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ICD-10 Guide
ICD-10 CodesM21.371

M21.371

Billable

Foot drop, right foot

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

Code Description

ICD-10 M21.371 is a billable code used to indicate a diagnosis of foot drop, right foot.

Key Diagnostic Point:

Foot drop, also known as drop foot, is a condition characterized by the inability to lift the front part of the foot, leading to difficulty in walking. This condition can be caused by various factors, including neurological disorders, muscular dystrophies, or injuries to the peroneal nerve. In the case of M21.371, the foot drop specifically affects the right foot. Patients may exhibit a steppage gait, where they lift their knee higher than normal to avoid dragging the foot on the ground. This can lead to an increased risk of falls and other complications. Acquired deformities such as foot drop can result from conditions like stroke, multiple sclerosis, or trauma. The management of foot drop may involve physical therapy, the use of ankle-foot orthoses (AFOs), or surgical interventions to correct the underlying cause. Understanding the etiology and appropriate treatment options is crucial for effective management and rehabilitation of patients with this condition.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between acquired and congenital causes of foot drop
  • Understanding the specific neurological or muscular conditions leading to foot drop
  • Identifying associated conditions that may complicate coding
  • Documenting the severity and impact on mobility

Audit Risk Factors

  • Inadequate documentation of the underlying cause of foot drop
  • Failure to specify the affected side
  • Incorrect linkage of foot drop to unrelated conditions
  • Lack of evidence for the necessity of corrective procedures

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, including motor function assessments and diagnostic imaging results.

Common Clinical Scenarios

Patients presenting with foot drop following a stroke or traumatic brain injury.

Billing Considerations

Ensure documentation reflects the neurological basis of the foot drop and any associated deficits.

Orthopedics

Documentation Requirements

Surgical notes, pre-operative assessments, and post-operative follow-up documentation.

Common Clinical Scenarios

Patients undergoing surgical correction for foot drop due to peroneal nerve injury.

Billing Considerations

Document the rationale for surgical intervention and any pre-existing conditions that may affect recovery.

Coding Guidelines

Inclusion Criteria

Use M21.371 When
  • According to ICD
  • 10 guidelines, M21
  • 371 should be used when the foot drop is specifically affecting the right foot
  • Coders must ensure that the documentation supports the diagnosis and includes any relevant underlying conditions

Exclusion Criteria

Do NOT use M21.371 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

29530CPT Code

Application of a lower extremity orthosis

Clinical Scenario

Used when fitting a patient with an AFO for foot drop management.

Documentation Requirements

Document the patient's condition, the type of orthosis applied, and the rationale for its use.

Specialty Considerations

Orthopedic specialists should ensure that the orthotic fitting is tailored to the patient's specific needs.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of conditions like foot drop, improving the accuracy of diagnoses and treatment tracking. M21.371 provides clarity on the affected side, which is crucial for treatment planning and reimbursement.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of conditions like foot drop, improving the accuracy of diagnoses and treatment tracking. M21.371 provides clarity on the affected side, which is crucial for treatment planning and reimbursement.

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 primary cause of foot drop?

Foot drop is primarily caused by weakness or paralysis of the muscles that lift the foot, often due to peroneal nerve injury or neurological conditions such as stroke or multiple sclerosis.