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v1.0.0
ICD-10 Guide
ICD-10 CodesM21.279

M21.279

Billable

Flexion deformity, unspecified ankle and toes

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

Code Description

ICD-10 M21.279 is a billable code used to indicate a diagnosis of flexion deformity, unspecified ankle and toes.

Key Diagnostic Point:

Flexion deformity of the ankle and toes refers to a condition where there is an abnormal bending or flexing of the joints, leading to a reduced range of motion and potential functional impairment. This condition can arise from various acquired factors, including trauma, neurological disorders, or chronic inflammatory diseases. Patients may present with difficulty in ambulation, pain, and altered gait patterns. Commonly associated with conditions such as hallux valgus, where the big toe deviates laterally, flexion deformities can also affect the lesser toes, leading to overlapping or claw-like appearances. Treatment options may include physical therapy, orthotic devices, and in some cases, surgical interventions to correct the deformity and restore function. Accurate coding is essential for proper management and reimbursement, as these deformities can significantly impact a patient's quality of life and require multidisciplinary care.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in presentation and severity of the deformity
  • Need for detailed documentation of the underlying cause
  • Differentiation from other toe and ankle deformities
  • Potential for co-existing conditions that complicate coding

Audit Risk Factors

  • Inadequate documentation of the deformity's severity
  • Failure to specify the affected joints
  • Lack of evidence for acquired causes
  • Inconsistent coding with treatment provided

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed clinical notes describing the deformity, treatment plans, and any imaging studies.

Common Clinical Scenarios

Patients presenting with pain and deformity in the toes or ankle, often requiring surgical intervention.

Billing Considerations

Ensure that all relevant diagnostic tests and their results are documented to support the coding.

Physical Therapy

Documentation Requirements

Progress notes detailing the patient's functional status and response to therapy.

Common Clinical Scenarios

Rehabilitation of patients post-surgery or those with chronic deformities requiring conservative management.

Billing Considerations

Documenting the specific exercises and modalities used to treat the flexion deformity.

Coding Guidelines

Inclusion Criteria

Use M21.279 When
  • According to ICD
  • 10 guidelines, M21
  • 279 should be used when the flexion deformity is not specified further
  • Coders must ensure that the documentation supports the diagnosis and that any underlying conditions are also coded appropriately

Exclusion Criteria

Do NOT use M21.279 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

28285CPT Code

Correction of hallux valgus

Clinical Scenario

Used when surgical correction is performed for a patient with a flexion deformity of the big toe.

Documentation Requirements

Operative reports detailing the procedure and pre-operative assessments.

Specialty Considerations

Orthopedic surgeons must document the rationale for surgery and any pre-existing conditions.

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 ability to capture the complexity of these conditions and their treatment.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of flexion deformities, improving the ability to capture the complexity of these conditions and their treatment.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of flexion deformities, improving the ability to capture the complexity of these conditions and their treatment.

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 deformities?

Flexion deformities can arise from various acquired conditions, including trauma, arthritis, or neurological disorders that affect muscle control and joint stability.