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ICD-10 Guide
ICD-10 CodesM21.86

M21.86

Billable

Other specified acquired deformities of lower leg

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

Code Description

ICD-10 M21.86 is a billable code used to indicate a diagnosis of other specified acquired deformities of lower leg.

Key Diagnostic Point:

M21.86 refers to a variety of acquired deformities of the lower leg that do not fall under more specific categories. These deformities can arise from various causes, including trauma, infections, or underlying medical conditions that lead to structural changes in the leg. Common examples include deformities resulting from previous fractures that have healed improperly, conditions such as Charcot foot, or post-surgical changes. The lower leg comprises the tibia and fibula, and deformities can manifest as malalignment, shortening, or abnormal curvature. These deformities can significantly impact mobility and function, leading to pain, instability, and difficulty in weight-bearing activities. Treatment often involves a multidisciplinary approach, including orthopedic evaluation, physical therapy, and possibly surgical intervention to correct the deformity and restore function. Accurate coding is essential for appropriate management and reimbursement, as these conditions may require specialized care and interventions.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of potential underlying causes
  • Overlap with other deformity codes
  • Need for detailed clinical documentation
  • Variability in treatment approaches

Audit Risk Factors

  • Inadequate documentation of the deformity's cause
  • Failure to specify the type of deformity
  • Incorrect linkage to surgical procedures
  • Lack of follow-up documentation

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed clinical notes on the deformity's origin, treatment history, and any imaging studies.

Common Clinical Scenarios

Post-fracture deformities, Charcot foot, and post-surgical changes.

Billing Considerations

Ensure that the documentation clearly states the acquired nature of the deformity and any relevant surgical interventions.

Physical Therapy

Documentation Requirements

Therapy notes detailing functional limitations and progress in rehabilitation.

Common Clinical Scenarios

Rehabilitation following corrective surgery or management of pain and mobility issues.

Billing Considerations

Document the specific deformity and its impact on therapy goals and outcomes.

Coding Guidelines

Inclusion Criteria

Use M21.86 When
  • Follow the official ICD
  • CM coding guidelines, ensuring that the documentation supports the diagnosis
  • Include details about the acquired nature of the deformity and any relevant treatment history

Exclusion Criteria

Do NOT use M21.86 When
  • Exclude congenital deformities unless specified as acquired

Related ICD-10 Codes

Related CPT Codes

28485CPT Code

Osteotomy, tibia, or fibula

Clinical Scenario

Used for surgical correction of lower leg deformities.

Documentation Requirements

Surgical notes detailing the procedure and indication for surgery.

Specialty Considerations

Orthopedic surgeons must document the specific deformity and rationale for surgical intervention.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of acquired deformities, improving the accuracy of diagnoses and treatment tracking. M21.86 provides a distinct code for various acquired deformities, enhancing the ability to capture the complexity of these conditions.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of acquired deformities, improving the accuracy of diagnoses and treatment tracking. M21.86 provides a distinct code for various acquired deformities, enhancing the ability to capture the complexity of these conditions.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of acquired deformities, improving the accuracy of diagnoses and treatment tracking. M21.86 provides a distinct code for various acquired deformities, enhancing the ability to capture the complexity of these conditions.

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 types of deformities are included under M21.86?

M21.86 includes a variety of acquired deformities of the lower leg, such as malunions from fractures, deformities due to chronic conditions like arthritis, and post-surgical changes.