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ICD-10 Guide
ICD-10 CodesM66.362

M66.362

Billable

Spontaneous rupture of flexor tendons, left lower leg

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

Code Description

ICD-10 M66.362 is a billable code used to indicate a diagnosis of spontaneous rupture of flexor tendons, left lower leg.

Key Diagnostic Point:

Spontaneous rupture of flexor tendons in the left lower leg is a condition characterized by the unexpected tearing of the flexor tendons, which are responsible for bending the toes and foot. This injury can occur without any apparent trauma or excessive force, often seen in individuals with underlying conditions such as tenosynovitis or degenerative tendon changes. The flexor tendons are encased in a synovial sheath that can become inflamed, leading to tenosynovitis, which may weaken the tendon structure over time. Symptoms typically include sudden pain, swelling, and loss of function in the affected area. Diagnosis is often confirmed through physical examination and imaging studies, such as ultrasound or MRI, which can visualize tendon integrity. Treatment may involve conservative management, such as rest and immobilization, or surgical intervention to repair the ruptured tendon, depending on the severity of the injury and the patient's overall health status. Accurate coding is essential for proper reimbursement and tracking of treatment outcomes.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between spontaneous and traumatic ruptures
  • Identifying the specific tendon involved
  • Documenting associated conditions like tenosynovitis
  • Understanding the implications of surgical versus conservative treatment

Audit Risk Factors

  • Inadequate documentation of the spontaneous nature of the rupture
  • Failure to specify the tendon involved
  • Lack of imaging studies to support the diagnosis
  • Inconsistent documentation of associated conditions

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed notes on the mechanism of injury, imaging results, and treatment plan.

Common Clinical Scenarios

Patients presenting with sudden onset pain in the lower leg, often after minimal or no trauma.

Billing Considerations

Ensure clarity on whether the rupture is spontaneous or due to an underlying condition.

Physical Medicine and Rehabilitation

Documentation Requirements

Comprehensive assessment of functional limitations and rehabilitation goals.

Common Clinical Scenarios

Patients recovering from tendon repair surgery or those with chronic pain due to tendon issues.

Billing Considerations

Document the patient's functional status and response to therapy.

Coding Guidelines

Inclusion Criteria

Use M66.362 When
  • Follow official ICD
  • 10 coding guidelines, ensuring accurate documentation of the spontaneous nature of the rupture and the specific tendon involved

Exclusion Criteria

Do NOT use M66.362 When
  • Exclude codes for traumatic ruptures unless specified

Related ICD-10 Codes

Related CPT Codes

26300CPT Code

Repair of flexor tendon

Clinical Scenario

Used when a patient undergoes surgical repair of a ruptured flexor tendon.

Documentation Requirements

Operative report detailing the procedure and findings.

Specialty Considerations

Orthopedic surgeons must document the specific tendon repaired.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of tendon injuries, improving the accuracy of data collection and reimbursement processes. M66.362 provides a clear distinction between spontaneous and traumatic ruptures, which is crucial for treatment planning and outcomes tracking.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of tendon injuries, improving the accuracy of data collection and reimbursement processes. M66.362 provides a clear distinction between spontaneous and traumatic ruptures, which is crucial for treatment planning and outcomes tracking.

Reimbursement & Billing Impact

reimbursement processes. M66.362 provides a clear distinction between spontaneous and traumatic ruptures, which is crucial for treatment planning and outcomes tracking.

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 difference between spontaneous and traumatic tendon rupture?

Spontaneous tendon rupture occurs without significant trauma, often due to underlying conditions, while traumatic rupture results from a specific injury or excessive force.