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ICD-10 Guide
ICD-10 CodesM66.879

M66.879

Billable

Spontaneous rupture of other tendons, unspecified ankle and foot

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

Code Description

ICD-10 M66.879 is a billable code used to indicate a diagnosis of spontaneous rupture of other tendons, unspecified ankle and foot.

Key Diagnostic Point:

Spontaneous rupture of tendons in the ankle and foot can occur due to various factors, including underlying degenerative conditions, acute trauma, or chronic overuse. This condition is characterized by the sudden tearing of tendons, which may lead to significant pain, swelling, and functional impairment. Commonly affected tendons include those associated with the Achilles, peroneal, and tibialis muscles. Patients may present with acute pain, an audible 'pop' at the time of injury, and difficulty bearing weight. Diagnosis typically involves a thorough clinical examination, imaging studies such as ultrasound or MRI, and assessment of functional limitations. Treatment options vary based on the severity of the rupture and may include conservative management with rest, ice, compression, and elevation (RICE), physical therapy, or surgical intervention to repair the torn tendon. Surgical repair is often indicated for complete ruptures or when conservative measures fail to alleviate symptoms. 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

  • Variability in clinical presentation and severity of tendon ruptures
  • Need for precise documentation of the mechanism of injury
  • Differentiation from other tendon injuries and conditions
  • Potential for co-existing conditions affecting treatment and coding

Audit Risk Factors

  • Inadequate documentation of the mechanism of injury
  • Failure to specify the exact tendon involved
  • Lack of imaging studies to support diagnosis
  • Inconsistent treatment documentation

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

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

Common Clinical Scenarios

Acute tendon ruptures following sports injuries, chronic tendon degeneration leading to spontaneous rupture.

Billing Considerations

Ensure that all surgical interventions are documented, including pre-operative assessments and post-operative care.

Physical Medicine and Rehabilitation

Documentation Requirements

Comprehensive assessment of functional limitations, rehabilitation goals, and progress notes.

Common Clinical Scenarios

Patients undergoing rehabilitation post-surgery for tendon repair or those with conservative management.

Billing Considerations

Document the patient's response to therapy and any modifications to the rehabilitation plan.

Coding Guidelines

Inclusion Criteria

Use M66.879 When
  • Follow official coding guidelines for reporting tendon injuries, ensuring that the documentation supports the diagnosis
  • Include details about the specific tendon involved, the mechanism of injury, and any associated conditions

Exclusion Criteria

Do NOT use M66.879 When
  • Exclude codes for tendon ruptures that are due to trauma or other specified conditions

Related ICD-10 Codes

Related CPT Codes

27658CPT Code

Repair of ruptured tendon

Clinical Scenario

Used when surgical repair is performed for a spontaneous tendon rupture.

Documentation Requirements

Operative report detailing the procedure, findings, and post-operative care.

Specialty Considerations

Orthopedic surgeons must document the specific tendon repaired and the surgical technique used.

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 diagnoses and treatment tracking. M66.879 provides a clear designation for spontaneous ruptures, facilitating better patient management and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of tendon injuries, improving the accuracy of diagnoses and treatment tracking. M66.879 provides a clear designation for spontaneous ruptures, 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 is the difference between spontaneous and traumatic tendon rupture?

Spontaneous tendon rupture occurs without a specific traumatic event, often due to degeneration or chronic conditions, while traumatic rupture results from a specific injury or accident.