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ICD-10 Guide
ICD-10 CodesChapter 13: Diseases of the musculoskeletal systemM66

M66

Billable

Spontaneous rupture of synovium and tendon

Chapter 13:Diseases of the musculoskeletal system

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

Code Description

ICD-10 M66 is a billable code used to indicate a diagnosis of spontaneous rupture of synovium and tendon.

Key Diagnostic Point:

Spontaneous rupture of synovium and tendon refers to the unexpected tearing of the synovial membrane and associated tendons, often occurring without any preceding trauma or injury. This condition can arise due to various factors, including chronic inflammation, degenerative changes, or underlying systemic diseases such as rheumatoid arthritis or gout. The synovium, which lines the joints and tendon sheaths, plays a crucial role in joint lubrication and nutrient supply. When it ruptures, it can lead to significant pain, swelling, and impaired mobility. The rupture may also result in the release of synovial fluid into the surrounding tissues, causing further inflammation and discomfort. Clinically, patients may present with acute pain, swelling, and limited range of motion in the affected joint or tendon. Diagnosis typically involves a thorough clinical examination, imaging studies such as ultrasound or MRI, and sometimes arthroscopy. Treatment options may include conservative management with rest, ice, and anti-inflammatory medications, or surgical intervention to repair the ruptured structures, depending on the severity and location of the rupture.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating between spontaneous and traumatic ruptures
  • Identifying underlying conditions contributing to the rupture
  • Documentation of clinical findings and imaging results
  • Understanding the relationship between synovial disorders and tendon health

Audit Risk Factors

  • Inadequate documentation of the spontaneous nature of the rupture
  • Failure to document associated conditions or comorbidities
  • Lack of imaging studies to support the diagnosis
  • Inconsistent coding of related procedures or treatments

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed clinical notes, imaging results, and treatment plans must be documented to support the diagnosis.

Common Clinical Scenarios

Patients presenting with acute joint pain and swelling, often following a history of chronic joint issues.

Billing Considerations

Orthopedic surgeons should ensure that the surgical notes clearly describe the nature of the rupture and any repairs performed.

Rheumatology

Documentation Requirements

Comprehensive history of joint symptoms, laboratory results, and imaging studies to assess underlying conditions.

Common Clinical Scenarios

Patients with autoimmune disorders presenting with joint pain and swelling, potentially leading to spontaneous ruptures.

Billing Considerations

Rheumatologists should document the relationship between systemic diseases and joint health to support coding.

Coding Guidelines

Inclusion Criteria

Use M66 When
  • According to ICD
  • 10 guidelines, M66 should be used when there is clear documentation of spontaneous rupture without prior trauma
  • It is essential to include any relevant comorbidities or underlying conditions that may have contributed to the rupture

Exclusion Criteria

Do NOT use M66 When
No specific exclusions found.

Related CPT Codes

29806CPT Code

Arthroscopy, shoulder, surgical

Clinical Scenario

Used when surgical intervention is required for spontaneous rupture repair.

Documentation Requirements

Operative report detailing the procedure and findings.

Specialty Considerations

Orthopedic surgeons should ensure accurate coding of the procedure in relation to the diagnosis.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of spontaneous ruptures, improving the accuracy of data collection and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of spontaneous ruptures, improving the accuracy of data collection 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 primary cause of spontaneous rupture of synovium and tendon?

The primary causes include chronic inflammatory conditions, degenerative changes, and systemic diseases that weaken the synovial and tendon structures.