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ICD-10 Guide
ICD-10 CodesM21.20

M21.20

Billable

Flexion deformity, unspecified site

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

Code Description

ICD-10 M21.20 is a billable code used to indicate a diagnosis of flexion deformity, unspecified site.

Key Diagnostic Point:

Flexion deformity refers to a condition where a joint is bent in a way that limits its range of motion, often resulting in a permanent or semi-permanent position. This condition can occur in various joints, including fingers and toes, and may arise from a variety of causes such as trauma, neurological disorders, or chronic inflammatory conditions. Acquired flexion deformities are particularly common in the fingers and toes, where conditions like Dupuytren's contracture or hallux valgus can lead to significant functional impairment. In hallux valgus, the big toe deviates laterally, causing the first metatarsal to protrude medially, which can lead to a flexion deformity of the toe. Corrective procedures may include surgical interventions such as osteotomy or tendon release to restore normal alignment and function. Accurate coding of flexion deformities is essential for appropriate treatment planning and reimbursement, as it reflects the complexity and impact of the condition on the patient's quality of life.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in presentation and severity of the deformity
  • Differentiation between congenital and acquired deformities
  • Need for detailed documentation of the site and extent of the deformity
  • Potential for co-existing conditions that may complicate coding

Audit Risk Factors

  • Insufficient documentation of the deformity's specifics
  • Inconsistent coding of related conditions
  • Failure to document the impact on function
  • Lack of clarity on the treatment plan

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed descriptions of the deformity, treatment plans, and outcomes.

Common Clinical Scenarios

Patients presenting with joint pain, limited mobility, or post-surgical follow-ups.

Billing Considerations

Ensure that all surgical interventions and their outcomes are documented to support the diagnosis.

Physical Medicine and Rehabilitation

Documentation Requirements

Functional assessments and treatment goals related to the deformity.

Common Clinical Scenarios

Rehabilitation following corrective surgery or management of chronic deformities.

Billing Considerations

Documenting the impact on daily activities and quality of life is crucial.

Coding Guidelines

Inclusion Criteria

Use M21.20 When
  • According to ICD
  • 10 coding guidelines, M21
  • 20 should be used when the specific site of the flexion deformity is not documented
  • Coders should ensure that the documentation supports the diagnosis and that any related conditions are also coded appropriately

Exclusion Criteria

Do NOT use M21.20 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

28296CPT Code

Osteotomy, first metatarsal

Clinical Scenario

Used in the surgical correction of hallux valgus with associated flexion deformity.

Documentation Requirements

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

Specialty Considerations

Orthopedic documentation must include the rationale for surgery and expected outcomes.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specificity in coding, which can improve the accuracy of diagnoses and treatment plans. M21.20 serves as a catch-all for flexion deformities that do not have a specified site, but coders should strive for more specific codes when available.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specificity in coding, which can improve the accuracy of diagnoses and treatment plans. M21.20 serves as a catch-all for flexion deformities that do not have a specified site, but coders should strive for more specific codes when available.

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 significance of coding M21.20?

Coding M21.20 is significant as it captures the presence of a flexion deformity that is not specified, allowing for tracking of these conditions in healthcare systems. Accurate coding is essential for treatment planning and reimbursement.