MRI Does Not Reliably Detect Kaplan Fiber Injury In Skeletally Immature Patients with an Acute ACL Tear

Area of Science:

• Orthopedic Surgery
• Radiology
• Pediatric Sports Medicine

Background:

• Kaplan fiber (KF) injury prevalence in skeletally immature patients with acute anterior cruciate ligament (ACL) tears on MRI is not well-established.
• Previous diagnostic criteria for KF injury have not been compared for reliability in this specific patient population.

Purpose of the Study:

• To determine the prevalence of KF injury in skeletally immature patients with acute ACL tears using MRI within 90 days of injury.
• To compare the reliability of two diagnostic criteria (Van Dyck and Batty) for detecting KF injuries on MRI in this cohort.

Main Methods:

• A cohort of 45 skeletally immature patients with acute ACL tears underwent MRI within 90 days of injury.
• Two musculoskeletal radiologists independently assessed KF injury using the Van Dyck and Batty criteria, with discrepancies adjudicated by a third radiologist.
• Interrater agreement was calculated using Cohen κ for both diagnostic schemes.

Main Results:

• KF injuries were identified in 37.7% of knees using the Van Dyck scheme and 11.1% using the Batty criteria.
• Interrater agreement was poor for both methods (κ = 0.40 for Van Dyck, κ = 0.45 for Batty).
• A significant number of scans required third-reviewer adjudication for both criteria.

Conclusions:

• The Batty criteria identified a lower prevalence of KF injury compared to adult populations, while the Van Dyck scheme showed similar prevalence.
• Both the Van Dyck and Batty diagnostic criteria exhibit poor interrater reliability for diagnosing Kaplan fiber injuries in skeletally immature patients with ACL tears on MRI.