Knee adduction moment during gait, hip abductor torque, biomarkers: study of knee osteoarthritis progression

Abstract

Introduction: The knee osteoarthritis (OA) of medial compartment is more common and excessive loading has been considered the most common cause. The knee adduction moment (KAM) is a reliable and valid indicator of medial knee load during gait. Whereas the MAJ is related to the hip abductor torque and kinematics of the proximal segments (inclination of the trunk) and distal (toe-out angle) to the knee, the concomitant assessment of these variables is important for understanding the influence of these variables on the MAJ during gait in knee OA patients. The MAJ is related with progression of articular cartilage degradation, which is assessed by measurement of biomarkers. The investigation of the relationship between MAJ and biomarkers will contribute to a better understanding of the influence of mechanical forces on the metabolic behavior of cartilage of individuals with differences in knee OA severity levels. Objective: This study aims to analyze the knee adduction moment, lateral trunk lean and toe-out angle during gait, as well as hip abductor torque and the levels of urinary C-terminal telopeptide of collagen (uCTX-II) and serum Collagen Oligomeric Matrix Protein (sCOMP) in subjects with differences in knee OA severity levels. Methods: Will be selected 45 individuals, 15 of the group of knee OA grade II , 15 grade III knee OA and 15 controls . The diagnosis of knee OA will be based on the American College of Rheumatology criteria and the classification with Kellgren and Lawrence (1957). Individuals will be included with OA and pain predominantly in the medial compartment, aged between 40 and 80 years. Volunteers will be evaluated kinetic and kinematic three-dimensional gait performed by the system Qualisys Motion Capture (Qualisys Medical AB, Sweden) synchronized to two force platforms (Bertec, OH, USA). The hip abductor torque will be assessment with an isokinetic dynamometer (Biodex Medical Systems, NY, USA) by 5 maximal repetitions at 30°/s. The uCTX-II level will be assayed with a competitive enzyme-linked immunosorbent assay (ELISA). uCTX-II values will be adjusted by their total creatinine concentration in the urine (mmol/L). The WOMAC questionnaire will be used to assess pain, stiffness and physical function of the participants . Intergroup analysis of kinetic variables, kinematic and level of uCTX-II and sCOMP will be conducted through one-way ANOVA. Correlation analysis between the dependent variables (MAJ) and independent (kinematic, torque, uCTX-II level, knee alignment, pain, stiffness and physical function) will be performed using the Pearson or Spearman test according to data distribution.