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v1.0.0
ICD-10 Guide
ICD-10 CodesM05.06

M05.06

Billable

Felty's syndrome, knee

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/12/2025

Code Description

ICD-10 M05.06 is a billable code used to indicate a diagnosis of felty's syndrome, knee.

Key Diagnostic Point:

Felty's syndrome is a rare complication of rheumatoid arthritis characterized by the triad of rheumatoid arthritis, splenomegaly, and leukopenia. In the context of the knee, patients may experience significant joint inflammation, pain, and swelling due to the autoimmune process affecting the synovial membrane. Anatomically, the knee joint comprises the femur, tibia, fibula, and patella, with ligaments and cartilage providing stability and mobility. The pathophysiology involves immune-mediated damage to the joint structures, leading to chronic inflammation and potential joint deformities. Clinically, patients may present with decreased range of motion, joint effusion, and systemic symptoms such as fatigue and malaise. The knee is often a primary site of involvement, leading to functional limitations in activities of daily living and mobility.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Requires understanding of autoimmune processes and their impact on musculoskeletal structures.
  • Involves multiple body systems (musculoskeletal and hematologic).
  • Documentation must reflect both joint-specific and systemic manifestations.
  • Differentiation from other forms of arthritis and related conditions is necessary.

Audit Risk Factors

  • Inadequate documentation of systemic symptoms and their relation to knee involvement.
  • Failure to document the severity of joint involvement.
  • Misclassification of the condition due to overlapping symptoms with other arthritic conditions.
  • Lack of clear linkage between the diagnosis and treatment provided.

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Orthopedic documentation should include imaging studies (e.g., X-rays, MRIs) to assess joint integrity, as well as functional assessments to evaluate range of motion and stability.

Common Clinical Scenarios

Patients may require surgical intervention such as arthroscopy or joint replacement due to severe joint damage.

Billing Considerations

Documentation must detail the extent of joint damage and any surgical findings.

Rheumatology

Documentation Requirements

Rheumatologic documentation should include laboratory tests for inflammatory markers (e.g., ESR, CRP) and assessments of disease activity (e.g., DAS28 score).

Common Clinical Scenarios

Management of Felty's syndrome may involve disease-modifying antirheumatic drugs (DMARDs) and biologics.

Billing Considerations

Systemic involvement must be documented, including any splenomegaly and leukopenia.

Physical Medicine

Documentation Requirements

Functional assessments should evaluate mobility, strength, and the need for assistive devices.

Common Clinical Scenarios

Rehabilitation may focus on restoring function and managing pain through physical therapy.

Billing Considerations

Documentation should reflect the impact of knee involvement on overall mobility and daily activities.

Coding Guidelines

Inclusion Criteria

Use M05.06 When
  • 10 coding guidelines require specificity in laterality (e
  • , left, right, bilateral) and severity of the condition
  • Documentation must reflect the encounter type (initial, follow
  • up, or acute exacerbation) and any relevant comorbidities

Exclusion Criteria

Do NOT use M05.06 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

20610CPT Code

Arthrocentesis, aspiration and/or injection into a major joint or bursa

Clinical Scenario

Used for knee joint effusion management in Felty's syndrome.

Documentation Requirements

Document the joint involved, the procedure performed, and the indication for the procedure.

Specialty Considerations

Orthopedic and rheumatologic considerations for joint management.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for greater specificity in coding musculoskeletal conditions, particularly those with systemic involvement like Felty's syndrome. This specificity aids in better tracking of patient outcomes and resource allocation.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for greater specificity in coding musculoskeletal conditions, particularly those with systemic involvement like Felty's syndrome. This specificity aids in better tracking of patient outcomes and resource allocation.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for greater specificity in coding musculoskeletal conditions, particularly those with systemic involvement like Felty's syndrome. This specificity aids in better tracking of patient outcomes and resource allocation.

Resources

Clinical References

  • •
    American College of Rheumatology Guidelines

Coding & Billing References

  • •
    American College of Rheumatology Guidelines

Frequently Asked Questions

What are the key symptoms of Felty's syndrome?

Key symptoms include joint pain and swelling, particularly in the knees, along with systemic symptoms such as fatigue, splenomegaly, and leukopenia.