Graduation Date

Fall 12-18-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Programs

Medical Sciences Interdepartmental Area

First Advisor

Kaleb Michaud, PhD

Second Advisor

Andrew Dudley, PhD

Third Advisor

Yvonne Golightly, PT, PhD

Fourth Advisor

Ryan Arnold, MD

Abstract

Articular cartilage structure and chondrocyte health are sensitive and reliant on dynamic joint loading during activities. The risk of osteoarthritis (OA) is high after anterior cruciate ligament (ACL) injury, but mechanisms underlying its development are poorly understood. The overall goals of this work were 1) to determine the association between measures of individual and cumulative knee joint loading with T2 relaxation times in the knee cartilage of young individuals without injury and 2) to determine if these same knee joint loading factors are associated with cartilage T2 relaxation time one month after ACL injury. The central hypotheses was that lower measures of knee joint loading would be associated with higher (worse) T2 relaxation time throughout the articular cartilage of knees with and without ACL injury. Individuals without a history of knee injury and with an acute ACL injury in the past month served as participants for this study. Participants completed magnetic resonance imaging with T2 mapping, biomechanical gait analysis, and one week of accelerometry during daily living to measure T2 relaxation time, knee joint angles and moments, and daily physical activity levels, respectively. Individual loading factors and cumulative knee joint loading were correlated with higher T2 relaxation times in the articular cartilage of uninjured knees. Altered knee joint adduction moment impulse, less knee flexion excursion, and higher daily physical activity were associated with prolonged T2 relaxation time one month after ACL injury. Gait biomechanics and daily PA may be modifiable targets to alter OA development acutely after ACL injury.

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