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ICD-10 Guide
ICD-10 CodesM21.621

M21.621

Billable

Bunionette of right foot

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

Code Description

ICD-10 M21.621 is a billable code used to indicate a diagnosis of bunionette of right foot.

Key Diagnostic Point:

A bunionette, also known as a tailor's bunion, is a bony prominence that occurs at the base of the fifth toe, resulting from the misalignment of the toe joint. This acquired deformity is characterized by lateral deviation of the fifth toe, leading to pain, swelling, and discomfort, particularly when wearing tight shoes. The condition is often exacerbated by footwear that does not accommodate the natural shape of the foot, leading to increased pressure on the fifth metatarsal head. Over time, this misalignment can cause inflammation of the surrounding soft tissues, resulting in bursitis. Patients may present with symptoms such as localized pain, redness, and tenderness at the site of the bunionette. Diagnosis is typically made through clinical examination, and imaging studies may be utilized to assess the degree of deformity and rule out other conditions. Treatment options range from conservative measures, such as orthotic devices and footwear modifications, to surgical interventions aimed at realigning the toe and alleviating pain. Corrective procedures may include osteotomy of the fifth metatarsal or excision of the bony prominence, depending on the severity of the deformity and the patient's symptoms.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between bunionette and other toe deformities
  • Understanding the specific anatomical location of the bunionette
  • Documenting associated symptoms and severity accurately
  • Identifying appropriate treatment options and their documentation

Audit Risk Factors

  • Inadequate documentation of symptoms and clinical findings
  • Failure to specify the laterality of the condition
  • Misclassification of the condition as hallux valgus
  • Lack of documentation for conservative treatment measures prior to surgery

Specialty Focus

Medical Specialties

Podiatry

Documentation Requirements

Detailed clinical notes including patient history, physical examination findings, and treatment plans.

Common Clinical Scenarios

Patients presenting with foot pain, deformities, or complications from bunionettes.

Billing Considerations

Ensure clear documentation of the deformity's impact on the patient's daily activities and footwear choices.

Orthopedics

Documentation Requirements

Comprehensive assessment of foot structure, imaging results, and surgical recommendations.

Common Clinical Scenarios

Patients requiring surgical intervention for bunionette correction or those with recurrent symptoms.

Billing Considerations

Document the rationale for surgical intervention and any pre-operative assessments performed.

Coding Guidelines

Inclusion Criteria

Use M21.621 When
  • According to ICD
  • 10 guidelines, M21
  • 621 should be used when the bunionette is specifically located on the right foot
  • Coders must ensure that the documentation supports the diagnosis and that the condition is not a result of congenital factors

Exclusion Criteria

Do NOT use M21.621 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

28296CPT Code

Osteotomy, fifth metatarsal

Clinical Scenario

Used for surgical correction of bunionette deformity.

Documentation Requirements

Pre-operative assessment, surgical notes, and post-operative follow-up.

Specialty Considerations

Podiatrists and orthopedic surgeons should document the rationale for surgery and any complications.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of foot deformities, including bunionettes, improving the accuracy of patient records and facilitating better treatment planning.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of foot deformities, including bunionettes, improving the accuracy of patient records and facilitating better treatment planning.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of foot deformities, including bunionettes, improving the accuracy of patient records and facilitating better treatment planning.

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 difference between a bunion and a bunionette?

A bunion (hallux valgus) occurs at the base of the big toe, while a bunionette (tailor's bunion) occurs at the base of the fifth toe, leading to different symptoms and treatment approaches.