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ICD-10 Guide
ICD-10 CodesM66.329

M66.329

Billable

Spontaneous rupture of flexor tendons, unspecified upper arm

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

Code Description

ICD-10 M66.329 is a billable code used to indicate a diagnosis of spontaneous rupture of flexor tendons, unspecified upper arm.

Key Diagnostic Point:

Spontaneous rupture of flexor tendons in the upper arm 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 apparent trauma or overuse, often linked to underlying conditions such as tenosynovitis, which is inflammation of the tendon sheath. The rupture may lead to significant functional impairment, pain, and swelling in the affected area. Patients may present with an inability to flex the fingers or wrist, and diagnostic imaging such as ultrasound or MRI may be utilized to confirm the diagnosis. Treatment typically involves surgical intervention to repair the ruptured tendon, followed by rehabilitation to restore function. The condition is more prevalent in individuals with pre-existing inflammatory conditions or those engaged in repetitive activities that stress the tendons. Accurate coding is essential for proper treatment reimbursement and tracking of outcomes.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in clinical presentation and severity of tendon rupture
  • Need for precise documentation of the spontaneous nature of the rupture
  • Differentiation from traumatic tendon injuries
  • Potential for co-existing conditions such as tenosynovitis

Audit Risk Factors

  • Inadequate documentation of the spontaneous nature of the rupture
  • Failure to document co-existing conditions like tenosynovitis
  • Lack of clarity in operative reports regarding the repair technique
  • Inconsistent coding of related diagnoses or procedures

Specialty Focus

Medical Specialties

Orthopedic Surgery

Documentation Requirements

Detailed operative notes, pre-operative assessments, and post-operative follow-ups are essential.

Common Clinical Scenarios

Patients presenting with acute pain and loss of function in the upper arm, often after repetitive use or with underlying inflammatory conditions.

Billing Considerations

Ensure that the documentation clearly states the spontaneous nature of the rupture and any associated conditions.

Physical Medicine and Rehabilitation

Documentation Requirements

Comprehensive rehabilitation plans and progress notes detailing functional assessments.

Common Clinical Scenarios

Patients recovering from tendon repair surgery requiring rehabilitation to regain strength and mobility.

Billing Considerations

Document the patient's functional limitations and progress towards recovery to support coding for therapy services.

Coding Guidelines

Inclusion Criteria

Use M66.329 When
  • Follow the official ICD
  • CM coding guidelines, ensuring that the documentation supports the diagnosis of spontaneous rupture without trauma
  • Include any relevant co
  • existing conditions and specify the location of the rupture

Exclusion Criteria

Do NOT use M66.329 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

26301CPT Code

Repair of flexor tendon

Clinical Scenario

Used when performing surgical repair of a ruptured flexor tendon.

Documentation Requirements

Operative report detailing the procedure, including the tendon involved and repair technique.

Specialty Considerations

Orthopedic surgeons must document the specifics of the tendon repair to ensure accurate coding.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of spontaneous tendon ruptures, improving the accuracy of data collection and reimbursement processes. This specificity helps in tracking outcomes and understanding the epidemiology of tendon injuries.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of spontaneous tendon ruptures, improving the accuracy of data collection and reimbursement processes. This specificity helps in tracking outcomes and understanding the epidemiology of tendon injuries.

Reimbursement & Billing Impact

reimbursement processes. This specificity helps in tracking outcomes and understanding the epidemiology of tendon injuries.

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 are the common causes of spontaneous rupture of flexor tendons?

Common causes include underlying inflammatory conditions such as tenosynovitis, degenerative changes in the tendon, and repetitive stress on the tendons without prior trauma.