clinical Scenarios

Patients presenting with pain and functional limitations due to flexion deformities.

Billing Considerations

Ensure to document any prior treatments or interventions that may affect the current condition.

Podiatry

Documentation Requirements

Foot examination findings, including range of motion and alignment assessments.

Common Clinical Scenarios

Patients with foot pain related to hammertoe or other toe deformities.

Billing Considerations

Document any conservative treatments attempted before surgical options are considered.

Coding Guidelines

Inclusion Criteria

Use M21.27 When
  • According to ICD
  • 10 guidelines, M21
  • 27 should be used when the flexion deformity is acquired and documented as such
  • Coders must ensure that the documentation supports the diagnosis and reflects the specific joints involved

Exclusion Criteria

Do NOT use M21.27 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

28285CPT Code

Correction of hammertoe

Clinical Scenario

Used when surgical intervention is required for a flexion deformity of the toe.

Documentation Requirements

Operative report detailing the procedure and indication for surgery.

Specialty Considerations

Orthopedic or podiatric specialists should document the rationale for surgery.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of flexion deformities, improving the accuracy of diagnosis and treatment planning. M21.27 provides a clear distinction between acquired and congenital conditions, which is crucial for appropriate management.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of flexion deformities, improving the accuracy of diagnosis and treatment planning. M21.27 provides a clear distinction between acquired and congenital conditions, which is crucial for appropriate management.

Reimbursement & Billing Impact

reimbursement.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What is the primary cause of flexion deformity in the ankle and toes?

Flexion deformities can be caused by various factors, including trauma, neurological conditions, muscle imbalances, and chronic inflammatory diseases. Identifying the underlying cause is crucial for effective treatment.