A novel sonographic method of measuring patellar tendon length

Area of Science:

• Orthopedics
• Medical Imaging
• Anatomy

Background:

• Accurate and repeatable measurements of soft tissue structures are crucial for clinical and research applications.
• Limited research exists on the interrater reliability of ultrasound measurements for tendons.

Purpose of the Study:

• To determine the accuracy and reliability of a novel sonographic method for measuring patellar tendon length.
• To compare ultrasound measurements with direct dissection as the gold standard.

Main Methods:

• Two investigators performed sonographic evaluations on four cadaveric knees.
• Custom straps marked leg position and created acoustic shadows on ultrasound images.
• Anatomic landmarks included the distal patellar pole and anterior proximal tibial ridge. Measurements were validated against digital caliper measurements of dissected tendons.

Main Results:

• The intraclass correlation coefficient (ICC) between raters was 0.96, indicating excellent reliability.
• Bland-Altman analysis showed a bias of 0.17 mm and a standard deviation of 0.71 mm.
• The 95% limits of agreement were -1.55 mm to 1.22 mm, demonstrating high accuracy.

Conclusions:

• Ultrasound measurement of patellar tendon length using adjustable surface markers and calipers is a highly accurate method.
• The technique demonstrates good interrater reliability, making it suitable for clinical and research settings.