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ICD-10 Guide
ICD-10 CodesM66.331

M66.331

Billable

Spontaneous rupture of flexor tendons, right forearm

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

Code Description

ICD-10 M66.331 is a billable code used to indicate a diagnosis of spontaneous rupture of flexor tendons, right forearm.

Key Diagnostic Point:

Spontaneous rupture of flexor tendons in the right forearm is a condition characterized by the unexpected tearing of the flexor tendons, which are responsible for bending the fingers and wrist. This injury can occur without any preceding trauma or significant stress, often linked to underlying conditions such as tenosynovitis, which is inflammation of the tendon sheath. Patients may present with sudden pain, swelling, and loss of function in the affected hand. Diagnosis typically involves a thorough clinical examination and imaging studies, such as ultrasound or MRI, to confirm the rupture and assess the extent of the injury. Treatment may involve surgical intervention to repair the torn tendon, followed by rehabilitation to restore function. The prognosis depends on the severity of the rupture and the timeliness of treatment. Early intervention is crucial to prevent long-term disability and to ensure optimal recovery of hand function.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between spontaneous and traumatic ruptures
  • Understanding the relationship with underlying conditions like tenosynovitis
  • Need for precise documentation of the location and nature of the rupture
  • Potential for multiple tendon involvement requiring detailed coding

Audit Risk Factors

  • Inadequate documentation of the spontaneous nature of the rupture
  • Failure to specify the exact tendon involved
  • Lack of imaging studies to support the diagnosis
  • Misclassification of the injury as traumatic

Specialty Focus

Medical Specialties

Orthopedic Surgery

Documentation Requirements

Detailed operative notes, imaging results, and pre-operative assessments are essential.

Common Clinical Scenarios

Surgical repair of ruptured flexor tendons following spontaneous rupture.

Billing Considerations

Ensure that the surgical approach and any grafting techniques used are clearly documented.

Physical Therapy

Documentation Requirements

Progress notes detailing rehabilitation protocols and patient response to therapy.

Common Clinical Scenarios

Post-operative rehabilitation following tendon repair.

Billing Considerations

Document functional assessments and any complications during therapy.

Coding Guidelines

Inclusion Criteria

Use M66.331 When
  • According to ICD
  • 10 guidelines, M66
  • 331 should be used when the rupture is spontaneous and specifically located in the right forearm
  • Coders must ensure that the documentation supports the diagnosis and that any associated conditions are also coded appropriately

Exclusion Criteria

Do NOT use M66.331 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

26301CPT Code

Repair of flexor tendon

Clinical Scenario

Used during surgical intervention for spontaneous tendon rupture.

Documentation Requirements

Operative report detailing the procedure and any grafting used.

Specialty Considerations

Orthopedic surgeons must document the specific tendon repaired and any complications.

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. M66.331 provides a clear distinction between spontaneous and traumatic ruptures, enhancing clinical data quality.

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. M66.331 provides a clear distinction between spontaneous and traumatic ruptures, enhancing clinical data quality.

Reimbursement & Billing Impact

reimbursement and to avoid claim denials.

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 rupture of flexor tendons?

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