Effects of Prolonged Load Carriage of Knee Adduction Biomechanics

Introduction: Incidence of knee osteoarthritis (OA) in service members is twice that of the general population. Yet, it is currently unknown how body borne load and duration of walking with body borne load impact knee adduction, biomechanics linked to progression and severity of OA. Purpose: This study sought to examine magnitude and variability of knee adduction joint angle and moment throughout a prolonged walking task with body borne load. Methods: Eighteen participants had knee biomechanics quantified every five minutes while they walked at 1.3 m/s during a 60-minute over-ground walking task with three body-borne loads (unloaded, 15 kg and 30 kg). Statistical Analysis: Thirteen participants with complete data sets were submitted to statistical analysis. Peak of stance (0-100%) knee adduction joint angle and moment, initial contact and range of adduction motion, and coefficient of variation of peak knee adduction angle and moment, and range of adduction motion were submitted to a repeated measures ANOVA to test the main effect and interaction between time (0, 15, 30, 45 and 60 min) and load (0 ,15 and 30 kg). Results: Body borne load significantly increased peak knee adduction moment (p0.05); whereas duration of walking task significantly increased peak stance (p0.05). Conclusion: Prolonged walking with body borne load increased knee adduction biomechanics related to knee OA pathogenesis. The larger knee adduction moment exhibited with the addition of load and the larger knee adduction angle exhibited towards the end of the prolonged walking task may increase loading of the medial knee joint compartment and increase risk of knee OA