A comparison of three methods for measuring patella malalignment in children

Area of Science:

• Pediatric Orthopedics
• Biomechanical Analysis
• Radiographic Measurement Techniques

Background:

• Accurate measurement of patellar alignment is crucial for diagnosing and managing pediatric knee conditions.
• Traditional methods like Insall-Salvati (IS) and Blackburne-Peel (BP) face challenges in pediatric populations due to incomplete ossification.
• The Koshino-Sugimoto (KS) method offers an alternative approach using specific physeal and patellar landmarks.

Purpose of the Study:

• To evaluate the accuracy and reliability of the Insall-Salvati (IS), Blackburne-Peel (BP), and Koshino-Sugimoto (KS) methods for assessing patellar malalignment in children.
• To identify the most suitable radiographic technique for pediatric patellar malalignment measurement.
• To determine the optimal knee flexion angle for the KS method in pediatric assessment.

Main Methods:

• Comparative analysis of three radiographic measurement techniques: IS, BP, and KS.
• Assessment of landmark identification in pediatric knees with incomplete ossification.
• Evaluation of the KS method's accuracy in both extended and flexed knee positions.

Main Results:

• The IS and BP methods demonstrated inaccuracies in children due to the absence of traditional ossified landmarks.
• The KS method applied to the extended knee showed inaccuracies attributed to patellar ligament laxity.
• The KS method applied to the flexed knee proved to be the most accurate and reliable technique for measuring patellar malalignment in the pediatric population.

Conclusions:

• Traditional methods (IS, BP) are unreliable for pediatric patellar malalignment assessment.
• The Koshino-Sugimoto (KS) method, particularly when applied to a flexed knee, is the preferred technique for accurate pediatric patellar malalignment measurement.
• Flexed knee imaging is essential for optimizing the accuracy of the KS method in children.