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ICD-10 Guide
ICD-10 CodesM21.861

M21.861

Billable

Other specified acquired deformities of right lower leg

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

Code Description

ICD-10 M21.861 is a billable code used to indicate a diagnosis of other specified acquired deformities of right lower leg.

Key Diagnostic Point:

M21.861 refers to acquired deformities of the right lower leg that are not classified elsewhere. These deformities can arise from various causes, including trauma, surgery, or underlying medical conditions that lead to structural changes in the bones, joints, or soft tissues of the leg. Common examples include post-traumatic deformities following fractures, surgical alterations due to previous interventions, or conditions such as Charcot foot or post-polio syndrome. The acquired deformities may manifest as malalignment, shortening, or abnormal curvature of the leg, which can significantly impact mobility and function. 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 deformities can lead to complications if left untreated.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of underlying causes leading to deformities
  • Need for precise documentation of the deformity type and cause
  • Potential for co-existing conditions that complicate coding
  • Variability in treatment approaches and outcomes

Audit Risk Factors

  • Inadequate documentation of the deformity's cause
  • Failure to specify the laterality of the deformity
  • Misclassification of acquired deformities as congenital
  • Lack of supporting clinical evidence for the diagnosis

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed clinical notes describing the deformity, its cause, and treatment plan.

Common Clinical Scenarios

Post-fracture deformities, surgical corrections, and degenerative changes.

Billing Considerations

Ensure accurate laterality and specify the type of deformity for correct coding.

Physical Medicine and Rehabilitation

Documentation Requirements

Functional assessments and treatment plans addressing mobility and rehabilitation.

Common Clinical Scenarios

Rehabilitation following orthopedic surgery or trauma.

Billing Considerations

Document functional limitations and the impact of the deformity on daily activities.

Coding Guidelines

Inclusion Criteria

Use M21.861 When
  • According to ICD
  • 10 guidelines, M21
  • 861 should be used when the deformity is acquired and not due to congenital factors
  • Documentation must clearly indicate the cause and nature of the deformity

Exclusion Criteria

Do NOT use M21.861 When
  • Exclusion criteria include congenital deformities and those resulting from systemic diseases

Related ICD-10 Codes

Related CPT Codes

28485CPT Code

Osteotomy, tibia, for correction of deformity

Clinical Scenario

Used in cases where surgical correction of the acquired deformity is necessary.

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 diagnosis and treatment tracking. M21.861 provides a clear classification for acquired deformities of the right lower leg, facilitating better patient management and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of acquired deformities, improving the accuracy of diagnosis and treatment tracking. M21.861 provides a clear classification for acquired deformities of the right lower leg, facilitating better patient management and reimbursement processes.

Reimbursement & Billing Impact

reimbursement processes.

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 conditions are classified under M21.861?

M21.861 includes various acquired deformities of the right lower leg, such as post-traumatic deformities, surgical deformities, and those resulting from chronic conditions. It does not include congenital deformities or those classified under other specific codes.