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ICD-10 Guide
ICD-10 CodesChapter 13: Diseases of the musculoskeletal systemM23

M23

Billable

Internal derangement of knee

Chapter 13:Diseases of the musculoskeletal system

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

Code Description

ICD-10 M23 is a billable code used to indicate a diagnosis of internal derangement of knee.

Key Diagnostic Point:

Internal derangement of the knee refers to a variety of conditions that affect the knee joint's internal structures, including ligaments, menisci, and cartilage. Common causes include acute injuries, such as tears of the meniscus or ligaments, and chronic conditions resulting from repetitive stress or degeneration. Meniscal tears are particularly prevalent and can occur in various forms, including horizontal, vertical, and complex tears. Ligament injuries, such as anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) tears, can also lead to instability and pain. Symptoms typically include swelling, pain, limited range of motion, and a sensation of locking or giving way in the knee. Diagnosis often involves a combination of physical examination, imaging studies like MRI, and sometimes arthroscopy for direct visualization and treatment. Treatment options may include conservative management, such as physical therapy and bracing, or surgical interventions, including arthroscopic repair or reconstruction of damaged structures. 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

  • Variety of potential underlying causes (meniscal tears, ligament injuries)
  • Need for precise documentation of injury type and location
  • Differentiation between acute and chronic conditions
  • Potential for co-existing conditions affecting the knee

Audit Risk Factors

  • Inadequate documentation of the specific type of internal derangement
  • Failure to document the mechanism of injury
  • Lack of imaging studies to support diagnosis
  • Inconsistent coding of co-existing knee conditions

Specialty Focus

Medical Specialties

Orthopedic Surgery

Documentation Requirements

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

Common Clinical Scenarios

Meniscal repair, ACL reconstruction, and treatment of knee osteoarthritis.

Billing Considerations

Ensure that all surgical interventions are documented with specific details regarding the procedure performed.

Physical Medicine and Rehabilitation

Documentation Requirements

Comprehensive evaluations, treatment plans, and progress notes are necessary.

Common Clinical Scenarios

Rehabilitation following knee surgery, management of chronic knee pain.

Billing Considerations

Document functional limitations and response to therapy to support coding.

Coding Guidelines

Inclusion Criteria

Use M23 When
  • Follow official ICD
  • CM coding guidelines, ensuring accurate documentation of the specific type of internal derangement
  • Include details about the mechanism of injury and any associated conditions

Exclusion Criteria

Do NOT use M23 When
  • Exclude conditions that do not fit the criteria for internal derangement

Related CPT Codes

29881CPT Code

Arthroscopy, knee, diagnostic, with or without synovial biopsy

Clinical Scenario

Used when performing a diagnostic arthroscopy for internal derangement.

Documentation Requirements

Document the findings and any procedures performed during the arthroscopy.

Specialty Considerations

Orthopedic surgeons should ensure detailed operative notes are provided.

29882CPT Code

Arthroscopy, knee, surgical, with meniscectomy

Clinical Scenario

Used when a meniscal tear is surgically repaired.

Documentation Requirements

Document the type of meniscal tear and the surgical technique used.

Specialty Considerations

Orthopedic documentation must include pre-operative assessments and post-operative care plans.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of knee injuries, improving the granularity of data for treatment and outcomes. M23 provides a more detailed classification than previous ICD-9 codes, facilitating better tracking of treatment efficacy and resource allocation.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of knee injuries, improving the granularity of data for treatment and outcomes. M23 provides a more detailed classification than previous ICD-9 codes, facilitating better tracking of treatment efficacy and resource allocation.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of knee injuries, improving the granularity of data for treatment and outcomes. M23 provides a more detailed classification than previous ICD-9 codes, facilitating better tracking of treatment efficacy and resource allocation.

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 M23.1 and M23.2?

M23.1 refers specifically to a medial meniscal tear, while M23.2 refers to a lateral meniscal tear. Accurate coding requires specifying the location of the tear.

When should I use M23.9?

M23.9 should be used when the specific type of internal derangement is not documented or when the details are insufficient to assign a more specific code.