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v1.0.0
ICD-10 Guide
ICD-10 CodesM21.261

M21.261

Billable

Flexion deformity, right knee

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

Code Description

ICD-10 M21.261 is a billable code used to indicate a diagnosis of flexion deformity, right knee.

Key Diagnostic Point:

Flexion deformity of the right knee is characterized by an abnormal bending of the knee joint, resulting in a reduced ability to fully extend the leg. This condition can arise from various acquired factors, including trauma, arthritis, or neurological disorders. Patients may present with limited range of motion, pain, and difficulty in ambulation. The deformity can lead to compensatory mechanisms in gait, potentially causing secondary issues in the hip and ankle joints. Treatment options often include physical therapy, bracing, or surgical interventions such as osteotomy or arthroplasty, depending on the severity and underlying cause of the deformity. Accurate diagnosis and documentation are crucial for effective management and coding, as the degree of flexion and associated symptoms can significantly influence treatment decisions.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in clinical presentation and severity of the deformity
  • Need for detailed documentation of range of motion and functional limitations
  • Potential for co-existing conditions affecting the knee
  • Differentiation from other knee deformities such as varus or valgus deformities

Audit Risk Factors

  • Inadequate documentation of the degree of flexion
  • Failure to document the impact on daily activities
  • Lack of evidence for conservative treatment attempts before surgical intervention
  • Misclassification of the deformity type

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Detailed physical examination notes, imaging results, and treatment history.

Common Clinical Scenarios

Patients with post-traumatic knee flexion deformities, degenerative joint disease leading to flexion contractures.

Billing Considerations

Ensure to document the specific degree of flexion and any associated functional limitations.

Physical Medicine and Rehabilitation

Documentation Requirements

Functional assessments, therapy progress notes, and patient-reported outcomes.

Common Clinical Scenarios

Patients undergoing rehabilitation for knee flexion deformities post-surgery or injury.

Billing Considerations

Document the impact of the deformity on rehabilitation goals and patient mobility.

Coding Guidelines

Inclusion Criteria

Use M21.261 When
  • Follow the official ICD
  • CM guidelines for coding and reporting, ensuring to capture the specific nature of the flexion deformity and any associated conditions
  • Include documentation of the patient's history, physical examination findings, and treatment plans

Exclusion Criteria

Do NOT use M21.261 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

27447CPT Code

Total knee arthroplasty

Clinical Scenario

Used for patients with severe flexion deformity requiring surgical intervention.

Documentation Requirements

Pre-operative assessment, imaging studies, and surgical notes.

Specialty Considerations

Orthopedic surgeons must document the rationale for surgery based on functional limitations.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of knee deformities, improving the accuracy of diagnoses and treatment plans. M21.261 provides a clear distinction for acquired flexion deformities, facilitating better patient management and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of knee deformities, improving the accuracy of diagnoses and treatment plans. M21.261 provides a clear distinction for acquired flexion deformities, facilitating better patient management 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 flexion deformity in the knee?

Flexion deformity can result from various factors, including trauma, degenerative joint disease, or neurological conditions that affect muscle control and joint stability.