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v1.0.0
ICD-10 Guide
ICD-10 CodesM21.859

M21.859

Billable

Other specified acquired deformities of unspecified thigh

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

Code Description

ICD-10 M21.859 is a billable code used to indicate a diagnosis of other specified acquired deformities of unspecified thigh.

Key Diagnostic Point:

M21.859 refers to acquired deformities of the thigh that are not classified elsewhere. These deformities can arise from various causes, including trauma, surgical interventions, or underlying medical conditions that lead to structural changes in the thigh. Common examples include deformities resulting from fractures that heal improperly, post-surgical changes following orthopedic procedures, or conditions such as osteoarthritis that may alter the shape of the thigh. The unspecified nature of the code indicates that the specific type of deformity is not detailed, which can complicate treatment planning and coding accuracy. Clinicians must document the underlying cause and any associated symptoms to ensure appropriate management and coding. Treatment may involve physical therapy, corrective surgery, or the use of orthotic devices, depending on the severity and nature of the deformity. Accurate coding is essential for proper reimbursement and to reflect the complexity of the patient's condition.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Unspecified nature of the deformity complicates coding.
  • Requires detailed clinical documentation to support the diagnosis.
  • Potential overlap with other deformity codes.
  • Need for clear differentiation from congenital deformities.

Audit Risk Factors

  • Insufficient documentation of the deformity's cause.
  • Lack of specificity in clinical notes.
  • Inconsistent coding practices among providers.
  • Failure to link the deformity to a treatment plan.

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed notes on the deformity's cause, treatment plan, and any imaging studies.

Common Clinical Scenarios

Post-fracture deformities, surgical complications, or degenerative changes.

Billing Considerations

Ensure that all relevant clinical findings are documented to support the diagnosis.

Physical Therapy

Documentation Requirements

Progress notes detailing the impact of the deformity on function and response to therapy.

Common Clinical Scenarios

Rehabilitation following corrective surgery or management of deformities affecting mobility.

Billing Considerations

Document functional limitations and goals for therapy to support the need for ongoing treatment.

Coding Guidelines

Inclusion Criteria

Use M21.859 When
  • Follow official ICD
  • CM guidelines for coding and reporting
  • Ensure that the code is supported by clinical documentation that specifies the acquired nature of the deformity and any relevant treatment or management plans

Exclusion Criteria

Do NOT use M21.859 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

27447CPT Code

Osteotomy, femur

Clinical Scenario

Used in cases of acquired deformities requiring surgical correction.

Documentation Requirements

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

Specialty Considerations

Orthopedic documentation must clearly outline the need for surgery.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specificity in coding, but it has also introduced complexity with unspecified codes like M21.859. Coders must ensure thorough documentation to justify the use of this code.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specificity in coding, but it has also introduced complexity with unspecified codes like M21.859. Coders must ensure thorough documentation to justify the use of this code.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specificity in coding, but it has also introduced complexity with unspecified codes like M21.859. Coders must ensure thorough documentation to justify the use of this code.

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 documentation is needed to support the use of M21.859?

Documentation should include a detailed clinical assessment of the deformity, its cause, and any treatment plans. Imaging studies and progress notes are also essential.