Musculoskeletal condition M22.42 — ICD-10 M22.42

ICD-10: M22.42 | Category: Other Joint Disorders | Billable: Yes

Patellar subluxation, classified under ICD-10 code M22.42, refers to a partial dislocation of the patella (kneecap) from its normal position within the femoral groove. This condition can lead to significant discomfort and functional limitations, particularly in athletes and active individuals. While it may occur acutely due to trauma, it often develops gradually as a result of chronic instability or underlying anatomical abnormalities.

The patella is a sesamoid bone located within the quadriceps tendon, serving to protect the knee joint and enhance the leverage of the quadriceps muscle during knee extension. The patella articulates with the femur in a groove known as the trochlear groove.

Biomechanics

During movements such as walking, running, or jumping, the patella glides along this groove. Proper alignment and tracking are crucial for optimal knee function. Factors such as muscle imbalances, ligament laxity, or bony abnormalities can disrupt this alignment, leading to subluxation.

Patient presents with a 35-year-old female who reports recurrent episodes of her knee giving way while running. She mentions a previous history of patellar dislocation. Upon examination, she exhibits tenderness over the lateral aspect of the knee and a positive apprehension test. Code as M22.42 because the documentation supports patellar instability due to the recurrent dislocation and current symptoms consistent with the ICD-10-CM guideline for this condition.

To support medical necessity and minimize claim denials for ICD-10 code M22.42, the following documentation elements should be included:

• Comprehensive Patient History: Detailed documentation of the patient’s previous knee issues, including any prior dislocations, treatments, and responses to therapy.

• Physical Examination Findings: Clear notes on the clinical examination, including specific tests performed (e.g., apprehension test), range of motion, and any observable symptoms.

• Diagnostic Imaging: If applicable, include reports from any imaging studies (e.g., MRI, X-rays) that confirm the diagnosis of patellar instability.

• Treatment Plan: Document the rationale for the chosen treatment plan, including any referrals to physical therapy or recommendations for orthopedic consultation.

• Follow-Up Notes: Include notes from follow-up visits to track the patient's progress and any changes in symptoms or treatment efficacy.

Subjective: A 28-year-old male athlete presents with complaints of right knee instability during activities such as jumping and squatting. He reports that his knee felt unstable after a recent basketball game, and he has experienced similar episodes in the past year. Objective: Upon examination, the patient demonstrates swelling in the right knee and mild tenderness along the medial patellar facet. Range of motion is intact, but there is a noticeable apprehension when the patella is laterally displaced during the examination. No ligamentous instability is noted. Assessment: M22.42 - Patellar instability. The patient exhibits signs consistent with recurrent patellar dislocation, leading to instability. Plan: Recommend a physical therapy regimen focused on strengthening the quadriceps and hamstrings. Discuss the importance of using knee braces during high-impact activities. Schedule a follow-up appointment in 4 weeks to assess progress and adjust the treatment plan as necessary.

When diagnosing patellar subluxation (M22.42), it is important to consider other conditions that may present similarly:

1. Patellar Dislocation (M22.41): Complete dislocation requiring different management strategies.
2. Patellofemoral Pain Syndrome (M22.9): Characterized by anterior knee pain without instability.
3. Chondromalacia Patella (M94.20): Degeneration of cartilage under the kneecap leading to pain but not necessarily instability.

Accurate documentation is essential for billing purposes under ICD-10 code M22.42:

1. Document patient history including onset, mechanism of injury, and previous episodes.
2. Include detailed physical examination findings supporting diagnosis.
3. Outline treatment plans including specific interventions used during rehabilitation phases.
4. Record patient progress regularly, noting improvements or setbacks.

Proper coding ensures appropriate reimbursement while maintaining compliance with regulatory standards.