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ICD-10 Guide
ICD-10 CodesM61.169

M61.169

Billable

Myositis ossificans progressiva, unspecified lower leg

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

Code Description

ICD-10 M61.169 is a billable code used to indicate a diagnosis of myositis ossificans progressiva, unspecified lower leg.

Key Diagnostic Point:

Myositis ossificans progressiva (MOP) is a rare genetic disorder characterized by the abnormal formation of bone in muscles and connective tissues. This condition typically manifests in early childhood and progresses over time, leading to significant muscle weakness and restricted mobility. In the case of unspecified lower leg involvement, the ossification occurs in the muscles of the lower leg, which can severely impact a patient's ability to walk and perform daily activities. The condition is caused by mutations in the ACVR1 gene, which plays a crucial role in bone growth and development. Patients may experience episodes of swelling, pain, and stiffness in the affected muscles, followed by the gradual development of bone tissue in these areas. Diagnosis is often confirmed through imaging studies, such as X-rays or MRI, which reveal the presence of heterotopic ossification. Management of MOP focuses on symptomatic relief, physical therapy, and avoiding trauma to the affected areas, as injury can exacerbate ossification. Due to the progressive nature of the disease, ongoing monitoring and supportive care are essential to maintain function and quality of life.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Rarity of the condition makes it less familiar to coders.
  • Specificity required in documentation to differentiate from other myositis conditions.
  • Potential for misclassification with other musculoskeletal disorders.
  • Need for comprehensive patient history to establish the diagnosis accurately.

Audit Risk Factors

  • Inadequate documentation of clinical findings.
  • Failure to specify the affected muscle group.
  • Misinterpretation of imaging results.
  • Lack of genetic testing documentation.

Specialty Focus

Medical Specialties

Rheumatology

Documentation Requirements

Detailed clinical notes including patient history, physical examination findings, and imaging results.

Common Clinical Scenarios

Patients presenting with muscle pain and swelling, followed by restricted mobility.

Billing Considerations

Ensure genetic testing results are included in documentation to support diagnosis.

Orthopedics

Documentation Requirements

Surgical notes if applicable, imaging studies, and rehabilitation plans.

Common Clinical Scenarios

Management of complications related to ossification, such as joint stiffness.

Billing Considerations

Document any surgical interventions or physical therapy referrals.

Coding Guidelines

Inclusion Criteria

Use M61.169 When
  • Follow official ICD
  • 10 coding guidelines, ensuring that the code is used only when the condition is confirmed and documented
  • Include any relevant clinical findings and imaging results to support the diagnosis

Exclusion Criteria

Do NOT use M61.169 When
  • Exclude conditions that do not meet the criteria for myositis ossificans progressiva

Related ICD-10 Codes

Related CPT Codes

97001CPT Code

Physical therapy evaluation

Clinical Scenario

Used for initial assessment of mobility and function in patients with myositis ossificans progressiva.

Documentation Requirements

Detailed evaluation notes including range of motion and functional limitations.

Specialty Considerations

Physical therapists should document specific interventions and patient responses.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 allows for more specific coding of myositis ossificans progressiva, improving the accuracy of data collection and reimbursement processes. This specificity aids in better understanding the condition's prevalence and management.

ICD-9 vs ICD-10

The transition to ICD-10 allows for more specific coding of myositis ossificans progressiva, improving the accuracy of data collection and reimbursement processes. This specificity aids in better understanding the condition's prevalence and management.

Reimbursement & Billing Impact

reimbursement processes. This specificity aids in better understanding the condition's prevalence and management.

Resources

Clinical References

  • •
    Myositis Association

Coding & Billing References

  • •
    Myositis Association

Frequently Asked Questions

What is myositis ossificans progressiva?

Myositis ossificans progressiva is a rare genetic disorder characterized by the abnormal formation of bone in muscles and connective tissues, leading to progressive disability.

How is myositis ossificans progressiva diagnosed?

Diagnosis is based on clinical evaluation, imaging studies showing heterotopic ossification, and genetic testing for ACVR1 mutations.